Brand names Acitak, Dyspamet, Galenamet, Peptimax, Phimetin, Tagamet, Ultec, Zita
Used in the following combined preparations Algitec, Tagamet Dual Action
GENERAL INFORMATION
Introduced in the 1970s, cimetidine Introduces the secretion of gastric acid and of pepsin, an enzyme that helps in the digestion of protein. By reducing levels of acid and pepsin, cimetidine promotes healing of ulcers in the stomach and duodenum it is also used for reflux oesophagitis, a condition that may cause acid stomach contents to flow part of the way up the oesophagus. Treatment is usually given in courses of four to eight weeks, with further short courses if symptoms recur.
Cimetidine also affects the actions of certain enzymes in the liver, where many drugs are broken down. It is therefore prescribed with caution to people who are receiving other drugs, particularly anticoagulants and anticonvulsants, whose levels need to be carefully controlled. Since cimetidine promotes healing of the stomach lining, it may mask the symptoms of stomach cancer and delay diagnosis.
It is therefore prescribed with caution.
INFORMATION FOR USERS
Your prescription is tailored for you. Do not alter dosage without checking with your doctor.
How taken
Tablets, liquid, injection.
Frequency and timing of doses
1-4 x daily (after meals and at bedtime).
Adult dosage range
800-2,400mg daily.
Onset of effect
Within 90 minutes.
Duration of action
2-6 hours.
Diet advice
None.
Storage
Keep in a closed container in a cool, dry place away from the reach of children.
Protect from light.
Missed dose
Do not take the missed dose. Take your next dose as usual.
Stopping the drug
If prescribed by your doctor, do not stop taking the drug without consulting him or her because symptoms may recur.
Exceeding the dose
An occasional unintentional extra dose is unlikely to be a cause for concern.
But if you notice any unusual symptoms, or if a large overdose has been taken, notify your doctor.
POSSIBLE ADVERSE EFFECTS
Adverse effects of cimetidine are uncommon. They are usually related to dosage level and almost always disappear when the drug is stopped.
INTERACTIONS
Benzodiazepines Cimetidine may cause an increase in blood levels of some of these drugs, leading to an increased risk of adverse effects.
Theophulline/aminophylline Cimetidine may increase the blood levels of these drugs and the dose may need to be
Anticonvulsant drugs Cimetidine may increase the blood levels of these drugs, and the dose may need to be reduced.
Anticoagulant drugs Cimetidine may increase the effect of these drugs. The dosage of anticoagulants may need to be reduced.
Beta blockers Cimetidine may increase the blood levels of these drugs.
QUICK REFERENCE
Drug group Anti-ulcer drug
Overdose danger rating Low
Dependence rating Low
Prescription needed No (some preparations)
Available as generic Yes
SPECIAL PRECAUTIONS
Be sure to tell your doctor if:
You have long-term liver or kidney problems.
You are taking other medications.
Pregnancy
Safety in pregnancy not established. Discuss with your doctor.
Breast-feeding
The drug passes into the breast milk, but at normal doses adverse effects on the baby are unlikely. Discuss with your doctor.
Infants and children
Reduced dose necessary.
Over 60
No special problems unless kidney function is reduced, in which case dosage is decreased.
Driving and hazardous work
Avoid such activities until you have learned how cimetidine affects you because the drug can cause dizziness and confusion.
Alcohol
Avoid. Alcohol may aggravate the underlying condition and counter the beneficial effects of cimetidine.
PROLONGED USE
Courses of longer than 8 weeks are not usually necessary.
