Famotidine is a type of medicine called an H2 receptor antagonist. It acts in the stomach to decrease the production of stomach acid.
What is it used for?
- Treating and preventing recurrence of peptic ulcers.
- Gastro-oesophageal reflux disease.
- Excessive secretion of stomach acid due to a tumour or enlargement of the pancreas (Zollinger-Ellison syndrome).
How does it work?
- Famotidine is a type of medicine called an H2 receptor antagonist. It acts in the stomach to decrease the production of stomach acid.
- Famotidine works by blocking histamine H2 receptors that are found on the cells in the stomach lining. A natural body chemical called histamine normally binds to these receptors, causing the cells to produce stomach acid. By blocking the H2 receptors, famotidine prevents histamine from binding to them. This stops the cells from producing stomach acid.
- Stomach acid is produced in the stomach as a normal part of the digestive process.
How do I take it?
- Famotidine tablets can be taken either with or without food. They should be swallowed with a drink.
- The dose prescribed and how often the medicine needs to be taken depends on the condition being treated. Follow the instructions given by your doctor or pharmacist.
Use with caution in
- People with decreased kidney function.
Not to be used in
- People who are allergic to other H2 receptor antagonists, for example ranitidine, nizatidine.
- This medicine is not recommended for children, as its safety and effectiveness have not been studied in children.
- This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
- If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- The safety of this medicine for use during pregnancy has not been established. It is not recommended for use in pregnancy unless considered essential by your doctor. Seek further medical advice from your doctor.
- This medicine may pass into breast milk in small amounts. The amount is probably too small to have any harmful effects on a nursing infant. However, the manufacturer states that this medicine should only be used by women who are breastfeeding if considered essential by your doctor. Ask your doctor for advice before taking this medicine if you are breastfeeding.
Side effects
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
Common (affect between 1 in 10 and 1 in 100 people)
- Headache.
- Dizziness.
- Constipation.
- Diarrhoea.
Uncommon (affect between 1 in 100 and 1 in 1000 people)
- Nausea and vomiting.
- Abdominal discomfort or bloating.
- Wind (flatulence).
- Dry mouth.
- Loss of appetite.
- Taste disturbance.
- Skin reactions such as rash and itch.
- Fatigue.
Very rare (affect less than 1 in 10,000 people)
- Seizures.
- Pins and needles sensations.
- Sleepiness.
- Alteration in results of liver function tests.
- Yellowing of the skin or whites of the eyes (jaundice). Tell your doctor if you experience this.
- Inflammation of the liver (hepatitis).
- Hair loss.
- Muscle cramps.
- Joint pain.
- Allergic reactions.
- Anxiety and agitation.
- Confusion.
- Depression.
- Decrease in the normal numbers of red blood cells, white blood cells or platelets in the blood.
- Impotence (erectile dysfunction).
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.
For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to make sure that the combination is safe.
As famotidine lowers the acidity in the gut it may reduce the absorption of the following medicines, which could make them less effective:
- atazanavir
- cefpodoxime
- dasatinib
- erlotinib
- itraconazole
- ketoconazole
- lapatinib
- posaconazole
- raltegravir
- ulipristal.
Ask your pharmacist for advice if you are taking any of these.
This medicine should not be taken by people who are having histamine treatment for leukaemia, because this medicine may theoretically make the histamine less effective.
References:
http://www.netdoctor.co.uk/medicines/digestive-health/a7327/famotidine/
https://www.drugs.com/pepcid.html
https://www.pepcid.com
http://www.rxlist.com/pepcid-drug.htm
https://en.wikipedia.org/wiki/Famotidine
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