Pepzan - Dosage | Interactions | Side effects

Pepzan is a medicine that contains active ingredient famotidine and belongs to the group of H2 histamine-receptor blockers. It is used to treat all pathological conditions characterized by hypersecretion of gastric acid, including:

  • Stomach or duodenal ulcer (for short-term therapy only, up to 8 weeks)
  • Gastroesophageal reflux disease (GERD) characterized by the return of gastric contents into the esophagus causing heartburn and dysphagia (difficulty swallowing). Pepzan should only be used for short-term treatment (not more than 12 weeks).
  • Zollinger-Ellison syndrome.


Tell your doctor if you are allergic to the active ingredient - famotidine or similar medicines (for example, ranitidine, also known as Zantac). Kim al reported a case of anaphylactic reaction induced by this drug. If you notice difficulty breathing, swelling of the face, swelling of the tongue or skin rash, contact your physician immediately.

Since it can mask the symptoms of stomach or duodenal cancer, it is necessary to exclude cancer as a possible diagnosis before starting the therapy.

A case of acute interstitial nephritis induced by this drug has been reported. If you notice symptoms of kidney inflammation (pelvic pain, darker urine, painful urination and edema), contact your doctor immediately.

Dose adjustment is recommended in patients with impaired renal function.

Cases of severe and irreversible retinopathy followed by blurred vision have been reported. Histamine H2-receptors are present in the retina of the eye, and it is assumed that Pepzan binds to these receptors and decreases the blood supply to the eye, causing retinopathy. If you are experiencing blurred vision, you should contact your doctor immediately.

Cases of liver damage followed by hepatocellular jaundice have been reported. If you notice the signs and symptoms of liver damage (e.g. epigastric pain, loss of appetite and jaundice), you should contact your physician immediately. Monitoring of liver function is recommended especially if Pepzan is used for more than two months.

Pepzan, Pregnancy and Breastfeeding

Pepzan is detected in the milk of nursing mothers, and the use of this medication during breastfeeding is not recommended.

There are insufficient data on the Pepzan's use in human pregnancy, although animal studies have shown that this drug cause no harm to fetus.


Studies have shown that Pepzan inhibits gastric secretion by 94% if administered at bedtime, and by 83% if administered after breakfast, respectively. For this reason, it is best to take the tablet just before you go to bed.

The usual dose for stomach and duodenal ulcer is 40 mg once daily, while a lower dose (20 mg once daily) is recommended for GERD.

For the treatment of Zollinger-Ellison syndrome, the usual dose ranges from 20 to 160 mg, four times a day.


Pepzan reduces acidity, interferes with the absorption and reduces plasma levels of the following drugs:

  • Atazanavir (medication used to treat HIV infection). Pepzan reduces the effectiveness of this medicine in the treatment of HIV infection!
  • Dasatinib (medication used to treat acute lymphoblastic leukemia and chronic myeloid leukemia). Pepzan reduces the effectiveness of dasatinib in the treatment of leukemia!
  • Pazopanib (medication used to treat kidney cancer). Pepzan reduces the effectiveness of pazopanib in the treatment of cancer!

Also, it should not be used at the same time with the following drugs:

  • Antacids. These medications reduce the absorption of Pepzan tablets, therefore it should be taken 1-2 hours after taking an antacid.
  • Ketoconazole (antifungal medicine). Ketoconazole should be taken at least two hours before taking Pepzan tablets.
  • Probenecid. Simultaneous administration increases the concentration of Pepzan in the blood, therefore increases the risk of side effects.
  • Aminophylline and theophylline (medicines used to treat asthma). Pepzan can increase the concentration of these drugs in the blood and can cause nausea, insomnia and convulsions.
  • Naproxen (medication used to treat pain and inflammatory processes). Pepzan can cause the destruction of a coating that oblongs naproxen tablets which reduces their effectiveness.
  • Glimepiride (medication used to control blood sugar levels in diabetic patients). Pepzna increases the effects of glimepiride, which can cause hypoglycemia.
  • Entecavir (brand name: Enteclude). This medicine is used to treat hepatitis B infection. Concomitant administration leads to an increase in concentration of both, entecavir and Pepzan in the blood, which increases the risk of adverse effects.

Side effects

Adverse effects occur rarely. Possible side effects of Pepzan include:

  • Mild and transient increase in liver enzymes
  • Hepatocellular jaundice
  • Acute interstitial nephritis
  • Diarrhea
  • Constipation
  • Nausea
  • Dry mouth
  • Dizziness
  • Confusion
  • Anxiety
  • Retinopathy
  • Blurred vision
  • Palpitations
  • Arrhythmias
  • Atrioventricular block
  • Grand mal seizures
  • Toxic epidermal necrolysis and Steven-Johnson syndrome
  • Breast enlargement in men
  • Pruritus
  • Joint pain
  • Muscle cramps


  1. NCBI link
  2. Kouichi H, Kazunobu H, Toshio I. Famotidine-induced acute interstitial nephritis. Nephrol Dial Transplant. 1998. 13: 2636-38.
  3. Lee YC, Wang CC. Famotidine-induced retinopathy. Eye. 2006. 20: 260-3.
  4. Ament PW, Roth JD and Fox JC. Famotidine-Induced Mixed Hepatocellular Jaundice. Sage Journals. 1994. vol.28.
  5. FDA

Information on this website are provided for educational purposes only and are not intended for medical advice, diagnosis or treatment.

If you have any concerns or questions about your health, you should always consult with a physician or other health-care professional.