Pepcid AC Maximum Strength Side Effects
Generic name: famotidine
Note: This document contains side effect information about famotidine. Some of the dosage forms listed on this page may not apply to the brand name Pepcid AC Maximum Strength.
Some side effects of Pepcid AC Maximum Strength may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.
For the Consumer
Applies to famotidine: oral powder for reconstitution, oral tablet, oral tablet chewable
Get emergency medical help if you have any of these signs of an allergic reaction while taking famotidine (the active ingredient contained in Pepcid AC Maximum Strength) hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Stop using famotidine and call your doctor at once if you have a serious side effect such as:
easy bruising or bleeding;
fast or pounding heartbeat;
confusion, hallucinations, seizure;
numbness or tingly feeling; or
jaundice (yellowing of the skin or eyes).
Less serious side effects of famotidine may include:
nausea, vomiting, diarrhea, constipation;
dizziness, weakness, mood changes;
muscle cramps, joint pain.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.
For Healthcare Professionals
Applies to famotidine: compounding powder, intravenous solution, oral powder for reconstitution, oral tablet, oral tablet chewable, oral tablet disintegrating
Gastrointestinal side effects including diarrhea (1.7%) and constipation (1.2%) have been reported. Vomiting, nausea, abdominal discomfort, anorexia, and dry mouth have been reported infrequently. Hypergastrinemia of uncertain clinical significance has also been reported.
Nervous system side effects have included headache (1% to 4.7%) and dizziness (1.3%). Grand mal seizures, paresthesia, and somnolence have been reported infrequently. Lethargy, confusion, psychosis, and agitation have been reported. Delirium has been reported, which reversed upon drug withdrawal. Convulsions, in patients with impaired renal function, have been reported very rarely.
Confusion, lethargy, delirium, psychosis, agitation, seizures and somnolence have been reported, particularly in elderly patients and patients with multiple medical problems. The frequency of such reactions may be greater than previously believed. The FDA has accumulated 72 reported cases of such central nervous system reactions. All H2-blockers cross the blood-brain barrier and are found in the cerebrospinal fluid.
Hepatic side effects have included mild elevations of liver function tests. The clinical significance of these elevations is unknown. Jaundice and cholestatic jaundice have been reported infrequently. Cases of drug-induced hepatitis have also been reported.
Cardiovascular side effects have included decreases in stroke volume and cardiac output and may be clinically significant in patients with preexisting cardiac dysfunction. A variety of arrhythmias, including bradycardia, tachycardia, AV conduction defects (including AV block), and palpitations have also been reported rarely. Prolonged QT interval has been reported very rarely in patients with impaired renal function whose dose/dosing interval of famotidine (the active ingredient contained in Pepcid AC Maximum Strength) may not have been adjusted appropriately.
A 92-year-old male with a history of diabetes mellitus, hypertension, coronary artery disease, and pacemaker implantation for sick sinus syndrome experienced acquired long QT syndrome coincident with famotidine therapy. The patient was admitted with fever, periurethral abscess, and enterococcal sepsis. He was treated with several medications including famotidine. He was administered famotidine at 20 mg per nasogastric tube twice a day after admission. He developed an acute myocardial infarction 10 hours after famotidine therapy. The admission 12-lead electrocardiogram revealed a ventricular paced rhythm at a rate of 60 beats/min and a QTc of 439 ms. After two 20 mg doses of famotidine, the QTc became markedly prolonged at 618 ms. Four days after famotidine was discontinued, the QTc returned close to baseline at 445 ms.
Hypersensitivity side effects have infrequently included anaphylaxis, angioedema, orbital or facial edema, urticaria, rash, conjunctival infection, toxic epidermal necrolysis (very rare), erythema multiforme, and Stevens-Johnson syndrome (very rare).
Renal side effects have included rare cases of interstitial nephritis.
Endocrine side effects have included anti-androgen effects of reversible hyperprolactinemia and gynecomastia.
Dermatologic side effects have infrequently included alopecia, acne, pruritus, dry skin, and flushing. At least one case of contact dermatitis in a worker handling famotidine (the active ingredient contained in Pepcid AC Maximum Strength) has been reported.
A 22-year-old man reported painful, erythematous macules on his chest five days after starting famotidine. These progressed to hemorrhagic, painful erosions of the oral, conjunctival, and urogenital mucosal areas. A lymphocyte transformation test (LTT) was positive indicating an antigenic response to famotidine. The lesions completely resolved in 4 weeks after stopping famotidine and administering prednisolone, tobramycin, oxacillin, cefotaxime, and fluconazole.
Hematologic side effects including neutropenia have been reported. Rarely, reversible thrombocytopenia, agranulocytosis, pancytopenia, and leukopenia have been reported.
A case report of agranulocytosis eight days after the initiation of famotidine therapy has been reported in a 87-year-old male. After discontinuation of famotidine, initiation of empiric antibiotic use for the treatment of neutropenic fever, and administration of granulocyte-colony stimulating factor, the patient's white blood cell count and granulocyte count improved.
Respiratory side effects including bronchospasm and interstitial pneumonia have been reported infrequently.
Psychiatric side effects including depression, anxiety, insomnia, hallucinations, and decreased libido have been reported.
Musculoskeletal side effects have infrequently included musculoskeletal pain including muscle cramps and arthralgia.
Other side effects including tinnitus, fever, asthenia, fatigue, and taste disorder have been reported infrequently. At least one case of hyperpyrexia in association with famotidine (the active ingredient contained in Pepcid AC Maximum Strength) use has been reported.
More Pepcid AC Maximum Strength resources
- Famotidine Professional Patient Advice (Wolters Kluwer)
- famotidine Advanced Consumer (Micromedex) - Includes Dosage Information
- Famotidine Monograph (AHFS DI)
- famotidine MedFacts Consumer Leaflet (Wolters Kluwer)
- Pepcid Consumer Overview
- Pepcid Prescribing Information (FDA)
- Pepcid Injection Prescribing Information (FDA)
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