GI Meds for Nausea, Vomiting & Diarrhea

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GI Medication discussion of anti-emetics (for nausea and vomiting) and anti-motility medications (for diarrhea).
Generally Safe to Fly (GO) Avoid (NO GO)
Antacids:
• Aluminum hydroxide (Maalox)
• Calcium carbonate (Tums)
• Magnesium hydroxide (Milk of Magnesia) Antacids:
• bismuth subsalicylate (Kaopectate, Pepto-Bismol)
• loperamide (Imodium)

Pepto-Bismol OK, Imodium not OK.

The FAA adds some wise precautions and rationale for banning loperamide. Loperamide should not be used during acute illness as it can cause dizziness. When taken daily for a chronic condition, it may require an FAA special issuance for pilots to use it routinely. It is also important to remember that GI illness can cause dehydration, cramps, and pain with increase in altitude -- this is relevant whether treated with approved OTC GI meds or not.

CAUTION: The FAA adds a precaution being careful not to mask the underlying symptoms. These warnings are also on the labels because underlying serious conditions such as cancer or ulcers could improve after these medications but chronic sufferers still need medical checkups and occasionally EGDs to more fully characterize the problem.

Disclaimer: Neither the FAA nor FlightPhysical.com will attempt to publish all-inclusive references. Online guidance does not replace medical advice from your PCP and/or AME. Most doctors are not AMEs, and your regular Primary Care Provider (PCP) or specialist will know more about you and/or your specific medical condition than an AME, but is probably untrained or unfamiliar with aviation medicine. Follow 14 CFR 61.53 (duty to self-ground when ill) for your safety and that of your passengers. Don't fly after taking a new medication for the first time until 48 hours have past without side effects. When in doubt - DO NOT FLY.
FAA AME Guide Dec 2025 version and FAA.gov