Common Use

Zantac is a blocker of H2-histamine receptors. The mechanism of action involves the blockade of histamine H2-receptors in parietal cells of the gastric mucous layer. This medication suppresses both day and night secretion of HCl (basal and stimulated), reduces gastric juices caused by stomach stretching from food intake, and counteracts the effects of hormones and biogenic stimulants such as gastrin, histamine, acetylcholine, pentagastrin, and caffeine.

Zantac decreases HCl levels in gastric juice with minimal impact on liver enzymes associated with cytochrome P450. It does not affect plasma gastrin concentration or mucus production but reduces pepsin activity.

Zantac is used to treat and prevent:

• Stomach and duodenal ulcers
• Gastrointestinal disorders caused by NSAIDs
• Heartburn
• Gastric juice hypersecretion
• Symptomatic ulcers
• Stress-induced ulcers
• Erosive esophagitis
• Reflux esophagitis
• Zollinger-Ellison syndrome

Dosage and Direction

Take Zantac orally with or without food. Dose adjustments are necessary for patients with severe liver or kidney dysfunction. This medication may also be administered intramuscularly (IM) or intravenously.

Precautions

The effervescent tablet form of Zantac may contain phenylalanine. Consult your doctor before use if you are pregnant, planning pregnancy, or breastfeeding. Zantac may increase the risk of pneumonia.

Contraindications

Zantac is contraindicated in cases of hypersensitivity or breastfeeding. Use with caution in patients with:

• Liver or kidney failure
• Liver cirrhosis
• Acute porphyria (including history)
• Children under 12 years old
• Pregnancy

Possible Side Effects

Common side effects of Zantac include:

• Constipation
• Diarrhea
• Fatigue
• Headache
• Insomnia
• Muscle pain
• Nausea
• Vomiting

Rare but serious side effects may include:

• Agitation
• Anemia
• Confusion
• Depression
• Easy bruising or bleeding
• Hallucinations
• Hair loss
• Irregular heartbeat
• Visual changes
• Jaundice

Drug Interactions

Zantac may interact with other substances:

• Antacids: Separate intake by 1-2 hours to avoid reduced absorption.
• Alcohol: May increase blood alcohol levels.
• Metoprolol: Increases AUC and serum concentration.
• Itraconazole/Ketoconazole: Slows absorption.

Missed Dose

If you miss a dose, take it as soon as you remember, unless it's close to your next scheduled dose. Never double the dose to compensate.

Overdose

Seek immediate medical help if an overdose is suspected. Symptoms include lack of coordination, light-headedness, or fainting.

Storage

Store Zantac in a dry, dark place at 15-30°C (59-86°F).

Disclaimer

This information provides a general overview and does not cover all possible directions, interactions, or precautions. Never use it for self-diagnosis or self-treatment. Always consult your healthcare provider for personalized advice. We disclaim liability for any inaccuracies or consequences arising from the use of this information.