Famotidine, also known as Pepcid, is a histamine H 2 -receptor antagonist, also known as an H 2 -blocker, and an Antiulcer Agent. Pepcid is used to treat certain ulcers and prevent their return. They are also used to treat some conditions, like Zollinger-Ellison disease, in which the stomach produces too much acid. They work by decreasing the amount of acid produced by the stomach.
Be sure to tell your doctor of any allergies you have whether it is to medication or food, preservatives, or dyes. Tell your doctor immediately if you are, or become pregnant, or are breastfeeding, as it is unknown how Pepcid may affect your baby. Also tell your doctor of any other medications you are taking, including vitamins and supplements, and any medical conditions you may have.
It is very important that you take this medicine exactly as your doctor tells you to. If you miss a dose of this medicine, take it as soon as you remember, unless it is almost time for your next dose. Do NOT double doses.
Tell your doctor as soon as possible if any of the following side effects occur: abdominal pain; back, leg, or stomach pain; bleeding or crusting sores on lips; blistering, burning, redness, scaling, or tenderness of skin ; blisters on palms of hands and soles of feet; changes in vision or blurred vision; confusion; coughing or difficulty in swallowing; dark-colored urine; dizziness; fainting; fast, pounding, or irregular heartbeat; fever and/or chills; flu-like symptoms; general feeling of discomfort or illness; hives; inflammation of blood vessels; joint pain; light-colored stools; mood or mental changes, including anxiety, agitation, confusion, hallucinations, mental depression, nervousness, or severe mental illness; muscle cramps or aches; nausea, vomiting, or loss of appetite; pain; peeling or sloughing of skin; red or irritated eyes; shortness of breath; skin rash or itching; slow heartbeat; sore throat; sores, ulcers, or white spots on lips, in mouth, or on genitals; sudden difficult breathing; swelling of face, lips, mouth, tongue, or eyelids; swelling of hands or feet; swollen or painful glands; tightness in chest; troubled breathing; unusual bleeding or bruising; unusual tiredness or weakness; unusually slow or irregular breathing; wheezing; and yellow eyes or skin.
The active ingredient in PEPCID (famotidine) is a histamine H2-receptor antagonist. Famotidine is N′- (aminosulfonyl)-3- [[[2-[(diaminomethylene) amino] -4-thiazolyl]methyl]thio]propanimidamide. The empirical formula of famotidine is C8H15N7O2S3 and its molecular weight is 337.43. Each tablet for oral administration contains either 20 mg or 40 mg of famotidine and the following inactive ingredients: hydroxypropyl cellulose, hydroxypropyl methylcellulose, iron oxides, magnesium stearate, microcrystalline cellulose, corn starch, talc, and titanium dioxide. Each 5 mL of the oral suspension when prepared as directed contains 40 mg of famotidine and the following inactive ingredients: citric acid, flavors, microcrystalline cellulose and carboxymethylcellulose sodium, sucrose and xanthan gum. Added as preservatives are sodium benzoate 0.1%, sodium methylparaben 0.1%, and sodium propylparaben 0.02%.
Pepcid has the following structural formula: