H2 Blocker (Antacid/Acid Reducer)
Last reviewed June 2026
Who is this for?
Cimetidine is a medicine that reduces the amount of acid your stomach produces, helping to heal and prevent ulcers and relieve heartburn.
Blocks H2 histamine receptors on gastric parietal cells, inhibiting gastric acid secretion and reducing intragastric pH. This decreases acid-related damage to the gastric mucosa and promotes healing of peptic ulcers.
Available Over The Counter
Get this from any pharmacy or chemist — no prescription needed.
Explore this drug
For stomach ulcer, the usual adult dose is 400 mg taken twice daily (morning and night) or 800 mg taken once at bedtime. For heartburn or acid reflux, take 200 mg up to 4 times a day, usually with meals and at bedtime. You can take it with or without food, but taking it with food may help. Common brands in Nigeria include Cidtine 200 mg or 400 mg tablets, Gasrol, and Coco Cemitab.
If you miss a dose, take it as soon as you remember. But if it is almost time for your next dose, skip the missed one and continue your normal schedule. Do not take a double dose to make up for it.
Buy only from licensed pharmacies — avoid roadside sellers or open market drugs as fake cimetidine tablets are common in Nigeria. Do not use cimetidine for more than 2 weeks for heartburn without seeing a doctor, as it could be masking a more serious condition. Do not share your medication with others even if they have similar symptoms.
Cimetidine can increase the effects of blood thinners like warfarin, making bleeding more likely. It can also affect how your body handles theophylline (used for asthma) and some seizure medicines like phenytoin, so tell your doctor about all medicines you are taking. Avoid drinking alcohol while on cimetidine as it can worsen your stomach problem.
Check your specific combination
Is it safe to take Cimetidine with your other drugs?
Cimetidine is not recommended during pregnancy or breastfeeding unless your doctor says it is necessary — consult your doctor first.
Store in a cool, dry place away from direct sunlight and heat — Nigerian weather can be very hot, so avoid leaving it in your car or near a window. Keep the medicine in its original pack and away from children.
For information only — not medical advice. Always talk to a doctor or pharmacist before changing your medication.
Names this drug is sold under — especially in Nigerian and West African pharmacies
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Counterfeit Drug Warning
Fake drugs are a serious problem in Nigeria. Always buy from a registered pharmacy. If the packaging looks different from what is described above, do not use it.
Dispensing Cimetidine?
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