HISTAMINE H2 RECEPTOR ANTAGONISTS

Brand & Generic Names

Apo-Cimetidine	Pepcid
Axid	Peptol
CIMETIDINE	RANITIDINE
FAMOTIDINE	Tagamet
NIZATIDINE	Zantac
Novocimetine	Zantac-C

Basic Information

• Habit forming? No
• Prescription needed? Yes
• Available as generic? No
• Drug class: Histamine H2 antagonist

Uses

Treatment for duodenal ulcers and other conditions in which stomach produces excess hydrochloric acid.

Dosage & Usage Information

How to take:
Tablet or liquid--Swallow with liquid.
Oral suspension--Follow instructions on prescription.

When to take:
1 dose per day--take at bedtime.
2 or more doses per day--Take at the same times each day.

If you forget a dose:
Take as soon as you remember up to 2 hours late. If more than 2 hours, wait for next scheduled dose (don't double this dose).

What drug does:
Blocks histamine release so stomach secretes less acid.

Time lapse before drug works:
Begins in 30 minutes. May require several days to relieve pain.

Don't take with:
Any other medicine without consulting your doctor or pharmacist.

Overdose

SYMPTOMS:
Confusion, slurred speech, breathing difficulty, rapid heartbeat, delirium.

WHAT TO DO:

Overdose unlikely to threaten life. If person takes much larger amount than prescribed, call doctor, poison-control center or hospital emergency room for instructions.

Possible Adverse Reactions or Side Effects

Life-threatening:

In case of overdose, see Overdose section.

Common:

None expected.

Infrequent:

• Dizziness or headache, diarrhea.
• Diminished sex drive, unusual milk flow in females, hair loss.

Rare:

Confusion; rash, hives; sore throat, fever; slow, fast or irregular heartbeat; unusual bleeding or bruising; muscle cramps or pain; fatigue, weakness.
• Constipation.

Warnings & Precautions

Don't take if:
You are allergic to any histamine H2 antagonist.

Before you start, consult your doctor:

• If you plan to become pregnant while on medication.
• If you take aspirin. Aspirin may irritate stomach.

Over age 60:
Adverse reactions and side effects may be more frequent and severe than in younger persons.

Pregnancy:
Unknown effect. Consult doctor.

Breast-feeding:
Drug passes into milk. Avoid drug or discontinue nursing until you finish medicine. Consult doctor about maintaining milk supply.

Infants & children:
Not recommended.

Prolonged use:

• Possible liver damage.
• Talk to your doctor about the need for follow-up medical examinations or laboratory studies to check blood levels of vitamin B-12.

Skin & sunlight:
No problems expected.

Driving, piloting or hazardous work:
Don't drive or pilot aircraft until you learn how medicine affects you. Don't work around dangerous machinery. Don't climb ladders or work in high places. Danger increases if you drink alcohol or take medicine affecting alertness and reflexes, such as antihistamines, tranquilizers, sedatives, pain medicine, narcotics and mind-altering drugs.

Discontinuing:
Don't discontinue without consulting a doctor. Dose may require gradual reduction if you have taken drug for a long time. Doses of other drugs may also require adjustment.

Others:

• Patients on kidney dialysis--Take at end of dialysis treatment.
• May interfere with the accuracy of some medical tests.

Possible Interaction with Other Drugs

GENERIC NAME	COMBINED EFFECT
-------------------------	-----------------------
Alprazolam	Increased effect and toxicity of
	alprazolam.
Antacids*	Decreased absorption of histamine H2
	receptor antagonist.
Anticoagulants*, oral	Increased anticoagulant effect.
Anticholinergics*	Increased histamine H2 receptor
	antagonist effect.
Bupropion	Increased bupropion effect.
Carbamazepine	Increased effect and toxicity of
	carbamazepine.
Carmustine (BCNU)	Severe impairment of red blood cell
	production; some interference with
	white blood cell formation.
Chlordiazepoxide	Increased effect and toxicity of
	chlordiazepoxide.
Cisapride	Decreased histamine H2 receptor effect.
Diazepam	Increased effect and toxicity of
	diazepam.
Digitalis preparations*	Increased digitalis effect.
Encainide	Increased effect of histamine H2
	receptor antagonist.
Flurazepam	Increased effect and toxicity of
	flurazepam.
Glipizide	Increased effect and toxicity of
	glipizide.
Itraconazole	Decreased absorption of itraconazole.
Ketoconazole	Decreased ketoconazole absorption.
Labetalol	Increased antihypertensive effects.
Methadone	Increased effect and toxicity of
	methadone.
Metoclopramide	Decreased absorption of
	histamine H2 receptor antagonist.
Metoprolol	Increased effect and toxicity of
	metoprolol.
Metronidazole	Increased effect and toxicity of
	metronidazole.
Moricizine	Increased concentration of H2
	receptor antagonist in the blood.
Morphine	Increased effect and toxicity of
	morphine.
Nicardipine	Possible increased effect and toxicity
	of nicardipine.
Nimodipine	Possible increased effect and toxicity
	of nimodipine.
Paroxetine	Increased levels of paroxetine in blood.
Phenytoin	Increased effect and toxicity of
	phenytoin.
Procainamide	Increased effect and toxicity of
	procainamide.
Propafenone	Increased effect of both drugs and
	increased effect of toxicity.
Propranolol	Possible increased propranolol
	effect.
Quinidine	Increased quinidine effect.
Tacrine	Increased tacrine effect.
Tamoxifen	Decreased tamoxifen effect.
Theophylline	Increased theophylline effect.
Triazolam	Increased effect and toxicity of
	triazolam.
Verapamil	Increased effect and toxicity of
	verapamil.

Possible Interaction with Other Substances

INTERACTS WITH	COMBINED EFFECT
---------------	---------------
Alcohol:	No interactions expected, but
	alcohol may slow body's recovery.
	Avoid.
Milk.	Enhanced effectiveness. Small
	amounts useful for taking medication.
Caffeine drinks.	May increase acid secretion and
	delay healing.
Cocaine:	Decreased effect of histamine H2
	receptor antagonist.
Foods:	Enhanced effectiveness. Protein-
	rich foods should be eaten in
	moderation to minimize secretion
	of stomach acid.
Marijuana:	Increased chance of low sperm
	count. Marijuana may slow body's
	recovery. Avoid.
Tobacco:	Reversed effect of histamine H2
	receptor antagonist. Tobacco
	may slow body's recovery. Avoid.