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Fluxid Side Effects

Generic name: famotidine

Medically reviewed by Last updated on Jul 24, 2023.

Note: This document contains side effect information about famotidine. Some dosage forms listed on this page may not apply to the brand name Fluxid.

Applies to famotidine: oral powder for suspension, oral tablet.

Serious side effects of Fluxid

Along with its needed effects, famotidine (the active ingredient contained in Fluxid) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking famotidine:


  • Anxiety
  • bleeding gums
  • blistering, peeling, or loosening of the skin
  • blood in the urine or stools
  • bloody, black, or tarry stools
  • cough
  • difficulty breathing
  • discouragement
  • fast, irregular, pounding, or racing heartbeat or pulse
  • feeling sad or empty
  • irritability
  • lack of appetite
  • loss of interest or pleasure
  • noisy breathing
  • pinpoint red spots on the skin
  • seeing, hearing, or feeling things that are not there
  • seizures
  • swelling around the eyes
  • tightness in the chest
  • trouble concentrating
  • trouble sleeping
  • unusual bleeding or bruising

Incidence not known

  • Agitation
  • blistering, peeling, or loosening of the skin
  • burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • chest pain
  • chills
  • clay-colored stools
  • dark urine
  • diarrhea
  • difficulty swallowing
  • dizziness or fainting
  • fever
  • general feeling of tiredness or weakness
  • headache
  • high fever
  • hives, itching, skin rash
  • hoarseness
  • joint or muscle pain
  • large, hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals
  • light-colored stools
  • lower back or side pain
  • nausea
  • painful or difficult urination
  • pale skin
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • red skin lesions, often with a purple center
  • red, irritated eyes
  • sore throat
  • sores, ulcers, or white spots in the mouth or on the lips
  • stomach pain
  • swollen glands
  • unpleasant breath odor
  • unusual tiredness or weakness
  • upper right abdominal pain
  • vomiting of blood
  • yellow eyes or skin

Other side effects of Fluxid

Some side effects of famotidine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

  • Difficulty having a bowel movement


  • Bad, unusual, or unpleasant (after) taste
  • bone or muscle pain
  • change in taste
  • continuing ringing or buzzing or other unexplained noise in the ears
  • decreased interest in sexual intercourse
  • difficulty in moving
  • dry mouth
  • dry skin
  • feeling of warmth
  • hearing loss
  • inability to have or keep an erection
  • lack or loss of strength
  • loss in sexual ability, desire, drive, or performance
  • muscle pain or stiffness
  • redness of the face, neck, arms and occasionally, upper chest
  • redness of the white part of the eyes
  • stomach discomfort
  • unusual drowsiness

For Healthcare Professionals

Applies to famotidine: compounding powder, intravenous solution, oral powder for reconstitution, oral tablet, oral tablet chewable, oral tablet disintegrating.


The most commonly reported side effects include headache, dizziness, constipation, and diarrhea.[Ref]


Common (1% to 10%): Constipation, diarrhea

Uncommon (0.1% to 1%): Nausea, vomiting, flatulence, dry mouth, abdominal discomfort or distension[Ref]

Nervous system

Convulsions occurred in patients with renal dysfunction.[Ref]

Common (1% to 10%): Headache, dizziness

Very rare (less than 0.01%): Paresthesia, somnolence, epileptic seizures, convulsion

Frequency not reported: Grand mal seizure, taste disorder[Ref]


Uncommon (0.1% to 1%): Rash, pruritus

Rare (0.01% to 0.1%): Urticaria, angioneurotic edema

Very rare (less than 0.01%): Alopecia, severe skin reactions, toxic epidermal necrolysis, Stevens-Johnson syndrome, epidermal necrolysis

Frequency not reported: Acne, dry skin, flushing[Ref]


Uncommon (0.1% to 1%): Fatigue

Frequency not reported: Asthenia, fatigue, facial/orbital edema, tinnitus[Ref]


Uncommon (0.1% to 1%): Loss of appetite

Frequency not reported: Anorexia[Ref]


Rare (0.01% to 0.1%): Thrombocytopenia, leukopenia, agranulocytosis, pancytopenia

Frequency not reported: Neutropenia[Ref]


Rare (0.01% to 0.1%): Intrahepatic cholestasis, jaundice, increased liver enzyme abnormalities (transaminases, gamma GT, alkaline phosphatase, bilirubin)

Frequency not reported: Cholestatic jaundice, hepatitis[Ref]


Rare (0.01% to 0.1%): Hypersensitivity reactions, anaphylaxis[Ref]


Rare (0.01% to 0.1%): Bronchospasm

Frequency not reported: Interstitial pneumonia[Ref]


Rare (0.01% to 0.1%): Arthralgia

Very rare (less than 0.01%): Muscle cramps

Frequency not reported: Rhabdomyolysis, musculoskeletal pain[Ref]


When patients obtained follow-up, psychic disturbances were found to be reversible.[Ref]

Very rare (less than 0.01%): Hallucinations, disorientation, confusion, anxiety, agitation, depression, reduced libido, insomnia

Frequency not reported: Psychic disturbances[Ref]


QT interval prolongation occurred in patients with renal dysfunction.[Ref]

Very rare (less than 0.01%): Chest tightness, prolonged QT interval

Frequency not reported: Arrhythmia, atrioventricular block, palpitation[Ref]


Very rare (less than 0.01%): Impotence[Ref]


Frequency not reported: Conjunctival injection[Ref]


Frequency not reported: Gynecomastia[Ref]

Frequently asked questions


1. Product Information. Pepcid (famotidine). Merck & Co., Inc. 2002.

2. Product Information. Pepcid AC (famotidine). Johnson and Johnson/Merck. 2001.

3. Cerner Multum, Inc. UK Summary of Product Characteristics.

4. Cerner Multum, Inc. Australian Product Information.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.