Trichomoniasis is a disease caused by a parasite called Trichomonas vaginalis that can live in semen or vaginal fluids. It spreads during unprotected anal, oral, or vaginal sex, usually between a man and a woman or between two women. Keep in mind that a man doesn’t have to ejaculate to give his partner the parasite.
The prevalence of Trichomonas vaginalis in the United States is 2.1% among women ages 14-59, and 0.5% among men based on a nationally representative sample of people who participated in NHANES survey. The following are other findings from this study according to the CDC:
- Prevalence was 9.6% for African American women, 1.4% for Hispanic women, and 0.8% for non-Hispanic white women.
- For men and women, increasing poverty level, lower educational level, unmarried status, and having been born in the U.S. are associated with T. vaginalis infection.
- For women, younger age at first sex, greater number of sex partners, and a history of chlamydia infection in the past 12 months are associated with T. vaginalis infection.
What is Metronidazole?
Metronidazole is an antibiotic and antiprotozoal medication marketed under the brand name Flagyl among others. It is used either alone or with other antibiotics to treat pelvic inflammatory disease, endocarditis, and bacterial vaginosis. It is effective for dracunculiasis, giardiasis, trichomoniasis, and amebiasis.
Metronidazole tablets, liquid and suppositories are prescribed for a number of infections including the ones listed above. The form your doctor prescribes, the dose and how long you’ll need to take the medicine for depends on the type of infection and how serious it is.
Some infections can be treated with a single dose, while others may need a 2 week course. Follow the instructions from your doctor or pharmacist.
Metronidazole tablets should be swallowed whole with a drink of water, after you’ve eaten some food. Metronidazole liquid does not need to be taken after food. This medicine comes with a plastic syringe or spoon to help you measure out the right dose. If you do not have one, ask your pharmacist for one. Do not use a kitchen teaspoon as it will not give the right amount.
Your doctor may prescribe metronidazole suppositories if you have difficulty swallowing medicines. Metronidazole suppositories are usually used 3 times a day. Follow the instructions that come in the packaging with your medicine.
If you need to take several doses of metronidazole a day, try to space them evenly. For example, if you take your medicine 3 times a day, this could be first thing in the morning, mid-afternoon, and at bedtime.
How long should I take it for?
It’s very important to keep taking metronidazole for as long as your doctor has prescribed it. It works by stopping the growth of the bacteria (or parasites) causing the infection. For most infections, you should feel better within a few days.
How long does metronidazole take to cure trichomoniasis?
The fastest way to cure trichomoniasis, even for pregnant women, is to swallow one megadose of either metronidazole or tinidazole. In some cases, your doctor might recommend a lower dose of metronidazole two times a day for seven days. Both you and your partner need treatment. Trichomoniasis is unlikely to go away without treatment. The infection may cure itself in rare cases, but you risk passing the infection on to someone else even if you got the infection on your own when you’re not treated.
What are the side effects of metronidazole?
Get emergency medical help if you have signs of an allergic reaction to metronidazole (hives, itching, warmth or tingling; fever, joint pain; dry mouth, dry vagina; stuffy nose, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).
Call your doctor at once if you have:
- new or worsening symptoms of infection;
- painful or difficult urination;
- a light-headed feeling (like you might pass out); or
- blisters or ulcers in your mouth, red or swollen gums, trouble swallowing.
Stop taking the medicine and call your doctor right away if you have neurologic side effects (more likely to occur while taking metronidazole long term):
- numbness, tingling, or burning pain in your hands or feet;
- vision problems, pain behind your eyes, seeing flashes of light;
- muscle weakness, problems with speech or coordination;
- trouble speaking or understanding what is said to you;
- a seizure; or
- fever, neck stiffness, and increased sensitivity to light.
Metronidazole can cause life-threatening liver problems in people with Cockayne syndrome. If you have this condition, stop taking this medicine and contact your doctor if you have signs of liver failure–nausea, stomach pain (upper right side), dark urine, clay-colored stools, or jaundice (yellowing of the skin or eyes).
Side effects may be more likely in older adults.
Common metronidazole side effects may include:
- depression, trouble sleeping, feeling irritable;
- headache, dizziness, weakness;
- nausea, vomiting, loss of appetite, stomach pain;
- diarrhea, constipation;
- unpleasant metallic taste;
- rash, itching;
- vaginal itching or discharge, pain during sex;
- mouth sores; or
- swollen, red, or “hairy” tongue.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. Read: Does Flagyl Cause Early Period