| Drug | Dose | Comments |
| Pyridoxine (vitamin B6)* | - 10 to 25 mg orally every 6 to 8 hours, PRN
| - Where the 10 mg tablet is unavailable, the 25 mg tablet can be used safely (splitting the tablet can be difficult).
|
| Antihistamines (H1 antagonists)¶ |
| Doxylamine-pyridoxine | - Two extended-release tablets orally at bedtime (each tablet contains doxylamine 10 mg and pyridoxine 10 mg).
- May increase to four tablets orally over the course of the day for more severe nausea (two tablets at bedtime, one tablet midmorning and one tablet in midafternoon if needed).
- A higher dose extended-release tablet containing 20 mg of doxylamine and 20 mg of pyridoxine is also available. One of these tablets is taken orally at bedtime, and if symptoms persist into the next day, one additional tablet is taken in the morning.
| - Taken daily (ie not PRN)
- Doxylamine and pyridoxine may be taken separately. Doxylamine is available in some over-the-counter sleeping pills (eg, Unisom Sleep Tabs) and as a prescription antihistamine chewable tablet (eg, Aldex AN): One-half of the 25 mg over-the-counter tablet or two chewable 5 mg tablets can be used off-label as an antiemetic. Pyridoxine (vitamin B-6) 25 mg, also available over-the-counter, can be taken three or four times per day along with 12.5 mg of doxylamine (the 10 mg dose of pyridoxine is not commercially available in the United States).
|
| Diphenhydramine | - 25 mg orally, IV, or IM every 4 to 6 hours or 50 mg orally, IV, or IM every 6 to 8 hours, PRN
| - If the patient is taking doxylamine, the total dose of diphenhydramine should not exceed 100 mg/day
|
| Dimenhydrinate | - 25 to 50 mg orally every 4 to 6 hours, PRN
- 50 mg IV or rectally (where available) every 4 to 6 hours, PRN
| - If the patient is taking doxylamine, the total dose of dimenhydrinate should not exceed 200 mg/day
|
| Dopamine antagonistsΔ |
| Metoclopramide | - 5 to 10 mg orally, IV, or IM every 6 to 8 hours, PRN
| - Preferably given 30 minutes before meals and bedtime
- Rarely causes tardive dyskinesia with prolonged use
|
| Promethazine | - 12.5 to 25 mg orally, rectally, or IM every 4 hours, PRN
| - When parenteral therapy is indicated, other parenteral antiemetics with less risk of tissue injury and other adverse effects are preferred (eg, prochlorperazine, diphenhydramine)
|
| Prochlorperazine | - 5 to 10 mg orally, IV, or IM every 6 to 8 hours, PRN
- 25 mg rectally twice daily, PRN
| |
| Chlorpromazine | - 25 to 50 mg IV or IM every 4 to 6 hours, PRN
- 10 to 25 mg orally every 4 to 6 hours, PRN
| - More frequent and severe adverse effects than other dopamine antagonists
- Typically reserved for refractory symptoms in patients who cannot tolerate steroids
|
| Serotonin antagonist |
| Ondansetron | - 4 to 8 mg orally or IV every 8 hours, PRN
| - An orally disintegrating tablet is available
- Potentially serious side effects◊
|
| Glucocorticoids |
| Methylprednisolone | - 125 mg IV followed by oral prednisone tapered over 2 weeks (40 mg on the first day, followed by 20 mg daily for three days, followed by 10 mg daily for three days, and then 5 mg daily for seven days)
- 16 mg orally every 8 hours for three days followed by an oral tapering regimen (halving the dose every three days over 2 weeks)
| - Reserved for refractory symptoms
- May be stopped abruptly if no response within 72 hours
|
| Hydrocortisone | - 100 mg IV every 8 hours for 72 hours followed by an IV tapering regimen (200 mg IV for two days and then 100 mg IV for another two days)
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