BMA Concise Guide to Medicine & Drugs


Brand names Boots Heartburn Relief Tablets, Gavilast, Ranitic, Zantac

Used in the following combined preparations None


Drug group Anti-ulcer drug

Overdose danger rating Low

Dependence rating Low

Prescription needed No (tablets in limited quantities); Yes (other preparations)

Available as generic Yes


Ranitidine is an anti-ulcer drug of the antihistamine (H2) antagonist type (known as H2 blockers). It reduces acid production by the stomach, allowing ulcers to heal, and is usually given in courses lasting four to eight weeks, with further courses if symptoms recur. In combination with antibiotics, ranitidine may be used for ulcers caused by Helicobacter pylori infection. It may also be used to protect against ulcers in people taking NSAIDs, and to reduce the discomfort and ulceration of oesophagitis. In medical practice, ranitidine has been largely replaced by newer proton pump inhibitor anti-ulcer drugs, such as omeprazole. It is available over-the-counter for the short-term treatment of heartburn and indigestion in those over 16 years old. Unlike the similar drug cimetidine, ranitidine does not increase blood levels of other drugs such as anticoagulants and anticonvulsants. Most people experience no serious side effects during treatment. As ranitidine promotes healing of the stomach lining, there is a risk that it might mask stomach cancer. It is therefore prescribed only when this possibility has been ruled out.


Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor. For over-the-counter preparations, follow the instructions and call your doctor if symptoms worsen.

How taken/used Tablets, effervescent tablets, liquid, injection.

Frequency and timing of doses Once daily at bedtime or 2–4 x daily.

Adult dosage range 150mg–6g daily, depending on the condition being treated. Usual dose is 150mg twice daily.

Onset of effect Within 1 hour.

Duration of action 12 hours.

Diet advice None.

Storage Keep in original container at room temperature out of the reach of children. Protect from light.

Missed dose Take as soon as you remember. If your next dose is due within 3 hours, take a single dose now and skip the next.

Stopping the drug Do not stop the drug without consulting your doctor; 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.


The adverse effects of ranitidine are usually related to dosage level. The most common effects are heachache and dizziness. Less commonly, nausea, vomiting, constipation, or diarrhoea may occur. Discuss with your doctor if any of these are severe. Rarely, jaundice, agitation, or mental problems may occur; if so, consult your doctor. If you develop a sore throat or fever, contact your doctor immediately.


Ketoconazole Ranitidine may reduce the absorption of ketoconazole. Ranitidine should be taken at least 2 hours after ketoconazole.

Glipizide Ranitidine may increase the absorption of glipizide.

Sucralfate High doses (2g) of sucralfate may reduce the absorption of ranitidine. Sucralfate should be taken at least 2 hours after ranitidine.

Theophylline/aminophylline Ranitidine may increase blood levels of these drugs.


Be sure to consult your doctor or pharmacist before taking this drug if:

· You have long-term liver or kidney problems.

· You have porphyria.

· You are taking other medicines.

Pregnancy Safety in pregnancy not established. Discuss with your doctor.

Breast-feeding The drug passes into the breast milk and may affect the baby. Discuss with your doctor.

Infants and children Reduced dose necessary.

Over 60 No special problems.

Driving and hazardous work No known problems. Dizziness can occur in a very small proportion of patients.

Alcohol Avoid. Alcohol may aggravate your underlying condition and reduce the beneficial effects of this drug.


No problems expected.