Medical Specialty >> Pharmacy

Doctors Lounge - Pharmacy Answers

Back to Pharmacy Answers List

If you think you may have a medical emergency, call your doctor or 911 immediately. Doctors Lounge ( does not recommend or endorse any specific tests, physicians, products, procedures, opinions, or other information that may be mentioned on the Site.

DISCLAIMER: The information provided on is designed to support, not replace, the relationship that exists between a patient/site visitor and his/her physician. Please read our 'Terms and Conditions of Use' carefully before using this site.

Date of last update: 9/5/2017.

Forum Name: Pharmacy & Drug Topics

Question: How often can you take 2000mg of Flagyl?

 Cruise - Fri Aug 06, 2010 12:59 am

I was prescribed 2000mg of Flagyl on 6/15 for a probable bv infection or tv... I took the pills as I was supposed to and my symptoms went away. A few days ago my symptoms returned and I asked my doctor for a script. She gave me Flagyl 500 mg Bid for 7 days. I am going on a cruise and would not like to be on the antibiotics when I go. Is it safe to just take the 2000mg again since that cleared it up before?
 Dr.M.Aroon kamath - Sun Aug 15, 2010 10:39 pm

User avatar Hi,
You have not mentioned what the indication for the therapy. However,
the 2G single dose regimen is commonly prescribed for
- bacterial Vaginosis(BV),
- trichomonal Vaginosis, and
- Gardnerella vaginalis vaginitis.

In some studies, a single, 2-g dose of metronidazole given orally for the treatment of bacterial vaginosis resulted in a clinical cure rate of 65% and a therapeutic cure rate of 25% at 3 months.

Amsel criteria for BV is frequently used for assessing response to therapy.
Therapeutic cure: is defined as resolution of all 4 Amsel criteria and investigator cure and Nugent score: 0-3 for normal bacterial morphotypes.
Multivariate analyses in some studies have revealed that statistically significant variables associated with clinical failure were,
- African American race,
- smoking, and
- colonization with Mycoplasma hominis.

The use of condoms and oral contraceptives had some protective effect against clinical failure, but they did not reach statistical significance.
(Doug Brunk, OB/GYN News, September 15, 2004).

The data about long-term outcomes in women with bacterial vaginosis treated with single-dose metronidazole are very limited. There are no long-term studies, and most of the published treatment trials had involved small numbers of women.

In one study, a single 2-g dose of metronidazole was compared with a seven-day course of 500 mg given twice daily in the treatment of symptomatic Gardnerella vaginalis infection. Results showed only 46% (16/34) of patients treated with the single 2-g dose were considered cured compared with 86% of those treated with the seven-day course.
(JAMA. 1985; 254(8):1046-1049)

Bacterial Vaginosis: Routine treatment of male sexual partners is not necessary.
Trichomoniasis: sexual contacts should be treated regardless of symptoms.

Before repeat courses of therapy are given, the manufacturers recommend that the presence of the organism should be reconfirmed by wet smear and/or culture and an interval of 4–6 weeks should be allowed between courses of metronidazole.

If treatment failure occurs following an initial metronidazole regimen of a single 2-g dose and reinfection has been excluded, the CDC recommends that the patient be retreated with an oral metronidazole regimen of 500 mg twice daily for 7 days or, alternatively, a single 2-g dose of oral tinidazole. If retreatment fails, then 2 g of metronidazole or tinidazole should be given once daily for 5 days. If the multiple-dose regimen is also ineffective, consultation with a specialist is recommended and in vitro susceptibility testing of T. vaginalis isolates may be indicated.

Metronidazole vaginal gel or clindamycin vaginal cream placed inside the vagina can be used as alternatives to the oral regimens of metronidazole and have been shown to be equally effective.

I hope this information is helpful.
Best wishes!

| Check a doctor's response to similar questions

Are you a Doctor, Pharmacist, PA or a Nurse?

Join the Doctors Lounge online medical community

  • Editorial activities: Publish, peer review, edit online articles.

  • Ask a Doctor Teams: Respond to patient questions and discuss challenging presentations with other members.

Doctors Lounge Membership Application

Tools & Services: Follow DoctorsLounge on Twitter Follow us on Twitter | RSS News | Newsletter | Contact us