Cimetidine: what it is for, how to use it and dosage

Cimetidine is a medicine indicated for the treatment of ulcers in the stomach or intestine, and other problems related to excess acid in the stomach, such as heartburn, gastroesophageal reflux or peptic esophagitis, as it works by reducing the production of acid in the stomach

This medicine can be found in pharmacies or drugstores, in the form of 200 mg or 400 mg tablets, as a generic or under the trade name Tagamet. Furthermore, cimetidine can be found in hospitals, in the form of an injection ampoule, for application directly into the muscle or vein, carried out by nurses, under medical supervision.

Cimetidine should only be used under medical advice, in the doses and for the duration of treatment advised by the doctor.

What is it for

Cimetidine is indicated for the treatment of:

• Ulcers in the stomach or intestine;
• Prevention of bleeding from ulcers;
• Peptic esophagitis;
• Excessive acidity in the stomach, which can cause bleeding;
• Heartburn, caused by excess acid in the stomach;
• Gastroesophageal reflux;
• Zollinger-Ellison syndrome;
• Systemic mastocytosis;
• Short bowel syndrome in which there is loss of fluid or difficulty in absorbing it.

Furthermore, cimetidine can be indicated before surgery, to reduce stomach acidity and prevent pneumonia caused by aspiration of gastric contents, known as Mendelson syndrome.

How to use and dosage

The way to use cimetidine varies depending on its presentation and includes:

1. Cimetidine tablets

Cimetidine tablets can be found in different doses, 200 mg or 400 mg, and must be taken orally, with a glass of water, before or after a meal, at times established by the doctor.

The dosage of cimetidine tablets for adults varies according to the condition being treated and includes:

• Ulcer in the stomach or intestine: the normally recommended dose is 800 mg, in a single dose, at night, before bed, as per medical advice. Furthermore, it may also be recommended by your doctor to divide the total dose into two, taking 1 tablet of 400 mg, twice a day, at breakfast and at bedtime;
• Gastroesophageal reflux: the normally recommended doses are 1 tablet of 400 mg, 4 times a day, with meals and at bedtime, for approximately 4 to 8 weeks of treatment, according to medical advice;
• Peptic esophagitis: the normally recommended dose is 1 tablet of 400 mg, twice a day, for approximately 2 weeks of treatment, as per medical advice.

Cimetidine doses can be changed by the doctor according to the response to treatment. Furthermore, the treatment time must be guided by the doctor, according to the condition to be treated and the severity of the symptoms.

2. Injectable cimetidine

Injectable cimetidine 150 mg/mL must be applied directly to the vein or gluteal muscle, by nurses in hospitals, under medical supervision.

The dosage of injectable cimetidine must be guided by the doctor and varies according to the condition being treated.

Possible side effects

The most common side effects of cimetidine are headache, dizziness, diarrhea, muscle pain, tiredness, or allergic skin reactions, such as the formation of blisters on the skin.

Additionally, although less common, cimetidine may cause breast enlargement or tenderness, milk production from the breasts, or sexual impotence.

Cimetidine can also cause serious side effects that should be reported immediately to your doctor, such as difficulty swallowing, blood in the stool or stool that looks like coffee grounds, coughing or vomiting blood, sadness, depression, hallucinations, mental confusion, increased heartbeat or liver inflammation.

Who shouldn’t use

Cimetidine should not be used by pregnant or breastfeeding women, or by people who have asthma attacks, heart disease, malignant gastric ulcers, or people who are allergic to the components of the formula or who are being treated with the drug dofetilide, indicated for treat cardiac arrhythmia.

Furthermore, this remedy should be used with caution by people who have kidney or liver problems.

Cimetidine in tablet form should not be used by children under 1 year of age.

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