Famotidine, calcium carbonate, and magnesium hydroxide: Drug information

Drug Interactions

Acalabrutinib: Histamine H2 Receptor Antagonists may decrease the serum concentration of Acalabrutinib. Management: Give acalabrutinib capsules 2 hours before a histamine H2 receptor antagonist (H2RA). No action is required if acalabrutinib tablets are coadministered with H2RAs. Risk D: Consider therapy modification

Acalabrutinib: Antacids may decrease the serum concentration of Acalabrutinib. Management: Separate administration of acalabrutinib capsules from the administration of any antacid by at least 2 hours in order to minimize the potential for a significant interaction. Acalabrutinib tablets are not expected to interact with antacids. Risk D: Consider therapy modification

Alfacalcidol: May increase the serum concentration of Magnesium Salts. Management: Consider using a non-magnesium-containing antacid or phosphate-binding product in patients also receiving alfacalcidol. If magnesium-containing products must be used with alfacalcidol, serum magnesium concentrations should be monitored closely. Risk D: Consider therapy modification

Alpha-Lipoic Acid: Magnesium Salts may decrease the absorption of Alpha-Lipoic Acid. Alpha-Lipoic Acid may decrease the absorption of Magnesium Salts. Management: Separate administration of alpha-lipoic acid from that of any magnesium-containing compounds by several hours. If alpha-lipoic acid is given 30 minutes before breakfast, then administer oral magnesium-containing products at lunch or dinner. Risk D: Consider therapy modification

Alpha-Lipoic Acid: Calcium Salts may decrease the absorption of Alpha-Lipoic Acid. Alpha-Lipoic Acid may decrease the absorption of Calcium Salts. Management: Separate administration of alpha-lipoic acid from that of any calcium-containing compounds by several hours. If alpha-lipoic acid is given 30 minutes before breakfast, then administer oral calcium-containing products at lunch or dinner. Risk D: Consider therapy modification

Antipsychotic Agents (Phenothiazines): Antacids may decrease the absorption of Antipsychotic Agents (Phenothiazines). Risk C: Monitor therapy

Atazanavir: Antacids may decrease the absorption of Atazanavir. Management: Administer antacids 1 to 2 hours before or 2 hours after atazanavir to minimize the risk of a clinically significant interaction. Risk D: Consider therapy modification

Atazanavir: Histamine H2 Receptor Antagonists may decrease the serum concentration of Atazanavir. Management: Specific dose limitations and administration guidelines exist; consult full interaction monograph or atazanavir prescribing information. Risk D: Consider therapy modification

Baloxavir Marboxil: Polyvalent Cation Containing Products may decrease the serum concentration of Baloxavir Marboxil. Risk X: Avoid combination

Belumosudil: Antacids may decrease the serum concentration of Belumosudil. Management: Consider separating administration of belumosudil and antacids by 2 hours and monitor for reduced belumosudil efficacy. Risk D: Consider therapy modification

Bictegravir: Calcium Salts may decrease the serum concentration of Bictegravir. Management: Bictegravir, emtricitabine, and tenofovir alafenamide can be administered with calcium salts under fed conditions, but coadministration with or 2 hours after a calcium salt is not recommended under fasting conditions. Risk D: Consider therapy modification

Bictegravir: Polyvalent Cation Containing Products may decrease the serum concentration of Bictegravir. Management: Administer bictegravir under fasting conditions at least 2 hours before or 6 hours after polyvalent cation containing products. Coadministration of bictegravir with or 2 hours after most polyvalent cation products is not recommended. Risk D: Consider therapy modification

Bisacodyl: Antacids may diminish the therapeutic effect of Bisacodyl. Antacids may cause the delayed-release bisacodyl tablets to release drug prior to reaching the large intestine. Gastric irritation and/or cramps may occur. Management: Antacids should not be used within 1 hour before bisacodyl administration. Risk D: Consider therapy modification

Bismuth Subcitrate: Antacids may diminish the therapeutic effect of Bismuth Subcitrate. Management: Avoid administration of antacids within 30 minutes of bismuth subcitrate (tripotassium bismuth dicitrate) administration. Risk D: Consider therapy modification

Bisphosphonate Derivatives: Polyvalent Cation Containing Products may decrease the serum concentration of Bisphosphonate Derivatives. Management: Avoid administration of oral medications containing polyvalent cations within: 2 hours before or after tiludronate/clodronate/etidronate; 60 minutes after oral ibandronate; or 30 minutes after alendronate/risedronate. Risk D: Consider therapy modification

Bosutinib: Histamine H2 Receptor Antagonists may decrease the serum concentration of Bosutinib. Management: Administer histamine H2 receptor antagonists (H2RAs) more than 2 hours before or after bosutinib. Risk D: Consider therapy modification

Bosutinib: Antacids may decrease the serum concentration of Bosutinib. Management: Administer antacids more than 2 hours before or after bosutinib. Risk D: Consider therapy modification

Bromperidol: Antacids may decrease the absorption of Bromperidol. Risk C: Monitor therapy

Cabotegravir: Polyvalent Cation Containing Products may decrease the serum concentration of Cabotegravir. Management: Administer polyvalent cation containing products at least 2 hours before or 4 hours after oral cabotegravir. Risk D: Consider therapy modification

Calcitriol (Systemic): May increase the serum concentration of Magnesium Salts. Management: Consider using a non-magnesium-containing antacid or phosphate-binding product in patients also receiving calcitriol. If magnesium-containing products must be used with calcitriol, serum magnesium concentrations should be monitored closely. Risk D: Consider therapy modification

Calcium Acetate: Calcium Salts may enhance the adverse/toxic effect of Calcium Acetate. Risk X: Avoid combination

Calcium Channel Blockers: Calcium Salts may diminish the therapeutic effect of Calcium Channel Blockers. Risk C: Monitor therapy

Calcium Polystyrene Sulfonate: Laxatives (Magnesium Containing) may enhance the adverse/toxic effect of Calcium Polystyrene Sulfonate. More specifically, concomitant use of calcium polystyrene sulfonate with magnesium-containing laxatives may result in metabolic alkalosis or with sorbitol may result in intestinal necrosis. Management: Avoid concomitant use of calcium polystyrene sulfonate (rectal or oral) and magnesium-containing laxatives. Risk X: Avoid combination

Captopril: Antacids may decrease the serum concentration of Captopril. Risk C: Monitor therapy

Cardiac Glycosides: Calcium Salts may enhance the arrhythmogenic effect of Cardiac Glycosides. Risk C: Monitor therapy

Cefdinir: Antacids may decrease the absorption of Cefdinir. Management: Administer cefdinir 2 hours before or 2 hours after aluminum- or magnesium-containing antacids. Risk D: Consider therapy modification

Cefditoren: Histamine H2 Receptor Antagonists may decrease the serum concentration of Cefditoren. Risk X: Avoid combination

Cefditoren: Antacids may decrease the serum concentration of Cefditoren. Risk X: Avoid combination

Cefpodoxime: Histamine H2 Receptor Antagonists may decrease the serum concentration of Cefpodoxime. Risk C: Monitor therapy

Cefpodoxime: Antacids may decrease the serum concentration of Cefpodoxime. Risk C: Monitor therapy

Cefuroxime: Histamine H2 Receptor Antagonists may decrease the absorption of Cefuroxime. Risk X: Avoid combination

Chloroquine: Antacids may decrease the serum concentration of Chloroquine. Management: Separate the administration of antacids and chloroquine by at least 4 hours to minimize any potential negative impact of antacids on chloroquine bioavailability. Risk D: Consider therapy modification

Corticosteroids (Oral): Antacids may decrease the bioavailability of Corticosteroids (Oral). Management: Consider separating doses by 2 or more hours. Budesonide enteric coated tablets could dissolve prematurely if given with drugs that lower gastric acid, with unknown impact on budesonide therapeutic effects. Risk D: Consider therapy modification

Cysteamine (Systemic): Histamine H2 Receptor Antagonists may diminish the therapeutic effect of Cysteamine (Systemic). Risk C: Monitor therapy

Cysteamine (Systemic): Antacids may diminish the therapeutic effect of Cysteamine (Systemic). Risk C: Monitor therapy

Dabigatran Etexilate: Antacids may decrease the serum concentration of Dabigatran Etexilate. Management: Dabigatran etexilate Canadian product labeling recommends avoiding concomitant use with antacids for 24 hours after surgery. In other situations, administer dabigatran etexilate 2 hours prior to antacids. Monitor clinical response to dabigatran therapy. Risk D: Consider therapy modification

Dacomitinib: Histamine H2 Receptor Antagonists may decrease the serum concentration of Dacomitinib. Management: Administer dacomitinib at least 6 hours before or 10 hours after an histamine H2-receptor antagonist (H2RA). Risk D: Consider therapy modification

Dasatinib: Histamine H2 Receptor Antagonists may decrease the absorption of Dasatinib. Management: Antacids (taken 2 hours before or after dasatinib administration) can be used in place of H2-antagonists if some acid-reducing therapy is needed. Risk X: Avoid combination

Deferiprone: Polyvalent Cation Containing Products may decrease the serum concentration of Deferiprone. Management: Separate administration of deferiprone and oral medications or supplements that contain polyvalent cations by at least 4 hours. Risk D: Consider therapy modification

Delavirdine: Histamine H2 Receptor Antagonists may decrease the serum concentration of Delavirdine. Risk X: Avoid combination

Diacerein: Antacids may decrease the absorption of Diacerein. Risk C: Monitor therapy

Dichlorphenamide: May increase the serum concentration of Famotidine. Risk X: Avoid combination

DOBUTamine: Calcium Salts may diminish the therapeutic effect of DOBUTamine. Risk C: Monitor therapy

Dolutegravir: Calcium Salts may decrease the serum concentration of Dolutegravir. Management: Administer dolutegravir at least 2 hours before or 6 hours after oral calcium. Administer dolutegravir/rilpivirine at least 4 hours before or 6 hours after oral calcium salts. Alternatively, dolutegravir and oral calcium can be taken together with food. Risk D: Consider therapy modification

Dolutegravir: Magnesium Salts may decrease the serum concentration of Dolutegravir. Management: Administer dolutegravir at least 2 hours before or 6 hours after oral magnesium salts. Administer the dolutegravir/rilpivirine combination product at least 4 hours before or 6 hours after oral magnesium salts. Risk D: Consider therapy modification

Doxercalciferol: May enhance the hypermagnesemic effect of Magnesium Salts. Management: Consider using a non-magnesium-containing antacid or phosphate-binding product in patients also receiving doxercalciferol. If magnesium-containing products must be used with doxercalciferol, serum magnesium concentrations should be monitored closely. Risk D: Consider therapy modification

Eltrombopag: Polyvalent Cation Containing Products may decrease the serum concentration of Eltrombopag. Management: Administer eltrombopag at least 2 hours before or 4 hours after oral administration of any polyvalent cation containing product. Risk D: Consider therapy modification

Elvitegravir: Antacids may decrease the serum concentration of Elvitegravir. Management: Separate administration of aluminum and magnesium containing antacids and elvitegravir-containing products by at least 2 hours in order to minimize the risk for an interaction. Risk D: Consider therapy modification

Erdafitinib: Serum Phosphate Level-Altering Agents may diminish the therapeutic effect of Erdafitinib. Management: Avoid coadministration of serum phosphate level-altering agents with erdafitinib before initial dose increase period based on serum phosphate levels (Days 14 to 21). Risk D: Consider therapy modification

Erlotinib: Histamine H2 Receptor Antagonists may decrease the serum concentration of Erlotinib. Management: Avoid H2-antagonists in patients receiving erlotinib when possible. If concomitant treatment cannot be avoided, erlotinib should be dosed once daily, 10 hours after and at least 2 hours before H2-antagonist dosing. Risk D: Consider therapy modification

Erlotinib: Antacids may decrease the serum concentration of Erlotinib. Management: Separate the administration of erlotinib and any antacid by several hours in order to minimize the risk of a significant interaction. Risk D: Consider therapy modification

Estramustine: Calcium Salts may decrease the absorption of Estramustine. Management: Administer estramustine on an empty stomach, at least 1 hour before or 2 hours after the dose of an oral calcium supplement. If coadministered with calcium salts, monitor for decreased estramustine therapeutic effects. Risk D: Consider therapy modification

Fexofenadine: Antacids may decrease the serum concentration of Fexofenadine. Management: Separate the administration of fexofenadine and aluminum- or magnesium-containing antacids. Risk D: Consider therapy modification

Fosamprenavir: Histamine H2 Receptor Antagonists may decrease the serum concentration of Fosamprenavir. Cimetidine may also inhibit the metabolism of the active metabolite amprenavir, making its effects on fosamprenavir/amprenavir concentrations difficult to predict. Risk C: Monitor therapy

Fosinopril: Antacids may decrease the serum concentration of Fosinopril. Management: The US and Canadian fosinopril manufacturer labels recommend separating the doses of antacids and fosinopril by 2 hours. Risk D: Consider therapy modification

Gabapentin: Magnesium Salts may enhance the CNS depressant effect of Gabapentin. Specifically, high dose intravenous/epidural magnesium sulfate may enhance the CNS depressant effects of gabapentin. Magnesium Salts may decrease the serum concentration of Gabapentin. Management: Administer gabapentin at least 2 hours after use of a magnesium-containing antacid. Monitor patients closely for evidence of reduced response to gabapentin therapy. Monitor for CNS depression if high dose IV/epidural magnesium sulfate is used. Risk D: Consider therapy modification

Gefitinib: Histamine H2 Receptor Antagonists may decrease the serum concentration of Gefitinib. Management: Administer gefitinib at least 6 hours before or 6 hours after administration of a histamine H2 receptor antagonist (H2RA), and closely monitor clinical response to gefitinib. Risk D: Consider therapy modification

Gefitinib: Antacids may decrease the serum concentration of Gefitinib. Management: Administer gefitinib at least 6 hours before or 6 hours after administration of an antacid, and closely monitor clinical response to gefitinib. Risk D: Consider therapy modification

Hyoscyamine: Antacids may decrease the serum concentration of Hyoscyamine. Management: Administer immediate release and sublingual oral hyoscyamine before meals, and antacids after meals, when these agents are given in combination. Risk D: Consider therapy modification

Indinavir: Histamine H2 Receptor Antagonists may decrease the serum concentration of Indinavir. Risk C: Monitor therapy

Infigratinib: Histamine H2 Receptor Antagonists may decrease serum concentrations of the active metabolite(s) of Infigratinib. Histamine H2 Receptor Antagonists may decrease the serum concentration of Infigratinib. Management: Avoid coadministration of infigratinib with histamine receptor antagonists (H2RAs) or other gastric acid-lowering agents. If H2RAs cannot be avoided, administer infigratinib 2 hours before or 10 hours after administration of H2RAs. Risk D: Consider therapy modification

Infigratinib: Antacids may decrease serum concentrations of the active metabolite(s) of Infigratinib. Antacids may decrease the serum concentration of Infigratinib. Management: Avoid coadministration of infigratinib with antacids or other gastric acid-lowering agents. If antacids cannot be avoided, administer infigratinib 2 hours before or after administration of antacids. Risk D: Consider therapy modification

Iron Preparations: Antacids may decrease the absorption of Iron Preparations. Management: No action is likely necessary for the majority of patients who only use antacids intermittently or occasionally. Consider separating doses of oral iron and antacids in patients who require chronic use of both agents and monitor for reduced iron efficacy. Risk D: Consider therapy modification

Isoniazid: Antacids may decrease the absorption of Isoniazid. Risk C: Monitor therapy

Itraconazole: Antacids may decrease the serum concentration of Itraconazole. Antacids may increase the serum concentration of Itraconazole. Management: Administer Sporanox brand itraconazole at least 2 hours before or 2 hours after administration of any antacids. Exposure to Tolsura brand itraconazole may be increased by antacids; consider itraconazole dose reduction. Risk D: Consider therapy modification

Itraconazole: Histamine H2 Receptor Antagonists may increase the serum concentration of Itraconazole. Histamine H2 Receptor Antagonists may decrease the serum concentration of Itraconazole. Management: Administer Sporanox brand itraconazole at least 2 hours before or 2 hours after administration of any histamine H2 receptor antagonists (H2RAs). Exposure to Tolsura brand itraconazole may be increased by H2RAs; consider itraconazole dose reduction. Risk D: Consider therapy modification

Ketoconazole (Systemic): Antacids may decrease the serum concentration of Ketoconazole (Systemic). Management: Administer antacids at least 1 hour prior to, or 2 hours after, ketoconazole. Additionally, administer ketoconazole with an acidic beverage (eg, non-diet cola) and monitor patients closely for signs of inadequate clinical response to ketoconazole. Risk D: Consider therapy modification

Ketoconazole (Systemic): Histamine H2 Receptor Antagonists may decrease the serum concentration of Ketoconazole (Systemic). Management: Administer ketoconazole with an acidic beverage (eg, non-diet cola) and monitor for reduced efficacy if concomitant use with a H2RA is required. Increases in ketoconazole dose may be required. Risk D: Consider therapy modification

Lanthanum: Antacids may diminish the therapeutic effect of Lanthanum. Management: Administer antacid products at least 2 hours before or after lanthanum. Risk D: Consider therapy modification

Ledipasvir: Antacids may decrease the serum concentration of Ledipasvir. Management: Separate the administration of ledipasvir and antacids by 4 hours. Risk D: Consider therapy modification

Ledipasvir: Histamine H2 Receptor Antagonists may decrease the serum concentration of Ledipasvir. Management: Administer H2 receptor antagonist doses less than or comparable to famotidine 40 mg twice daily simultaneously or 12 hours prior to ledipasvir. The effect of administering H2 receptor antagonists at other time intervals is unknown and not recommended. Risk D: Consider therapy modification

Levoketoconazole: Histamine H2 Receptor Antagonists may decrease the absorption of Levoketoconazole. Risk X: Avoid combination

Levonadifloxacin: Calcium Salts may decrease the serum concentration of Levonadifloxacin. Risk X: Avoid combination

Levonadifloxacin: Magnesium Salts may decrease the serum concentration of Levonadifloxacin. Risk X: Avoid combination

Levonadifloxacin: Antacids may decrease the serum concentration of Levonadifloxacin. Risk X: Avoid combination

Levothyroxine: Magnesium Salts may decrease the serum concentration of Levothyroxine. Management: Separate administration of oral levothyroxine and oral magnesium salts by at least 4 hours. Risk D: Consider therapy modification

Mesalamine: Antacids may diminish the therapeutic effect of Mesalamine. Antacid-mediated increases in gastrointestinal pH may cause the premature release of mesalamine from specific sustained-release mesalamine products. Management: Avoid concurrent administration of antacids with the Apriso brand of mesalamine extended-release capsules. The optimal duration of dose separation is unknown. Other mesalamine products do not contain this interaction warning. Risk D: Consider therapy modification

Methenamine: Antacids may diminish the therapeutic effect of Methenamine. Management: Consider avoiding the concomitant use of medications that alkalinize the urine, such as antacids, and methenamine. Monitor for decreased therapeutic effects of methenamine if used concomitant with antacids. Risk D: Consider therapy modification

MiSOPROStol: Antacids may enhance the adverse/toxic effect of MiSOPROStol. More specifically, concomitant use with magnesium-containing antacids may increase the risk of diarrhea. Management: Avoid concomitant use of misoprostol and magnesium-containing antacids. In patients requiring antacid therapy, employ magnesium-free preparations. Monitor for increased adverse effects (e.g., diarrhea, dehydration). Risk X: Avoid combination

Multivitamins/Fluoride (with ADE): May increase the serum concentration of Calcium Salts. Calcium Salts may decrease the serum concentration of Multivitamins/Fluoride (with ADE). More specifically, calcium salts may impair the absorption of fluoride. Management: Avoid eating or drinking dairy products or consuming vitamins or supplements with calcium salts one hour before or after of the administration of fluoride. Risk D: Consider therapy modification

Multivitamins/Fluoride (with ADE): Magnesium Salts may decrease the serum concentration of Multivitamins/Fluoride (with ADE). Specifically, magnesium salts may decrease fluoride absorption. Management: To avoid this potential interaction separate the administration of magnesium salts from administration of a fluoride-containing product by at least 1 hour. Risk D: Consider therapy modification

Multivitamins/Minerals (with ADEK, Folate, Iron): Antacids may decrease the serum concentration of Multivitamins/Minerals (with ADEK, Folate, Iron). Specifically, antacids may decrease the absorption of orally administered iron. Management: Separate dosing of oral iron-containing multivitamins and antacids by as much time as possible to minimize impact of this interaction. Monitor for decreased therapeutic efficacy of oral iron preparations during coadministration. Risk D: Consider therapy modification

Mycophenolate: Magnesium Hydroxide may decrease the serum concentration of Mycophenolate. Management: Simultaneous administration of magnesium hydroxide antacids with the Myfortic brand of mycophenolic acid is specifically not recommended. Administer magnesium hydroxide at least 2 hours after a dose of the Cellcept brand of mycophenolate mofetil. Risk D: Consider therapy modification

Nelfinavir: Histamine H2 Receptor Antagonists may decrease serum concentrations of the active metabolite(s) of Nelfinavir. Histamine H2 Receptor Antagonists may decrease the serum concentration of Nelfinavir. Concentrations of the active M8 metabolite may also be reduced. Risk C: Monitor therapy

Neratinib: Histamine H2 Receptor Antagonists may decrease the serum concentration of Neratinib. Specifically, histamine H2 receptor antagonists may reduce neratinib absorption. Management: Administer neratinib at least 2 hours before or 10 hours after administration of a histamine H2 receptor antagonist to minimize the impact of this interaction. Risk D: Consider therapy modification

Neratinib: Antacids may decrease the serum concentration of Neratinib. Specifically, antacids may reduce neratinib absorption. Management: Separate the administration of neratinib and antacids by giving neratinib at least 3 hours after the antacid. Risk D: Consider therapy modification

Neuromuscular-Blocking Agents: Magnesium Salts may enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Risk C: Monitor therapy

Nilotinib: Histamine H2 Receptor Antagonists may decrease the serum concentration of Nilotinib. Management: The nilotinib dose should be given 10 hours after or 2 hours before the H2 receptor antagonist in order to minimize the risk of a significant interaction. Risk D: Consider therapy modification

Nilotinib: Antacids may decrease the serum concentration of Nilotinib. Management: Separate the administration of nilotinib and any antacid by at least 2 hours whenever possible in order to minimize the risk of a significant interaction. Risk D: Consider therapy modification

Nirogacestat: Histamine H2 Receptor Antagonists may decrease the serum concentration of Nirogacestat. Risk X: Avoid combination

Octreotide: Histamine H2 Receptor Antagonists may decrease the serum concentration of Octreotide. Risk C: Monitor therapy

Octreotide: Antacids may decrease the serum concentration of Octreotide. Risk C: Monitor therapy

PAZOPanib: Histamine H2 Receptor Antagonists may decrease the serum concentration of PAZOPanib. Risk X: Avoid combination

PenicillAMINE: Polyvalent Cation Containing Products may decrease the serum concentration of PenicillAMINE. Management: Separate the administration of penicillamine and oral polyvalent cation containing products by at least 1 hour. Risk D: Consider therapy modification

Pexidartinib: Antacids may decrease the serum concentration of Pexidartinib. Management: Administer pexidartinib at least 2 hours before or 2 hours after antacids. Risk D: Consider therapy modification

Pexidartinib: Histamine H2 Receptor Antagonists may decrease the serum concentration of Pexidartinib. Management: Administer pexidartinib 2 hours before or 10 hours after histamine H2 receptor antagonists. Risk D: Consider therapy modification

Phosphate Supplements: Antacids may decrease the absorption of Phosphate Supplements. Management: This applies only to oral phosphate administration. Separating administration of oral phosphate supplements from antacid administration by as long as possible may minimize the interaction. Risk D: Consider therapy modification

Phosphate Supplements: Calcium Salts may decrease the absorption of Phosphate Supplements. Management: This applies only to oral phosphate and calcium administration. Administering oral phosphate supplements as far apart from the administration of an oral calcium salt as possible may be able to minimize the significance of the interaction. Risk D: Consider therapy modification

Phosphate Supplements: Magnesium Salts may decrease the serum concentration of Phosphate Supplements. Management: Administer oral phosphate supplements as far apart from the administration of an oral magnesium salt as possible to minimize the significance of this interaction. Risk D: Consider therapy modification

Posaconazole: Histamine H2 Receptor Antagonists may decrease the serum concentration of Posaconazole. Risk C: Monitor therapy

Potassium Phosphate: Antacids may decrease the serum concentration of Potassium Phosphate. Management: Consider separating administration of antacids and oral potassium phosphate by at least 2 hours to decrease risk of a significant interaction. Risk D: Consider therapy modification

QuiNINE: Antacids may decrease the serum concentration of QuiNINE. Risk X: Avoid combination

Quinolones: Antacids may decrease the absorption of Quinolones. Of concern only with oral administration of quinolones. Management: Avoid concurrent administration of quinolones and antacids to minimize the impact of this interaction. Recommendations for optimal dose separation vary by specific quinolone; see full monograph for details. Risk D: Consider therapy modification

Quinolones: Calcium Salts may decrease the absorption of Quinolones. Of concern only with oral administration of both agents. Management: Consider administering an oral quinolone at least 2 hours before or 6 hours after the dose of oral calcium to minimize this interaction. Monitor for decreased therapeutic effects of quinolones during coadministration. Risk D: Consider therapy modification

Quinolones: Magnesium Salts may decrease the serum concentration of Quinolones. Management: Administer oral quinolones several hours before (4 h for moxi/pe/spar/enox-, 2 h for others) or after (8 h for moxi-, 6 h for cipro/dela-, 4 h for lome/pe/enox-, 3 h for gemi-, and 2 h for levo-, nor-, or ofloxacin or nalidixic acid) oral magnesium salts. Risk D: Consider therapy modification

Raltegravir: Magnesium Salts may decrease the serum concentration of Raltegravir. Management: Avoid the use of oral / enteral magnesium salts with raltegravir. No dose separation schedule has been established that adequately reduces the magnitude of interaction. Risk X: Avoid combination

Rilpivirine: Antacids may decrease the serum concentration of Rilpivirine. Management: Administer antacids at least 2 hours before or 4 hours after oral rilpivirine when used with most rilpivirine products. However, administer antacids at least 6 hours before or 4 hours after the rilpivirine/dolutegravir combination product. Risk D: Consider therapy modification

Rilpivirine: Histamine H2 Receptor Antagonists may decrease the serum concentration of Rilpivirine. Management: Administer histamine H2 receptor antagonists (H2RAs) at least 12 hours before or 4 hours after oral rilpivirine. Risk D: Consider therapy modification

Riociguat: Antacids may decrease the serum concentration of Riociguat. Management: Separate the administration of antacids and riociguat by at least 1 hour in order to minimize any potential interaction. Monitor clinical response to riociguat more closely in patients using this combination. Risk D: Consider therapy modification

Risedronate: Histamine H2 Receptor Antagonists may increase the serum concentration of Risedronate. This applies specifically to delayed-release risedronate. Risk X: Avoid combination

Rosuvastatin: Antacids may decrease the serum concentration of Rosuvastatin. Risk C: Monitor therapy

Roxadustat: Polyvalent Cation Containing Products may decrease the serum concentration of Roxadustat. Management: Administer roxadustat at least 1 hour after the administration of oral polyvalent cation containing products. Risk D: Consider therapy modification

Saquinavir: Histamine H2 Receptor Antagonists may increase the serum concentration of Saquinavir. Management: Consider alternatives to this combination for patients taking the Invirase formulation of saquinavir. No action beyond standard clinical care measures is required for patients taking the Fortovase formulation of saquinavir. Risk D: Consider therapy modification

Secretin: Histamine H2 Receptor Antagonists may diminish the diagnostic effect of Secretin. Specifically, use of H2-Antagonists may cause a hyperresponse in gastrin secretion in response to secretin stimulation testing, falsely suggesting gastrinoma. Management: Avoid concomitant use of histamine H2-antagonists (H2RAs) and secretin. Discontinue H2RAs at least 2 days prior to secretin administration. Risk D: Consider therapy modification

Selpercatinib: Histamine H2 Receptor Antagonists may decrease the serum concentration of Selpercatinib. Management: Coadministration of selpercatinib and H2 receptor antagonists should be avoided. If coadministration cannot be avoided, selpercatinib should be administered 2 hours before or 10 hours after H2 receptor antagonists. Risk D: Consider therapy modification

Selpercatinib: Antacids may decrease the serum concentration of Selpercatinib. Management: Coadministration of selpercatinib and antacids should be avoided. If coadministration cannot be avoided, selpercatinib should be administered 2 hours before or 2 hours after antacids. Risk D: Consider therapy modification

Sodium Polystyrene Sulfonate: Laxatives (Magnesium Containing) may enhance the adverse/toxic effect of Sodium Polystyrene Sulfonate. More specifically, concomitant use of sodium polystyrene sulfonate with magnesium-containing laxatives may result in metabolic alkalosis or with sorbitol may result in intestinal necrosis. Management: Avoid concomitant use of sodium polystyrene sulfonate (rectal or oral) and magnesium-containing laxatives. Risk X: Avoid combination

Sotalol: Antacids may decrease the serum concentration of Sotalol. Management: Avoid simultaneous administration of sotalol and antacids. Administer antacids 2 hours after sotalol. Risk D: Consider therapy modification

Sotorasib: Histamine H2 Receptor Antagonists may decrease the serum concentration of Sotorasib. Risk X: Avoid combination

Sparsentan: Histamine H2 Receptor Antagonists may decrease the serum concentration of Sparsentan. Risk X: Avoid combination

Strontium Ranelate: Magnesium Hydroxide may decrease the serum concentration of Strontium Ranelate. Management: Separate administration of strontium ranelate and magnesium hydroxide by at least 2 hours when possible, in order to minimize this interaction. Risk D: Consider therapy modification

Sucralfate: Antacids may diminish the therapeutic effect of Sucralfate. Management: Consider separating the administration of antacids and sucralfate by at least 30 minutes. Risk D: Consider therapy modification

Sulpiride: Antacids may decrease the serum concentration of Sulpiride. Management: Separate administration of antacids and sulpiride by at least 2 hours in order to minimize the impact of antacids on sulpiride absorption. Risk D: Consider therapy modification

Tacrolimus (Systemic): Magnesium Hydroxide may increase the serum concentration of Tacrolimus (Systemic). Magnesium Hydroxide may decrease the serum concentration of Tacrolimus (Systemic). Specifically, maximum concentration may decrease. Risk C: Monitor therapy

Tetracyclines: Antacids may decrease the absorption of Tetracyclines. Management: Separate administration of antacids and oral tetracycline derivatives by several hours when possible to minimize the extent of this potential interaction. Monitor for decreased therapeutic effects of tetracyclines. Risk D: Consider therapy modification

Tetracyclines: Magnesium Salts may decrease the absorption of Tetracyclines. Only applicable to oral preparations of each agent. Management: Avoid coadministration of oral magnesium salts and oral tetracyclines. If coadministration cannot be avoided, administer oral magnesium at least 2 hours before, or 4 hours after, oral tetracyclines. Monitor for decreased tetracycline therapeutic effects. Risk D: Consider therapy modification

Tetracyclines: Calcium Salts may decrease the serum concentration of Tetracyclines. Management: If coadministration of oral calcium with oral tetracyclines cannot be avoided, consider separating administration of each agent by several hours. Risk D: Consider therapy modification

Thiazide and Thiazide-Like Diuretics: May increase the serum concentration of Calcium Salts. Risk C: Monitor therapy

Thyroid Products: Calcium Salts may diminish the therapeutic effect of Thyroid Products. Management: Separate the doses of the thyroid product and the oral calcium supplement by at least 4 hours. Monitor for decreased therapeutic effects of thyroid products if an oral calcium supplement is initiated/dose increased. Risk D: Consider therapy modification

Trientine: Polyvalent Cation Containing Products may decrease the serum concentration of Trientine. Management: Avoid concomitant use of trientine and polyvalent cations. If oral iron supplements are required, separate the administration by 2 hours. For other oral polyvalent cations, give trientine 1 hour before, or 1 to 2 hours after the polyvalent cation. Risk D: Consider therapy modification

Unithiol: May diminish the therapeutic effect of Polyvalent Cation Containing Products. Risk X: Avoid combination

Velpatasvir: Antacids may decrease the serum concentration of Velpatasvir. Management: Separate administration of velpatasvir and antacids by at least 4 hours. Risk D: Consider therapy modification

Vitamin D Analogs: Calcium Salts may enhance the adverse/toxic effect of Vitamin D Analogs. Risk C: Monitor therapy