Famotidine

Medically Reviewed by Harshi Dhingra, M.D.

Last Reviewed: Jun 27, 2022

Warnings


What are the risks of taking famotidine (Pepcid AC)?


Famotidine can cause serious health problems, especially in certain high-risk patients. Please talk to your doctor or the pharmacist at your local pharmacy about other treatment options if these risks are concerning.

Some of the risks of famotidine include:
  • Serious medical conditions: Heartburn can be a symptom of a serious medical condition like stomach cancer. If, after 2 weeks of over-the-counter famotidine treatment, your symptoms do not improve, worsen, or keep coming back, please see a healthcare provider to ensure proper medical care.
  • CNS side effects: Elderly patients (age 65 and above) and people with kidney problems are at an increased risk of CNS side effects of famotidine, such as confusion, hallucinations, agitation, delirium, seizures, and irregular heartbeat. Impaired kidney function can raise the levels of famotidine in the body and increase the risk of these side effects. Talk to your doctor about the appropriate dose of famotidine if you have kidney disease. Seek immediate medical care if you experience any of these side effects.
Your doctor or pharmacist can prescribe other treatments to reduce stomach acid if you are at risk of complications from famotidine use.

What should I tell my doctor before starting famotidine (Pepcid AC)? 

Please tell your doctor if you have previously had an allergic reaction to famotidine (Pepcid AC), cimetidine (Tagamet), ranitidine (Zantac), nizatidine (Axid), or any other medication. Your pharmacist can give you a list of active and inactive ingredients in famotidine products. 

Also, give your doctor a complete list of your medications, including over-the-counter and prescription drugs, dietary supplements, and vitamins, as well as herbal products. This can help avoid serious interactions between famotidine and other medicines.

Tell your health care professional about all your medical conditions. Famotidine may not be suitable for people with certain health conditions. For example, be sure to tell your doctor if you have ever had trouble with swallowing, kidney disease, or have a condition called phenylketonuria.

Tell your doctor if you are pregnant, could be pregnant, plan to get pregnant, or breastfeeding. 

What precautions should I take while on famotidine (Pepcid AC)?

Keep all your appointments with your doctor if you are on prescription famotidine. If you are taking over-the-counter famotidine, do not take this medicine for longer than two weeks. If your symptoms do not get better, are worsening, or keep coming back, please seek care from a medical professional. Heartburn and GERD can be warning signs of more serious medical conditions.

Stop taking famotidine and call your doctor immediately for medical advice or go to the emergency room if you experience itching, hives, rash; swelling of the face, tongue, lips, throat, hands, or feet; or difficulty breathing or swallowing. Also, if you get black tarry stools or vomit up what looks like coffee grounds, contact your doctor immediately - these can be signs of a bleeding ulcer.

What are famotidine (Pepcid AC) interactions?

Taking famotidine with other medications may affect how the drug works or increase the risk of severe side effects. Your physician may choose a different medication for you, change the dose or frequency of one or both medicines, and/or monitor you carefully for side effects if there are known drug interactions. 

Using famotidine with the following medications is not recommended:

  • Sparfloxacin
  • Piperaquine
  • Mesoridazine
  • Bepridil
  • Cisapride
  • Pimozide
  • Ziprasidone
  • Terfenadine
  • Dronedarone
  • Saquinavir
  • Thioridazine
  • Dofetilide

There can be drug interactions between famotidine and the following medications:

  • Alendronate
  • Axitinib
  • Blessed thistle


  • Metformin

  • Cyanocobalamin

  • Ceftibuten

  • Devil's Claw


This list does not describe all possible famotidine interactions. Give your health care provider a complete list of your medications, including prescription drugs, over-the-counter medicines, dietary supplements, vitamins, and herbal remedies. Also, tell your health care provider if you smoke cigarettes, drink alcohol, or use illegal drugs because some of these substances can cause serious health complications when used with famotidine.