Metronidazole (me-troe-NIH-duh-zole) is used to treat parasitic infections of the small intestine, amebic liver abscess and amebic dysentery, bacterial vaginosis, trichomonas vaginal infections, and carriers of trichomonas (both sexual partners) who do not have symptoms of infection. Metronidazole is used alone or in combination with other antibiotics in treating abscesses in the liver, pelvis, abdomen and brain caused by susceptible anaerobic bacteria. This medication is also used in treating infection of the colon and in combination with other drugs to treat Helicobacter pylori (H. pylori) that causes stomach or intestinal ulcers.
Metronidazole may be taken orally with or without food. It is usually taken two or three times a day for 5-10 days or longer. Take Metronidazole exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor. Be sure to use Metronidazole for the full course of treatment. If you do not, the medicine may not clear up your infection completely. The bacteria could also become less sensitive to this or other medicines. This could make the infection harder to treat in the future.
Metronidazole is a valuable antibiotic and is generally well tolerated with appropriate use. Minor side effects include nausea, headaches, loss of appetite, a metallic taste, and rarely a rash. If you experience any of the following symptoms: severe allergic reactions (rash, hives, itching, difficulty breathing, stuffy nose, tightness in the chest, swelling of the mouth, face, lips, or tongue); bloody stools, increased or decreased urination, numbness, tingling, or burning of your arms, hands, legs, or feet; seizures, severe diarrhea, sore throat, chills, or fever; stomach pain or cramps; vaginal itching, odor, or discharge; white patches in the mouth, fever, joint pain, stomach pain, cramps, occur; call your doctor immediately. Do not treat diarrhea without first checking with your doctor. Serious side effects of Metronidazole are rare. Serious side effects include seizures and damage of nerves resulting in numbness and tingling of extremities (peripheral neuropathy). Metronidazole should be stopped if these symptoms appear.
Before taking Metronidazole, tell your doctor if you are allergic to Metronidazole or any other drugs.
Tell your doctor if you have or have ever had blood, kidney, or liver disease or Crohn's disease.
Plan to avoid unnecessary or prolonged exposure to sunlight and to wear protective clothing, sunglasses, and sunscreen. Metronidazole may make your skin sensitive to sunlight.
The liver is primarily responsible for eliminating Metronidazole from the body, and doses may need to be reduced in patients with liver disease and abnormal liver function.
Tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking Metronidazole, call your doctor.
Metronidazole is not used in early pregnancy (first 3 months) because of potential adverse effects on the fetus.
Metronidazole is excreted in breast milk. Nursing mothers, because of potential adverse effects on the newborn, should not use Metronidazole.
Long-term or repeated use of Metronidazole may cause a second infection. Tell your doctor if signs of a second infection occur. Your medicine may need to be changed to treat this.
Hormonal birth control (eg, birth control pills) may not work as well while you are using Metronidazole.
To prevent pregnancy, use an extra form of non-hormonal birth control (such as condoms).
Metronidazole may interfere with certain lab tests. Be sure your doctor and lab personnel know you are taking Metronidazole.
Lab tests, including liver function and white blood cell counts, may be performed while you use Metronidazole. These tests may be used to monitor your condition or check for side effects. Use Metronidazole with caution in the elderly; they may be more sensitive to its effects.
Tell your doctor what prescription and nonprescription medications you are taking, especially anticoagulants ('blood thinners') such as warfarin (Coumadin), astemizole (Hismanal), disulfiram (Antabuse), lithium (Lithobid), phenobarbital, phenytoin (Dilantin), and vitamins.
Alcohol should be avoided because Metronidazole and alcohol together can cause severe nausea, vomiting, cramps, flushing, and headache.
Metronidazole can increase the blood thinning effects of warfarin (Coumadin) and increase the risk of bleeding probably by reducing the break down of warfarin.
Cimetidine (Tagamet) increases blood levels of Metronidazole while cholestyramine reduces blood levels of Metronidazole by reducing its absorption.
Metronidazole should not be combined with Amprenavir for treating human immunodeficiency disease (infection with HIV) because Amprenavir contains propylene glycol. Metronidazole blocks the breakdown of propylene glycol in the liver leading to accumulation of propylene glycol in blood. Accumulation of propylene glycol could cause seizures, increased heart rate, and lead to kidney failure.
Metronidazole increases the blood levels of Carbamazepine, Lithium and Cyclosporine though unknown mechanisms. Serious reactions may occur if these drugs are taken with Metronidazole.
If you miss a dose of Metronidazole, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.
Store below 77° F (25° C) and protect from light.