It is important that your doctor check your progress after you finish taking this medicine. This is to make sure that the infection is cleared up. Blood tests may be needed to check for unwanted effects.
If your symptoms do not improve within a few days after you start this medicine or if they become worse, check with your doctor.
Drinking alcoholic beverages while using this medicine may cause stomach pain, nausea, vomiting, headache, or flushing or redness of the face. Other alcohol-containing preparations (e.g., elixirs, cough syrups, tonics) may also cause problems. These problems may last for at least one day after you stop using metronidazole. This medicine may also cause alcoholic beverages to taste different. You should not drink alcoholic beverages or take other alcohol-containing preparations while you are using this medicine and for at least 3 days after stopping it.
Using this medicine while you are pregnant (especially during the first 3 months of pregnancy) can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using the medicine, tell your doctor right away.
If you are using this medicine for trichomoniasis (an infection of the sex organs in men or women), your doctor may want to treat your sexual partner at the same time you are being treated, even if he or she has no symptoms. Also, it may be desirable to use a condom (rubber) during sexual intercourse. These measures will help to keep you from getting the infection back again from your partner. If you have any questions about this, check with your doctor.
Check with your doctor right away if you are having burning, numbness, tingling, or painful sensations in the arms, hands, legs, or feet. These could be symptoms of a condition called peripheral neuropathy.
Check with your doctor right away if you have dizziness, problems with muscle control or coordination, shakiness or an unsteady walk, slurred speech, or trouble with speaking. These may be symptoms of a serious brain condition called encephalopathy.
Call your doctor right away if you have confusion, drowsiness, fever, a general feeling of illness, a headache, loss of appetite, nausea, a stiff neck or back, or vomiting. These could be symptoms of a serious condition called aseptic meningitis.
Metronidazole may cause dry mouth, an unpleasant or sharp metallic taste, and a change in taste sensation. For temporary relief of dry mouth, use sugarless candy or gum, melt bits of ice in your mouth, or use a saliva substitute. If your mouth continues to feel dry for more than 2 weeks, check with your medical doctor or dentist. Continuing dryness of the mouth may increase the chance of dental disease, including tooth decay, gum disease, and fungus infections.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.