Metronidazole

Brand names

• Apo-Metronidazole
• Femazole
• Flagyl
• Flagystatin
• Lagyl
• Metizol
• MetroCream
• MetroGel
• Metro IV
• Metryl
• Neo-Tric
• Nidagel
• Novo-Nidazole
• PMS-Metronidazole
• Protostat
• Rho-Metrostatin
• Rosasol
• SK Metronidazole
• Trikacide

Usage

To treat numerous bacterial infections, including certain sexually transmitted diseases, gynecological infections, amebiasis (amoeba infection in the intestine or liver), brain abscess or meningitis, pneumonia or other lung infections, blood poisoning, bone and joint infections, infections of the internal organs (including liver abscess and peritonitis), and skin infections.

How it works

Metronidazole kills bacteria and protozoa, probably by disrupting the organism's synthesis of DNA.

Side effects

Serious

Oral and injection forms: Pain, tingling, numbness, or weakness in hands or feet; seizures.

Common

Oral and injection forms: Diarrhea, dizziness, lightheadedness, headache, loss of appetite, nausea, vomiting, stomach pains or cramps. Vaginal gel: Vaginal itching; painful intercourse; thick, white vaginal discharge; irritation of sexual partner's penis; burning urination; more frequent urination; redness, stinging, or itching of genital area.

Less common

Oral and injection forms: Change in taste, dry mouth, sharp metallic taste in mouth. Cream and gel: Dry skin, skin irritation, watery eyes with burning or stinging. Vaginal gel: Dizziness, lightheadedness, diarrhea, furry tongue, loss of appetite, metallic taste in the mouth, nausea, vomiting.

Possible interactions

Other medicaments:

Metronidazole may increase the effects of:

• carbamazepine (Tegretol) and lead to toxicity.
• warfarin (Coumadin, etc.) and cause abnormal bleeding; the INR (prothrombin time or protime) should be monitored closely, especially during the first 10 days of concurrent use.

Metronidazole taken concurrently with:



• antacids may decrease absorption of metronidazole.
• birth control pills (oral contraceptives) may block the effectiveness of contraception and result in pregnancy.
• cholestyramine (Questran) or other cholesterol-lowering resins may decrease metronidazole absorption and lower its therapeutic effect.
• cotrimoxazole or other sulfa medicaments may result in a disulfiramlike effect.
• cyclosporine (Sandimmune) can lead to cyclosporine toxicity.
• disulfiram (Antabuse) may cause severe emotional and behavioral disturbances.
• lithium (Lithobid, others) can cause lithium toxicity.
• phenytoin (Dilantin) or fosphenytoin (Cerebyx) may result in increased blood levels of phenytoin; more frequent blood level testing is needed, and the phenytoin dose should be adjusted to blood levels.
• ritonavir (Norvir) may increase blood levels of metronidazole.
• sirolimus (Rapamune) may increase risk of sirolimus toxicity.
• sulfamethoxazole (Septra, others) and perhaps other sulfa medicaments may lead to a disulfiramlike reaction.
• tacrolimus (Prograf) may increase risk of tacrolimus toxicity.
• trimethoprim (Septra, others) and perhaps other sulfa medicaments may lead to a disulfiramlike reaction.

Herbal medicines or minerals:

Some patients use Echinacea to attempt to boost their immune systems. Unfortunately, use of Echinacea is not recommended in people with damaged immune systems (even if a medicine caused the damage). This herb may also actually weaken any immune system if it is used too often or for too long a time. Do not take mistletoe herb, oak bark or marshmallow root and licorice.

Alcohol:

It is not advisable to drink alcohol while taking metronidazole.