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H2 Blockers


Over-the-counter H2 blockers such as Axid AR, Pepcid AC, Tagamet HB, and Zantac 75, are available in half the strength of prescription H2 blockers. They are used to prevent and relieve symptoms of heartburn and sour stomach. H2 blockers can be used up to 1 hour before eating to prevent symptoms, as well as when symptoms start. Although they don't work as quickly as antacids, their effects last longer.

Prescription-strength H2 blockers, such as Axid, Pepcid, Tagamet, and Zantac, can reduce moderate GERD symptoms and help heal mild-to-moderate esophagitis. They are very effective in preventing nighttime reflux. In addition, these medications provide symptom improvement within 6 weeks in more than 80% of people who have GERD. Although the standard dose is twice a day, you may need more frequent doses if you have severe symptoms associated with esophagitis or ulcers.

How H2 Blockers Work

H2 Receptor Blockers and Proton Pump Inhibitors H2 blockers decrease the production of stomach acid. They block histamine, or H2, from starting acid production in the stomach.

Possible Side Effects of H2 Blockers

Side effects vary among different types of H 2 blockers and are generally less common with the lower-dose, over-the-counter, or OTC, brands. If you experience any side effects, you should speak with your doctor. Some less common side effects include:

  • Axid and Axid AR may cause drowsiness. Less common side effects are increased sweating, fever, an allergic skin reaction, and changes in heartbeat.
  • Pepcid, Pepcid AC, Tagamet, and Tagamet HB can cause headaches in some people. Less common side effects include drowsiness, dizziness, skin rash, fever, diarrhea, and constipation.
  • Zantac and Zantac 75 may cause constipation, drowsiness, dizziness, skin rash, headache, nausea, vomiting, and diarrhea. Rarely, these medications may affect the heart or cause a fever.

Possible Drug Interactions with H2 Blockers

To help you avoid unnecessary side effects, use caution when taking H2 blockers with other drugs. Tell your doctor about all other drugs you are taking - it's a good idea to let your doctor see your other prescription containers.

Drugs to Avoid with H2 Blockers

Before you start taking an H2 blocker, tell your doctor if you take any of these drugs:

  • alcohol
  • antacids
  • antibiotics
  • anticoagulants
  • antifungal agents
  • anti-inflammatory agents
  • antitumor medications
  • asthma medications
  • depression medications
  • diabetic medications
  • drugs for Alzheimer's disease
  • drugs for bladder problems
  • drugs for intestinal parasites
  • drugs for nausea and dizziness
  • drugs given with anesthesia
  • drugs to improve blood flow
  • heart and blood pressure medications
  • iron deficiency supplements
  • local anesthetics
  • malaria medication
  • pain medications
  • seizure medication
  • tranquilizers

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