Cimetidine

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Cimetidine belongs to the group of medicines known as histamine H2-receptor antagonists which act to decrease the natural production of acid in the stomach. Histamine is a natural chemical that stimulates stomach cells into producing acid. Histamine H2-antagonists decrease the production of acid-producing cells and pepsin, an enzyme that helps in the digestion of protien. thus allowing for the healing of the ulcers in the stomach and the duodenum.

Cimetidine is used to treat certain conditions which have been caused by too much acid being produced in the stomach, such as: stomach ulcers (gastric ulcers), ulcers of the upper part of the intestine (duodenal ulcers), reflux oesophagitis (acid reflux or heartburn) and Zollinger-Ellison disease.

Cimetidine is also used with caution when given to patients that take other drugs. This is because it affects the actions of certain enzymes in the liver, where many drugs are broken down. It would be prescribed with caution if anticoagulants and anticonvulsants are taken as there levels need to be carefully controlled.

Cimetidine can also be used to treat and prevent irritation and ulceration of the stomach caused by non-steroidal anti-inflammatory drugs (NSAIDs), such as diclofenac. Excess acid in the stomach caused by a tumor in the pancreas (Zollinger-Elison syndrome). It is also effective in treating stomach upsets such as indigestion, It can also be useful when given before general anaesthesia to prevent damage to the lungs caused by breathing in stomach fluids (acid aspiration).

Detailed Information

Quick Guide

• Anti-ulcer drug with overdose danger – LOW.
• Dependency is said to be – LOW.
• Prescription only drug – NO (to some preparations).
• Available as generic – YES.
• Alcohol Avoidance – YES.
• Alcohol may aggravate your condition and work against the beneficial effects of cimetidine. This may also be true of excessive amounts of coffee, fatty or spicy food.
• Tablet may be swallowed with a glass of water.
• Try to take cimetidine at the same times each day. This may help to avoid missing any doses.
• Avoid smoking if possible. It may help increase the amount of acid your stomach produces. Making your symptoms worse.

Side Effects

You may if prescribed cimetidine suffer one or more of these side effects, in the initial stages. However, you may find you do not suffer any at all. It does not follow that taking this medication will cause unwanted side effects.

Common: Diarrhoea, Dizziness, Confusion, Tiredness.
Rare: Muscle Pain, Breast enlargement in men, Rash, hallucinations, liver disorders.
Very Rare: Kidney disorders, inflammation of the pancreas, headache, heart effects (irregular, slow or fast heart beats), Impotence.

If you experience fever, sore throat, bruising or bleeding, speak with your doctor straight away.

The side effects listed here are the most common and rare problems reported by patients using this medication It may not include all of the side effects reported by the drug’s manufacturer. If common side effects persist you need to inform your doctor. Notify your doctor or pharmacist if you suffer any of the rare or some other side effects not listed here.

Prolonged Use

Long term use would not be an issue as courses would be unlikely to last longer than 8 weeks.

Driving, Hazardous Work & Alcohol

Because it is possible to suffer from dizziness and confusion when taking this medication you should refrain from these activites until you know how cimetidine affects you. The drinking of alcohol would also be an issue as it may cause aggravation to the under-lying condition, denying you the beneficial effects of cimetidine.

Pregnancy and Breast-Feeding

The safety of cimedine has not been established in pregnancy. Cimetidine may be excreted into the breast milk, but at normal doses it is unlikely to cause any problems to the baby. However, you should discuss both these important issues with your doctor or health care professional.

Cimetidine is classified as a Pregnancy Category B Medicine, by the US. Food and Drug Administration (FDA) Category B… Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women OR Animal studies have shown an adverse effect, but adequate and well-controlled studies in pregnant women have failed to demonstrate a risk to the foetus in any trimester.

Tell Your Doctor or Pharmacist

You should tell your doctor if you have a current health problem. For example: heart disease, kidney problems, if you are pregnant or you intend to become pregnant, or if you think you may be at risk from drug treatment for any other reason. Some types of medication can cause serious adverse effects when taken side by side so it is important to tell your doctor of any other medication you are already taking. This should also include any over-the-counter medication. For example: Painkillers, cold remedies, herbal and complimentary/alternative medication.

Over 60’s & Children

Before cimedine is prescribed to the elderly the risk of stomch cancer (higher risk) would need to be excluded. A reduced dose would need to be given when prescribed for children.

Overdose

If for what ever reason you take an unintentional extra dose it would be unlikey to give rise for concern. If a large overdose has been taken you should inform your doctor.

Other Medication Reactions

Cimetidine may increase the blood levels of anticonvulsant and increase the effects of anticoagulant medication, both may need an adjustment to there dosage. Some of the drugs from the benzodiazepine family may have there blood levels increased by cimetidine leading to an increase in adverse effects. Cimetidine may also increase the blood level of sildenafil. Theophylline/aminophylline may have blood levels increased if cimetidine is taken at the same time. Beta blockers or antiarrhythmic drugs, cimetidine may increase the blood levels of these drugs.

Missed A Dose

Do not take the missed dose, continue the regular dosing schedule. Do not take a double dose to make up for a missed one. Ideally you would have already checked with your doctor. If you have trouble remembering to take the tablets, tell your doctor or pharmacist.

Reducing or Stopping Medication

Symptoms could recur if you stop taking your medication. If prescribed by your doctor speak to him or her beforehand.

Effect Of Medication (from one dose)

The onset of effects could be felt within 90 minutes. The duration of action may be felt between 2 to 6 hours

Safety and Storage

• Never take more than the original dosage prescribed by your doctor.
• If your due to have treatment like an operation or dental work tell the person carrying out the treatment which medicines you are taking.
• When you buy any medicines over-the-counter check with the pharmacist that they are safe to take with your other medicines.
• Never take Cimetidine if it has past the expiry date shown on the box or container.
• Do not store Cimetidine above a temperature of 25°C or above a working area where high condensation may exist.
• Keep Cimetidine in its original container, in a cool dry place, away from the reach and eye sight of children.
• Always read the printed information leaflet that comes with your medicine if possible, before beginning treatment.
• Do not discard old or unwanted drugs into your trash, sink or toilet.
• Return all unused or old medicines/drugs to your pharmacist. who will dispose of them safely. without causing unwanted effects on our inviroment.

If Cimetidine has been prescribed for you never allow anyone else to use it, even if you know or others feel their symptom are similar to your own.

Do not leave your doctors surgery until you have a clear understanding of what the drug your doctor has prescribed for you does, and why you have been prescribed it. It is common for people who do not understand the reason behind there treatment to take their medication correctly.

Reference:

• Dexcel Pharma Ltd Patient Information Leaflet (PIL) last updated on electronic Medicines Compendium eMC: 18/08/2009. Cimetidine 200mg, 400mg, 800mg Tablets.
• Rosemont Pharmaceuticals Limited Patient Information Leaflet (PIL) last updated on electronic Medicines Compendium eMC: 24/03/2010. Cimetidine 200mg/5ml Oral Solution.
• British National Formulary – 61st Edition (March 2011) British Medical Association and Royal Pharmaceutical Society of Great Britain, London.