Nonsteroidal anti-inflammatory drugs (NSAIDs) cause an increased risk of serious cardiovascular thrombotic events, including myocardial infarction (MI) and stroke, which can be fatal. This risk may occur early in treatment and may increase with duration of use.
Mefenamic acid is contraindicated during the perioperative setting of coronary artery bypass graft (CABG) surgery.
NSAIDs cause an increased risk of serious gastrointestinal (GI) adverse events, including bleeding, ulceration, and perforation of the stomach or intestines, which can be fatal. These events can occur at any time during use and without warning symptoms. Elderly patients and patients with a prior history of peptic ulcer disease and/or GI bleeding are at greater risk for serious GI events.
Note: Safety: Use the lowest effective dose for the shortest duration of time. Avoid or use with caution in patients at risk for or with existing cardiovascular disease, GI disease, kidney impairment, chronic liver disease, or a bleeding diathesis due to greater risk for adverse events. Consider administering in combination with a proton pump inhibitor in patients at risk for GI bleeding (eg, taking dual antiplatelet therapy or an anticoagulant, ≥60 years of age, high doses) (Ref).
Abnormal uterine bleeding, nonacute (alternative agent) (off-label use): Note: Not indicated for management of acute abnormal bleeding (ie, excessively heavy or prolonged bleeding that requires urgent evaluation). Alternative agent for patients who cannot or choose not to use hormonal therapies (Ref).
Oral: 500 mg 3 times daily or 500 mg once followed by 250 mg 4 times daily. Begin at the first sign of menses and continue for 2 to 3 days or until cessation of bleeding; maximum dose: 1.5 g/day (Ref).
Pain, mild to moderate: Oral: Initial: 500 mg, then 250 mg every 6 hours as needed; usually not to exceed 1 week.
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
Avoid use in patients with preexisting renal disease and in patients with advanced renal disease.
KDIGO 2012 guidelines provide the following recommendations for NSAIDs:
eGFR 30 to <60 mL/minute/1.73 m2: Temporarily discontinue in patients with intercurrent disease that increases risk of acute kidney injury.
eGFR <30 mL/minute/1.73 m2: Avoid use.
Hepatic impairment prior to treatment initiation: There are no dosage adjustments provided in the manufacturer's labeling (has not been studied); however, adjustment may be necessary due to extensive hepatic metabolism.
Hepatotoxicity during treatment: Discontinue if clinical signs and symptoms of liver disease develop, or if systemic manifestations occur.
Note: Unless alternative agents are ineffective and a gastroprotective agent can be administered, avoid short-term scheduled use in combination with corticosteroids, anticoagulants, or antiplatelet agents or chronic use with or without medications that increase risk for bleeding (Ref).
Refer to adult dosing; initiate dose at lower end of the dosing range.
Pain, mild to moderate: Adolescents ≥14 years: Refer to adult dosing.
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
Avoid use in patients with preexisting renal disease and in patients with advanced renal disease.
KDIGO 2012 guidelines provide the following recommendations for NSAIDs:
eGFR 30 to <60 mL/minute/1.73 m2: Temporarily discontinue in patients with intercurrent disease that increases risk of acute kidney injury.
eGFR <30 mL/minute/1.73 m2: Avoid use.
There are no dosage adjustments provided in the manufacturer’s labeling (has not been studied); however, adjustment may be necessary due to extensive hepatic metabolism.
The following adverse drug reactions are derived from product labeling unless otherwise specified. Reactions listed are based on reports for other agents in this same pharmacologic class (NSAIDs) and may not be specifically reported for mefenamic acid.
Postmarketing:
Cardiovascular: Acute myocardial infarction, cardiac arrhythmia, edema, heart failure, hypertension, hypotension, palpitations, syncope, tachycardia, thrombosis, vasculitis
Dermatologic: Alopecia, bullous pemphigoid (Shepherd 1986), diaphoresis, ecchymoses, erythema multiforme, exfoliative dermatitis, fixed drug eruption (Ouni 2021), pruritus, skin photosensitivity, skin rash, Stevens-Johnson syndrome, toxic epidermal necrolysis, urticaria
Endocrine & metabolic: Hyperglycemia, hypoalbuminemia (Kaosombetwattna 2017), weight changes (including weight loss) (Kaosombetwattna 2017)
Gastrointestinal: Abdominal pain, change in appetite, colitis (Kaosombetwattna 2017), constipation, diarrhea (Isaacs 1987; Kaosombetwattna 2017), dyspepsia, eructation, esophagitis, flatulence, gastritis, gastrointestinal disease (enteropathy [including atrophic mucosa, intestinal inflammation, villous atrophy, villous blunting]) (Isaacs 1987; Kaosombetwattna 2017), gastrointestinal hemorrhage, gastrointestinal inflammation, gastrointestinal perforation (including esophageal perforation, intestinal perforation), gastrointestinal ulcer (including duodenal ulcer, esophageal ulcer, gastric ulcer, peptic ulcer) (Kaosombetwattna 2017; Katsinelos 1999), glossitis, heartburn, hematemesis, melena, nausea, pancreatitis (VanWalraven 1982), rectal hemorrhage, steatorrhea (Isaacs 1987), stomatitis, vomiting, xerostomia
Genitourinary: Cystitis, dysuria, hematuria, oliguria, polyuria, proteinuria
Hematologic & oncologic: Agranulocytosis, anemia (Kaosombetwattna 2017), aplastic anemia, eosinophilia, hemolytic anemia, leukopenia (Handa 1990), lymphadenopathy, neutropenia (Handa 1990), pancytopenia, prolonged bleeding time, purpuric disease, thrombocytopenia
Hepatic: Hepatic failure, hepatitis, hepatotoxicity (idiosyncratic) (Chalasani 2021), increased liver enzymes (including increased serum alanine aminotransferase, increased serum aspartate aminotransferase), jaundice
Hypersensitivity: Anaphylaxis, angioedema, drug reaction with eosinophilia and systemic symptoms, nonimmune anaphylaxis
Infection: Infection, sepsis
Nervous system: Abnormal dreams, anxiety, asthenia, cerebrovascular accident, coma, confusion, depression, dizziness, drowsiness, hallucination, headache, insomnia, malaise, meningitis, nervousness, paresthesia, seizure, tremor, vertigo
Neuromuscular & skeletal: Dyskinesia (Redmond 1981)
Ophthalmic: Acute angle-closure glaucoma (secondary) (Vishwakarma 2009), blurred vision, choroidal detachment (Vishwakarma 2009), conjunctivitis, myopia (Vishwakarma 2009)
Otic: Auditory impairment, tinnitus
Renal: Glomerulonephritis (Segasothy 1987), increased serum creatinine (Drury 1981), interstitial nephritis (Segasothy 1987), kidney failure (Segasothy 1987), renal papillary necrosis (Segasothy 1987)
Respiratory: Asthma, dyspnea, pneumonia, respiratory depression
Miscellaneous: Fever
Hypersensitivity (eg, anaphylaxic reactions, serious skin reactions) to mefenamic acid, or any component of the formulation; use in the setting of coronary artery bypass graft (CABG) surgery; history of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs.
Canadian labeling: Additional contraindications (not in US labeling): Pregnancy (third trimester); breast-feeding; severe uncontrolled heart failure; active gastric, duodenal, or peptic ulcer; active gastrointestinal bleeding; cerebrovascular bleeding or other bleeding disorders; inflammatory bowel disease; severe hepatic impairment or active hepatic disease; severe renal impairment (CrCl <30 mL/minute) or deteriorating renal disease; known hyperkalemia; adolescents <18 years of age
Concerns related to adverse effects:
• Anaphylactoid reactions: Even in patients without prior exposure anaphylactoid reactions may occur; patients with "aspirin triad" (bronchial asthma, aspirin intolerance, rhinitis) may be at increased risk. Contraindicated in patients who experience bronchospasm, asthma, rhinitis, or urticaria with nonsteroidal anti-inflammatory drug (NSAID) or aspirin therapy.
• Cardiovascular events: Relative risk appears to be similar in those with and without known cardiovascular disease or risk factors for cardiovascular disease; however, absolute incidence of serious cardiovascular thrombotic events (which may occur early during treatment) was higher in patients with known cardiovascular disease or risk factors and in those receiving higher doses. New onset hypertension or exacerbation of hypertension may occur (NSAIDs may also impair response to ACE inhibitors, thiazide diuretics, or loop diuretics); may contribute to cardiovascular events; monitor blood pressure; use with caution in patients with hypertension. May cause sodium and fluid retention; use with caution in patients with edema. Avoid use in heart failure (FDA 2015). Avoid use in patients with recent MI unless benefits outweigh risk of cardiovascular thrombotic events. Use the lowest effective dose for the shortest duration of time, consistent with individual patient goals, to reduce risk of cardiovascular events; consider alternate therapies for patients at high risk.
• CNS effects: May cause drowsiness, dizziness, blurred vision, and other neurologic effects which may impair physical or mental abilities; patients must be cautioned about performing tasks which require mental alertness (eg, operating machinery or driving).
• Drug reaction with eosinophilia and systemic symptoms: Potentially serious, sometimes fatal, drug reaction with eosinophilia and systemic symptoms (DRESS), also known as multiorgan hypersensitivity reactions, has been reported with NSAIDs. Monitor for signs and symptoms (eg, fever, rash, lymphadenopathy, eosinophilia) in association with other organ system involvement (eg, hepatitis, nephritis, hematological abnormalities, myocarditis, myositis). Early symptoms of hypersensitivity reaction (eg, lymphadenopathy, fever) may occur without rash; discontinue therapy and further evaluate if DRESS is suspected.
• GI events: Avoid use in patients with active GI bleeding. In patients with a history of acute lower GI bleeding, avoid use of non-aspirin NSAIDs, especially if due to angioectasia or diverticulosis (Strate 2016). Use caution with a history of GI ulcers, concurrent therapy known to increase the risk of GI bleeding (eg, aspirin, anticoagulants and/or corticosteroids, selective serotonin reuptake inhibitors), advanced hepatic disease, coagulopathy, smoking, use of alcohol, or in the elderly or debilitated patients. Use the lowest effective dose for the shortest duration of time, consistent with individual patient goals, to reduce risk of GI adverse events; consider alternate therapies for patients at high risk. When used concomitantly with aspirin, a substantial increase in the risk of GI complications (eg, ulcer) occurs; concomitant gastroprotective therapy (eg, proton pump inhibitors) is recommended (ACCF/ACG/AHA [Bhatt 2008]).
• Hematologic effects: Platelet adhesion and aggregation may be decreased; may prolong bleeding time; monitor patients with coagulation disorders or who are receiving anticoagulants closely. Anemia may occur; monitor patients on long-term NSAID therapy for anemia. Rarely, NSAID use has been associated with potentially severe blood dyscrasias (eg, agranulocytosis, thrombocytopenia, aplastic anemia).
• Hepatic effects: Transaminase elevations have been reported with use; closely monitor patients with any abnormal LFT. Rare (sometimes fatal) severe hepatic reactions (eg, fulminant hepatitis, hepatic necrosis, hepatic failure) have occurred with NSAID use; discontinue immediately if clinical signs or symptoms of hepatic disease develop or if systemic manifestations occur.
• Hyperkalemia: NSAID use may increase the risk of hyperkalemia, particularly in the elderly, diabetics, renal disease, and with concomitant use of other agents capable of inducing hyperkalemia (eg, ACE-inhibitors). Monitor potassium closely.
• Renal effects: NSAID use may compromise existing renal function; dose-dependent decreases in prostaglandin synthesis may result from NSAID use, reducing renal blood flow which may cause renal decompensation (usually reversible). Patients with impaired renal function, dehydration, hypovolemia, heart failure, hepatic impairment, those taking diuretics, ACE inhibitors, and the elderly are at greater risk of renal toxicity. Rehydrate patient before starting therapy; monitor renal function closely. Long-term NSAID use may result in renal papillary necrosis and other renal injury.
• Skin reactions: NSAIDs may cause serious skin adverse events (sometimes fatal), including exfoliative dermatitis, fixed drug eruption (including generalized bullous fixed drug eruption), Stevens-Johnson syndrome, and toxic epidermal necrolysis; may occur without warning and in patients without prior known sulfa allergy; discontinue use at first sign of rash (or any other hypersensitivity).
Disease-related concerns:
• Asthma: Contraindicated in patients with aspirin-sensitive asthma; severe and potentially fatal bronchospasm may occur. Use caution in patients with other forms of asthma.
• Hepatic impairment: Use with caution in patients with hepatic impairment; dosage adjustments may be necessary due to extensive hepatic metabolism. Patients with advanced hepatic disease are at an increased risk of GI bleeding with NSAIDs.
• Renal impairment: Avoid use in patients with preexisting renal disease and in patients with advanced renal disease; monitor renal function closely if therapy must be initiated.
Other warnings/precautions:
• Surgical/dental procedures: Withhold for at least 4 to 6 half-lives prior to surgical or dental procedures.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Capsule, Oral:
Generic: 250 mg
Yes
Capsules (Mefenamic Acid Oral)
250 mg (per each): $17.33 - $17.41
Disclaimer: A representative AWP (Average Wholesale Price) price or price range is provided as reference price only. A range is provided when more than one manufacturer's AWP price is available and uses the low and high price reported by the manufacturers to determine the range. The pricing data should be used for benchmarking purposes only, and as such should not be used alone to set or adjudicate any prices for reimbursement or purchasing functions or considered to be an exact price for a single product and/or manufacturer. Medi-Span expressly disclaims all warranties of any kind or nature, whether express or implied, and assumes no liability with respect to accuracy of price or price range data published in its solutions. In no event shall Medi-Span be liable for special, indirect, incidental, or consequential damages arising from use of price or price range data. Pricing data is updated monthly.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product
Capsule, Oral:
Ponstan: 250 mg [DSC] [contains fd&c blue #1 (brilliant blue), fd&c yellow #6 (sunset yellow), quinoline yellow (d&c yellow #10)]
Generic: 250 mg
Oral: May administer with food to reduce GI upset (Ref).
Oral: May take with food if it causes an upset stomach.
An FDA-approved patient medication guide, which is available with the product information and at https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/015034s046lbl.pdf, must be dispensed with this medication.
Dysmenorrhea, primary: Treatment of primary dysmenorrhea.
Pain, mild to moderate: Relief of mild to moderate pain in patients ≥14 years, when therapy will not exceed 1 week.
Abnormal uterine bleeding, nonacute
Ponstel may be confused with Pronestyl
Beers Criteria: Mefenamic acid is identified in the Beers Criteria as a potentially inappropriate medication to be avoided for chronic use in patients 65 years and older (unless alternative agents ineffective and patient can receive concomitant gastroprotective agent) due to increased risk of GI bleeding and peptic ulcer disease in older adults in high risk category (eg, older than 75 years or receiving concomitant oral/parenteral corticosteroids, anticoagulants, or antiplatelet agents). In addition, avoid for short-term scheduled use in combination with oral/parenteral corticosteroids, anticoagulants, or antiplatelet agents unless alternatives are ineffective and patient can receive concomitant gastroprotective agent (Beers Criteria [AGS 2023]).
Substrate of CYP2C9 (Minor); Note: Assignment of Major/Minor substrate status based on clinically relevant drug interaction potential; Inhibits UGT1A9;
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program by clicking on the “Launch drug interactions program” link above.
5-Aminosalicylic Acid Derivatives: Nonsteroidal Anti-Inflammatory Agents may increase nephrotoxic effects of 5-Aminosalicylic Acid Derivatives. Risk C: Monitor
Abciximab: May increase antiplatelet effects of Agents with Antiplatelet Effects. Risk C: Monitor
Abrocitinib: Agents with Antiplatelet Effects may increase antiplatelet effects of Abrocitinib. Risk X: Avoid
Acalabrutinib: May increase antiplatelet effects of Agents with Antiplatelet Effects. Risk C: Monitor
Acemetacin: May increase adverse/toxic effects of Nonsteroidal Anti-Inflammatory Agents. Risk X: Avoid
Alcohol (Ethyl): May increase adverse/toxic effects of Nonsteroidal Anti-Inflammatory Agents. Specifically, the risk of GI bleeding may be increased with this combination. Risk C: Monitor
Aliskiren: Nonsteroidal Anti-Inflammatory Agents may increase nephrotoxic effects of Aliskiren. Nonsteroidal Anti-Inflammatory Agents may decrease antihypertensive effects of Aliskiren. Risk C: Monitor
Aminoglycosides: Nonsteroidal Anti-Inflammatory Agents may decrease excretion of Aminoglycosides. Data only in premature infants. Risk C: Monitor
Aminolevulinic Acid (Systemic): Photosensitizing Agents may increase photosensitizing effects of Aminolevulinic Acid (Systemic). Risk X: Avoid
Aminolevulinic Acid (Topical): Photosensitizing Agents may increase photosensitizing effects of Aminolevulinic Acid (Topical). Risk C: Monitor
Anagrelide: May increase antiplatelet effects of Agents with Antiplatelet Effects. Risk C: Monitor
Angiotensin II Receptor Blockers: Nonsteroidal Anti-Inflammatory Agents may decrease therapeutic effects of Angiotensin II Receptor Blockers. The combination of these two agents may also significantly decrease glomerular filtration and renal function. Angiotensin II Receptor Blockers may increase adverse/toxic effects of Nonsteroidal Anti-Inflammatory Agents. Specifically, the combination may result in a significant decrease in renal function. Risk C: Monitor
Angiotensin-Converting Enzyme Inhibitors: Nonsteroidal Anti-Inflammatory Agents may decrease antihypertensive effects of Angiotensin-Converting Enzyme Inhibitors. Angiotensin-Converting Enzyme Inhibitors may increase adverse/toxic effects of Nonsteroidal Anti-Inflammatory Agents. Specifically, the combination may result in a significant decrease in renal function. Risk C: Monitor
Anticoagulants (Miscellaneous Agents): Nonsteroidal Anti-Inflammatory Agents (Nonselective) may increase anticoagulant effects of Anticoagulants (Miscellaneous Agents). Risk C: Monitor
Antiplatelet Agents (P2Y12 Inhibitors): Agents with Antiplatelet Effects may increase antiplatelet effects of Antiplatelet Agents (P2Y12 Inhibitors). Risk C: Monitor
Aspirin: Nonsteroidal Anti-Inflammatory Agents (Nonselective) may decrease therapeutic effects of Aspirin. Aspirin may increase adverse/toxic effects of Nonsteroidal Anti-Inflammatory Agents (Nonselective). Specifically, the risk for bleeding may be increased. Aspirin may decrease serum concentration of Nonsteroidal Anti-Inflammatory Agents (Nonselective). Management: In general, avoid regular, frequent use of NSAIDs with aspirin whenever possible. If combined, monitor for increased bleeding and a reduced cardioprotective effect of aspirin. Risk D: Consider Therapy Modification
Bemiparin: Nonsteroidal Anti-Inflammatory Agents (Nonselective) may increase anticoagulant effects of Bemiparin. Management: Avoid this combination if possible, due to an increased risk of bleeding. If coadministration cannot be avoided, monitor patients closely for clinical and laboratory evidence of bleeding. Risk D: Consider Therapy Modification
Beta-Blockers: Nonsteroidal Anti-Inflammatory Agents may decrease antihypertensive effects of Beta-Blockers. Risk C: Monitor
Bile Acid Sequestrants: May decrease absorption of Nonsteroidal Anti-Inflammatory Agents. Risk C: Monitor
Bisphosphonate Derivatives: Nonsteroidal Anti-Inflammatory Agents may increase adverse/toxic effects of Bisphosphonate Derivatives. Both an increased risk of gastrointestinal ulceration and an increased risk of nephrotoxicity are of concern. Risk C: Monitor
Caplacizumab: Agents with Antiplatelet Effects may increase adverse/toxic effects of Caplacizumab. Specifically, the risk of bleeding may be increased. Risk C: Monitor
Cardiac Glycosides: Nonsteroidal Anti-Inflammatory Agents may increase serum concentration of Cardiac Glycosides. Risk C: Monitor
Collagenase (Systemic): Agents with Antiplatelet Effects may increase adverse/toxic effects of Collagenase (Systemic). Specifically, the risk of injection site bruising and or bleeding may be increased. Risk C: Monitor
Corticosteroids (Systemic): May increase adverse/toxic effects of Nonsteroidal Anti-Inflammatory Agents (Nonselective). Risk C: Monitor
CycloSPORINE (Systemic): Nonsteroidal Anti-Inflammatory Agents may increase nephrotoxic effects of CycloSPORINE (Systemic). Nonsteroidal Anti-Inflammatory Agents may increase serum concentration of CycloSPORINE (Systemic). CycloSPORINE (Systemic) may increase serum concentration of Nonsteroidal Anti-Inflammatory Agents. Management: Consider alternatives to nonsteroidal anti-inflammatory agents (NSAIDs). Monitor for evidence of nephrotoxicity, as well as increased serum cyclosporine concentrations and systemic effects (eg, hypertension) during concomitant therapy with NSAIDs. Risk D: Consider Therapy Modification
Dasatinib: May increase antiplatelet effects of Agents with Antiplatelet Effects. Risk C: Monitor
Deferasirox: Nonsteroidal Anti-Inflammatory Agents may increase adverse/toxic effects of Deferasirox. Specifically, the risk for GI ulceration/irritation or GI bleeding may be increased. Risk C: Monitor
Deoxycholic Acid: May increase antiplatelet effects of Agents with Antiplatelet Effects. Risk C: Monitor
Desirudin: Nonsteroidal Anti-Inflammatory Agents (Nonselective) may increase anticoagulant effects of Desirudin. Risk C: Monitor
Desmopressin: Nonsteroidal Anti-Inflammatory Agents may increase hyponatremic effects of Desmopressin. Risk C: Monitor
Direct Oral Anticoagulants (DOACs): Nonsteroidal Anti-Inflammatory Agents (Nonselective) may increase anticoagulant effects of Direct Oral Anticoagulants (DOACs). Risk C: Monitor
Drospirenone-Containing Products: May increase hyperkalemic effects of Nonsteroidal Anti-Inflammatory Agents. Risk C: Monitor
Enoxaparin: Nonsteroidal Anti-Inflammatory Agents (Nonselective) may increase anticoagulant effects of Enoxaparin. Management: Discontinue nonselective NSAIDs prior to initiation of enoxaparin whenever possible. If coadministration cannot be avoided, monitor patients closely for clinical and laboratory evidence of bleeding. Risk D: Consider Therapy Modification
Eplerenone: Nonsteroidal Anti-Inflammatory Agents may decrease antihypertensive effects of Eplerenone. Nonsteroidal Anti-Inflammatory Agents may increase hyperkalemic effects of Eplerenone. Risk C: Monitor
Fondaparinux: Nonsteroidal Anti-Inflammatory Agents (Nonselective) may increase anticoagulant effects of Fondaparinux. Management: Discontinue nonselective nonsteroidal anti-inflammatory agents prior to the initiation of fondaparinux, if possible. If coadministration is required, monitor patients closely for signs and symptoms of bleeding. Risk D: Consider Therapy Modification
Glycoprotein IIb/IIIa Inhibitors: Agents with Antiplatelet Effects may increase antiplatelet effects of Glycoprotein IIb/IIIa Inhibitors. Risk C: Monitor
Heparin: Nonsteroidal Anti-Inflammatory Agents (Nonselective) may increase anticoagulant effects of Heparin. Risk C: Monitor
Heparins (Low Molecular Weight): Nonsteroidal Anti-Inflammatory Agents (Nonselective) may increase anticoagulant effects of Heparins (Low Molecular Weight). Risk C: Monitor
Herbal Products with Anticoagulant/Antiplatelet Effects: May increase antiplatelet effects of Agents with Antiplatelet Effects. Risk C: Monitor
HydrALAZINE: Nonsteroidal Anti-Inflammatory Agents may decrease antihypertensive effects of HydrALAZINE. Risk C: Monitor
Ibritumomab Tiuxetan: Agents with Antiplatelet Effects may increase antiplatelet effects of Ibritumomab Tiuxetan. Risk C: Monitor
Ibrutinib: Agents with Antiplatelet Effects may increase adverse/toxic effects of Ibrutinib. Specifically, the risk of bleeding and hemorrhage may be increased. Risk C: Monitor
Inotersen: Agents with Antiplatelet Effects may increase adverse/toxic effects of Inotersen. Specifically, the risk of bleeding may be increased. Risk C: Monitor
Ketorolac (Nasal): May increase adverse/toxic effects of Nonsteroidal Anti-Inflammatory Agents. Risk X: Avoid
Ketorolac (Systemic): Nonsteroidal Anti-Inflammatory Agents may increase adverse/toxic effects of Ketorolac (Systemic). Risk X: Avoid
Levothyroxine: Mefenamic Acid may decrease protein binding of Levothyroxine. Risk C: Monitor
Limaprost: May increase adverse/toxic effects of Agents with Antiplatelet Effects. Specifically, the risk of bleeding may be increased. Risk C: Monitor
Lithium: Nonsteroidal Anti-Inflammatory Agents may increase serum concentration of Lithium. Management: Consider reducing the lithium dose when initiating a NSAID. Monitor for increased lithium therapeutic/toxic effects if a NSAID is initiated/dose increased, or decreased effects if a NSAID is discontinued/dose decreased. Risk D: Consider Therapy Modification
Loop Diuretics: Nonsteroidal Anti-Inflammatory Agents may decrease diuretic effects of Loop Diuretics. Loop Diuretics may increase nephrotoxic effects of Nonsteroidal Anti-Inflammatory Agents. Management: Monitor for evidence of kidney injury or decreased therapeutic effects of loop diuretics with concurrent use of an NSAID. Consider avoiding concurrent use in CHF or cirrhosis. Concomitant use of bumetanide with indomethacin is not recommended. Risk D: Consider Therapy Modification
Macimorelin: Coadministration of Nonsteroidal Anti-Inflammatory Agents and Macimorelin may alter diagnostic results. Risk X: Avoid
MetFORMIN: Nonsteroidal Anti-Inflammatory Agents may increase adverse/toxic effects of MetFORMIN. Risk C: Monitor
Methotrexate: Nonsteroidal Anti-Inflammatory Agents may increase serum concentration of Methotrexate. Management: Avoid coadministration of higher dose methotrexate (such as that used for the treatment of oncologic conditions) and NSAIDs. Use caution if coadministering lower dose methotrexate and NSAIDs. Risk D: Consider Therapy Modification
Methoxsalen (Systemic): Photosensitizing Agents may increase photosensitizing effects of Methoxsalen (Systemic). Risk C: Monitor
Methoxyflurane: Nonsteroidal Anti-Inflammatory Agents may increase nephrotoxic effects of Methoxyflurane. Risk X: Avoid
Mifamurtide: Nonsteroidal Anti-Inflammatory Agents may decrease therapeutic effects of Mifamurtide. Risk X: Avoid
Miscellaneous Antiplatelets: Agents with Antiplatelet Effects may increase antiplatelet effects of Miscellaneous Antiplatelets. Risk C: Monitor
Nadroparin: Nonsteroidal Anti-Inflammatory Agents (Nonselective) may increase anticoagulant effects of Nadroparin. Management: Coadministration of NSAIDs and nadroparin is not recommended due to an increased risk of bleeding. If coadministration is required, monitor patients closely for clinical and laboratory signs of bleeding. Risk D: Consider Therapy Modification
Naftazone: May increase antiplatelet effects of Nonsteroidal Anti-Inflammatory Agents. Risk C: Monitor
Nonsteroidal Anti-Inflammatory Agents (Topical): Nonsteroidal Anti-Inflammatory Agents (Topical) may increase adverse/toxic effects of Nonsteroidal Anti-Inflammatory Agents. Specifically, the risk of gastrointestinal (GI) toxicity is increased. Management: Coadministration of systemic nonsteroidal anti-inflammatory drugs (NSAIDs) and topical NSAIDs is not recommended. If systemic NSAIDs and topical NSAIDs, ensure the benefits outweigh the risks and monitor for increased NSAID toxicities. Risk D: Consider Therapy Modification
Nonsteroidal Anti-Inflammatory Agents: May increase adverse/toxic effects of Nonsteroidal Anti-Inflammatory Agents. Specifically, the risk for gastrointestinal toxicity is increased. Risk X: Avoid
Obinutuzumab: Agents with Antiplatelet Effects may increase adverse/toxic effects of Obinutuzumab. Specifically, the risk of bleeding may be increased. Management: Consider avoiding coadministration of obinutuzumab and agents with antiplatelet effects, especially during the first cycle of obinutuzumab therapy. Risk D: Consider Therapy Modification
Omacetaxine: Nonsteroidal Anti-Inflammatory Agents may increase adverse/toxic effects of Omacetaxine. Specifically, the risk for bleeding-related events may be increased. Risk C: Monitor
Pentosan Polysulfate Sodium: Agents with Antiplatelet Effects may increase adverse/toxic effects of Pentosan Polysulfate Sodium. Specifically, the risk of hemorrhage may be increased. Risk C: Monitor
Phenylbutazone: May increase adverse/toxic effects of Nonsteroidal Anti-Inflammatory Agents. Risk X: Avoid
Pirtobrutinib: May increase antiplatelet effects of Agents with Antiplatelet Effects. Risk C: Monitor
Polyethylene Glycol-Electrolyte Solution: Nonsteroidal Anti-Inflammatory Agents may increase nephrotoxic effects of Polyethylene Glycol-Electrolyte Solution. Risk C: Monitor
Porfimer: Photosensitizing Agents may increase photosensitizing effects of Porfimer. Risk X: Avoid
Potassium Salts: Nonsteroidal Anti-Inflammatory Agents may increase hyperkalemic effects of Potassium Salts. Risk C: Monitor
Potassium-Sparing Diuretics: Nonsteroidal Anti-Inflammatory Agents may increase hyperkalemic effects of Potassium-Sparing Diuretics. Nonsteroidal Anti-Inflammatory Agents may decrease antihypertensive effects of Potassium-Sparing Diuretics. Risk C: Monitor
PRALAtrexate: Nonsteroidal Anti-Inflammatory Agents may increase serum concentration of PRALAtrexate. More specifically, NSAIDS may decrease the renal excretion of pralatrexate. Management: Avoid coadministration of pralatrexate with nonsteroidal anti-inflammatory drugs (NSAIDs). If coadministration cannot be avoided, closely monitor for increased pralatrexate serum levels or toxicity. Risk D: Consider Therapy Modification
Probenecid: May increase serum concentration of Nonsteroidal Anti-Inflammatory Agents. Risk C: Monitor
Prostaglandins (Ophthalmic): Nonsteroidal Anti-Inflammatory Agents may decrease therapeutic effects of Prostaglandins (Ophthalmic). Nonsteroidal Anti-Inflammatory Agents may also enhance the therapeutic effects of Prostaglandins (Ophthalmic). Risk C: Monitor
Quinolones: Nonsteroidal Anti-Inflammatory Agents may increase neuroexcitatory and/or seizure-potentiating effects of Quinolones. Nonsteroidal Anti-Inflammatory Agents may increase serum concentration of Quinolones. Risk C: Monitor
Salicylates: Nonsteroidal Anti-Inflammatory Agents (Nonselective) may increase adverse/toxic effects of Salicylates. An increased risk of bleeding may be associated with use of this combination. Risk X: Avoid
Selective Serotonin Reuptake Inhibitor: May increase antiplatelet effects of Nonsteroidal Anti-Inflammatory Agents (Nonselective). Nonsteroidal Anti-Inflammatory Agents (Nonselective) may decrease therapeutic effects of Selective Serotonin Reuptake Inhibitor. Management: Consider alternatives to NSAIDs. Monitor for evidence of bleeding and diminished antidepressant effects. It is unclear whether COX-2-selective NSAIDs reduce risk. Risk D: Consider Therapy Modification
Selumetinib: May increase antiplatelet effects of Agents with Antiplatelet Effects. Risk C: Monitor
Serotonin/Norepinephrine Reuptake Inhibitor: May increase antiplatelet effects of Nonsteroidal Anti-Inflammatory Agents (Nonselective). Risk C: Monitor
Sincalide: Drugs that Affect Gallbladder Function may decrease therapeutic effects of Sincalide. Management: Consider discontinuing drugs that may affect gallbladder motility prior to the use of sincalide to stimulate gallbladder contraction. Risk D: Consider Therapy Modification
Sodium Phosphates: May increase nephrotoxic effects of Nonsteroidal Anti-Inflammatory Agents. Specifically, the risk of acute phosphate nephropathy may be enhanced. Risk C: Monitor
Sulprostone: Nonsteroidal Anti-Inflammatory Agents may decrease therapeutic effects of Sulprostone. Risk X: Avoid
Tacrolimus (Systemic): Nonsteroidal Anti-Inflammatory Agents may increase nephrotoxic effects of Tacrolimus (Systemic). Risk C: Monitor
Tenofovir Products: Nonsteroidal Anti-Inflammatory Agents may increase nephrotoxic effects of Tenofovir Products. Management: Seek alternatives to these combinations whenever possible. Avoid use of tenofovir with multiple NSAIDs or any NSAID given at a high dose due to a potential risk of acute renal failure. Diclofenac appears to confer the most risk. Risk D: Consider Therapy Modification
Tenoxicam: May increase adverse/toxic effects of Nonsteroidal Anti-Inflammatory Agents. Risk X: Avoid
Thiazide and Thiazide-Like Diuretics: Nonsteroidal Anti-Inflammatory Agents may decrease therapeutic effects of Thiazide and Thiazide-Like Diuretics. Thiazide and Thiazide-Like Diuretics may increase nephrotoxic effects of Nonsteroidal Anti-Inflammatory Agents. Risk C: Monitor
Thrombolytic Agents: Agents with Antiplatelet Effects may increase adverse/toxic effects of Thrombolytic Agents. Specifically, the risk of bleeding may be increased. Risk C: Monitor
Tipranavir: May increase antiplatelet effects of Agents with Antiplatelet Effects. Risk C: Monitor
Tolperisone: Nonsteroidal Anti-Inflammatory Agents may increase adverse/toxic effects of Tolperisone. Specifically, the risk of hypersensitivity reactions may be increased. Tolperisone may increase therapeutic effects of Nonsteroidal Anti-Inflammatory Agents. Risk C: Monitor
Tricyclic Antidepressants: May increase antiplatelet effects of Nonsteroidal Anti-Inflammatory Agents. Tricyclic Antidepressants may increase adverse/toxic effects of Nonsteroidal Anti-Inflammatory Agents. Specifically, the risk of major adverse cardiac events (MACE), hemorrhagic stroke, ischemic stroke, and heart failure may be increased. Risk C: Monitor
Vancomycin: Nonsteroidal Anti-Inflammatory Agents may increase serum concentration of Vancomycin. Risk C: Monitor
Verteporfin: Photosensitizing Agents may increase photosensitizing effects of Verteporfin. Risk C: Monitor
Vitamin E (Systemic): May increase antiplatelet effects of Agents with Antiplatelet Effects. Risk C: Monitor
Vitamin K Antagonists: Nonsteroidal Anti-Inflammatory Agents (Nonselective) may increase anticoagulant effects of Vitamin K Antagonists. Management: Consider alternatives to this combination when possible. If the combination must be used, monitor coagulation status closely and advise patients to promptly report any evidence of bleeding or bruising. Risk D: Consider Therapy Modification
Volanesorsen: May increase antiplatelet effects of Agents with Antiplatelet Effects. Risk C: Monitor
Zanubrutinib: May increase antiplatelet effects of Agents with Antiplatelet Effects. Risk C: Monitor
Nonsteroidal anti-inflammatory drugs may delay or prevent rupture of ovarian follicles. This may be associated with infertility that is reversible upon discontinuation of the medication. Consider discontinuing use in patients having difficulty conceiving or those undergoing investigation of fertility.
Mefenamic acid crosses the placenta (Mackenzie 1985).
The use of nonsteroidal anti-inflammatory drugs (NSAIDs) close to conception may be associated with an increased risk of miscarriage due to cyclooxygenase-2 inhibition interfering with implantation (Bermas 2014; Bloor 2013).
Birth defects have been observed following in utero NSAID exposure in some studies; however, data are conflicting (Bloor 2013). Nonteratogenic effects, including prenatal constriction of the ductus arteriosus, persistent pulmonary hypertension of the newborn, oligohydramnios, necrotizing enterocolitis, renal dysfunction or failure, and intracranial hemorrhage have been observed in the fetus/neonate following in utero NSAID exposure (Bermas 2014; Bloor 2013). Maternal NSAID use may cause fetal renal dysfunction leading to oligohydramnios. Although rare, this may occur as early as 20 weeks' gestation and is more likely to occur with prolonged maternal use. Oligohydramnios may be reversible following discontinuation of the NSAID (Dathe 2019; FDA 2020). In addition, nonclosure of the ductus arteriosus postnatally may occur and be resistant to medical management (Bermas 2014; Bloor 2013).
Avoid maternal use of NSAIDs beginning at ~20 weeks' gestation. If NSAID use is necessary between ~20 and 30 weeks' gestation, limit use to the lowest effective dose and shortest duration possible; consider ultrasound monitoring of amniotic fluid if treatment extends beyond 48 hours and discontinue the NSAID if oligohydramnios is found (FDA 2020). Because NSAIDs may cause premature closure of the ductus arteriosus, product labeling for mefenamic acid specifically states to avoid use starting at ~30 weeks' gestation.
Mefenamic acid may be present in breast milk.
• The distribution of mefenamic acid into breast milk was studied in 10 breastfeeding mothers. Patients were given mefenamic acid 500 mg orally, followed by 250 mg 3 times/day once oral medications could be tolerated. Dosing continued through postpartum day 4. Maternal serum and breast milk samples were collected simultaneously 2 hours after the first dose on days 2, 3, and 4. Serum and urine samples were collected from breastfed infants 1 hour after the last dose on day 4. Mean maternal serum samples ranged from 0.91 to 0.97 mcg/mL (range: 0.1 to 3.6 mcg/mL). Mean mefenamic acid breast milk samples ranged from 0.13 to 0.21 mcg/mL (range: 0.03 to 0.66 mcg/mL). The total concentration of mefenamic acid and metabolites in breast milk was measured in 3 patients (7 samples available) and ranged from 0.62 to 1.99 mcg/mL. Mefenamic acid was measurable in infant serum and urine with mean concentrations of 0.08 mcg/mL and 9.8 mcg/mL, respectively (Buchanan 1968).
• Using a breast milk concentration of 0.66 mcg/mL, the estimated exposure of mefenamic acid to the breastfeeding infant would be 0.099 mg/kg/day, providing a relative infant dose (RID) of 0.92%, based on a weight-adjusted maternal dose of 750 mg/day (not including metabolites).
• In general, breastfeeding is considered acceptable when the RID is <10% (Anderson 2016; Ito 2000).
Nonopioid analgesics, including nonsteroidal anti-inflammatory drugs (NSAIDs), are preferred for breastfeeding patients who require pain control peripartum or for surgery outside of the postpartum period (ABM [Martin 2018]; ABM [Reece-Stremtan 2017]).
Due to the potential for serious adverse reactions in the breastfeeding infant, the manufacturer recommends a decision be made whether to discontinue breastfeeding or to discontinue the drug, considering the importance of treatment to the mother. Avoid maternal use of NSAIDs if the breastfeeding infant has platelet dysfunction, thrombocytopenia, or a ductal-dependent cardiac lesion (ABM [Martin 2018]; ABM [Reece-Stremtan 2017]; Bloor 2013).
CBC, chemistry profile, occult blood loss, and periodic liver function tests; renal function (urine output, serum BUN and creatinine); signs or symptoms of GI bleeding; blood pressure.
Reversibly inhibits cyclooxygenase-1 and 2 (COX-1 and 2) enzymes, which results in decreased formation of prostaglandin precursors; has antipyretic, analgesic, and anti-inflammatory properties.
Other proposed mechanisms not fully elucidated (and possibly contributing to the anti-inflammatory effect to varying degrees) include inhibiting chemotaxis, altering lymphocyte activity, inhibiting neutrophil aggregation/activation, and decreasing proinflammatory cytokine levels.
Absorption: Rapidly absorbed
Distribution: Vd: 1.06 L/kg
Protein binding: >90% to albumin
Metabolism: Hepatic via CYP2C9 to metabolites (activity not known)
Half-life elimination: ~2 hours
Time to peak: 2 to 4 hours
Excretion: Urine (~52%) and feces (~20%) as unchanged drug and metabolites
Altered kidney function: The potential exists for mefenamic acid metabolites to accumulate.
Hepatic function impairment: The potential exists for mefenamic acid metabolites to accumulate.