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Cimetidine is used to treat excess stomach acid, such as in acid reflux disease (GERD) or Zollinger-Ellison syndrome. This drug is also used in the treatment of gastric ulcers, duodenal ulcers, or erosive esophagitis which is a complication of excess stomach acid.  

Cimetidine belongs to the class of H2 antagonist drugs. This drug works by decreasing the production of acid in the stomach, thereby reducing complaints due to excess stomach acid, such as heartburn, bloating, or nausea. In addition, reduced stomach acid will help heal wounds in the stomach or intestines.

Cimetidine trademarks: Cimetidine, Cimexol, Corsamet, Gastricon, Lexamet, Licimet, Licomet, Omekur, Sanmetidine, Selestidine, Tidifar, Ulcusan, and Vargumet.

What is Cimetidine

class H2 . antagonist
Category Prescription drugs
Benefit Treating conditions associated with excess stomach acid, such as Zollinger-Ellison syndrome and acid reflux disease ( GERD ), as well as treating gastric and duodenal ulcers
Consumed by Mature
Cimetidine for pregnant and lactating women Category B: Animal studies have not shown a risk to the fetus, but there are no controlled studies in pregnant women. Cimetidine is absorbed into breast milk. For breastfeeding mothers, do not take this medicine without consulting your doctor first.
Drug form Tablets and capsules

Precautions Before Taking Cimetidine

There are several things that need to be considered before undergoing treatment with cimetidine, including:

  • Do not take cimetidine if you are allergic to it, or to other H2 antagonist drugs, such as ranitidine or famotidine . Tell your doctor about any allergies you have.
  • Tell your doctor if you have or have ever had diabetes , HIV/AIDS, kidney disease , liver disease, lung disease, such as COPD , or other stomach disease, such as a tumor.
  • Talk to your doctor about using cimetidine if your acid reflux is accompanied by abdominal pain, nausea and vomiting, wheezing, unplanned weight loss, chest pain, or it's been going on for more than 3 months and doesn't improve.
  • Tell your doctor if you are taking other medications, including supplements and herbal products, to avoid possible drug interactions.
  • Tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding.
  • Immediately see a doctor if you experience an allergic reaction to the drug after taking cimetidine.

Dosage and Instructions for Use of Cimetidine

The following is the distribution of cimetidine doses in adult patients based on their intended use:

  • Zollinger-Ellison syndrome treatment : 300 mg or 400 mg, 4 times a day. Dosage can be increased if needed. The maximum dose is 2,400 mg per day.
  • Treat stomach acid disease or gastroesophageal reflux disease (GERD) : 400 mg, 4 times a day; or 800 mg, 2 times daily, taken for 4–12 weeks.
  • Treatment of stomach ulcers or duodenal ulcers : 800 mg per day at bedtime or 400 mg, 2 times a day. Treatment duration is 6 weeks for gastric ulcers and 4 weeks for duodenal ulcers. Maintenance dose: 400 mg at bedtime or 400 mg twice daily.
  • Treating short bowel syndrome or short bowel syndrome: 400 mg, 2 times a day. The dose can be increased according to the patient's body response to treatment.
  • Preventing gastrointestinal bleeding due to severe body conditions ( stress ulcers ): 200–400 mg, once every 4–6 hours.
  • Preventing gastric acid aspiration while under general anesthesia : 400 mg, given 90–120 minutes before administration of anaesthesia. In caesarean section patients, the dose is 400 mg given when labor begins. Dosage may be increased to 400 mg every 4 hours if necessary. The maximum dose is 2,400 mg per day.

The dose of cimetidine for pediatric patients will be adjusted by the doctor according to the patient's age and weight.

How to Take Cimetidine Correctly

Follow the doctor 's recommendations and read the information listed on the cimetidine packaging before starting to consume it. Do not increase your dose or use this drug for more than the time recommended by your doctor.

Cimetidine can be taken at mealtime, before bedtime, or as directed by your doctor. Swallow cimetidine tablets or capsules with water.

Take cimetidine at the same time every day for effective treatment. If you forget to take cimetidine, consume it immediately if it is not close to the schedule for taking the next drug. If it is close, ignore the missed dose and do not double the dose the next time you take the drug.

Continue treatment according to the time recommended by the doctor, even though the symptoms have improved. Stopping medication too early can hinder the healing process.

If your symptoms have not improved after 2 weeks of taking cimetidine, talk to your doctor about your condition.

Store cimetidine tablets or capsules in a closed container, in a cool place and away from sunlight. Keep medicine out of reach of children.

Cimetidine Interactions with Other Drugs

Interactions that can occur if cimetidine is used with certain drugs are:

  • Increased risk of developing potentially fatal arrhythmias (QT prolongation on EKG ) when used with dofetilide or pimozide
  • Increased risk of bleeding if taken with oral anticoagulants, such as warfarin
  • Increased levels and risk of side effects of amitriptyline, lidocaine , nifedipine, diltiazem , glipizide , phenytoin, procainamide, metformin , ciclosporin, tacrolimus, or theophylline
  • Increased absorption and risk of side effects of atazanavir
  • Increased decrease in blood cell production when used with chemotherapy drugs, such as fluorouracil or epirubicin
  • Decreased effectiveness of itraconazole or ketoconazole obat
  • Decreased absorption and effectiveness of cimetidine when used concomitantly or for less than 2 hours with sucralfate

Cimetidine Side Effects and Dangers

Some side effects that may arise after taking cimetidine include:

  • Muscle ache
  • Dizzy
  • Headache
  • Diarrhea
  • Drowsiness
  • Tired

Consult a doctor if the side effects above do not subside or get worse. Immediately see a doctor if you experience a drug allergic reaction or serious side effects that rarely occur, such as:

  • Depression
  • Anxiety or restlessness
  • daze
  • hallucination
  • Difficult to urinate
  • Gynecomastia (enlargement of breasts in males)
  • Decreased sexual desire
  • Easy bruising or bleeding
  • Signs of infection, such as fever, sore throat, and cough
  • The heart beats too fast, too slowly, or irregularly ( arrhythmia )
  • Decreased frequency of urination and amount of urine
  • Yellowish discoloration of the skin and eyes ( jaundice )
  • Difficulty or pain when swallowing
  • Vomiting blood, vomiting with dregs like coffee grounds, bloody bowel movements, or black stools like tar
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