Metronidazole (Flagyl)

What is it?

Flagyl is an antibiotic used to treat infections caused by anaerobic bacteria, (i.e. bacteria not requiring oxygen to survive), particularly in the bowel.

What is it used for?

It has been shown to be effective in the treatment of anal complications of Crohn's disease, such as infected fistulae and fissures. It has also been shown to be as effective as Sulphasalazine in reducing mild to moderate inflammation in Crohn's disease.

How do I take it?

It can be taken as a:

Tablet an initial 'loading dose' is given, then 1 tablet 3 times daily
Injection it can be given by intravenous infusion followed by tablets
Suppository it can be given via the rectum

Are there any special precautions?

Flagyl interacts with certain drugs such as:

• oral anticoagulants (drugs that thin the blood)
• Phenobarbitone (an anti-epileptic drug)
• Lithium (an antidepressant drug)

Therefore careful monitoring during treatment may be required.

You should not drink alcohol when taking flagyl as they interact in the liver and can make you feel very ill.

Studies have shown that the drug has no adverse effect in pregnancy on the developing foetus and the small amounts found in breast milk are far less than the normal paediatric dose and is unlikely to cause harm.

Are there any side effects?

Most people are able to take flagyl without major problems, but some of the following side effects may occur:

• Nausea and vomiting
• Diarrhoea
• Abdominal pain
• Furred tongue and unpleasant taste in the mouth
• Reduced white cells in the blood
• Peripheral neuropathy (numbness and tingling in the fingers and toes) has been reported in long-term treatment

Side effects are usually reversible on stopping the drug, although peripheral neuropathy can occasionally persist.