What is Metrogel (metronidazole), and what is it used for?

Metrogel, Metrocream, and Metrogel Vaginal (metronidazole topical) is an antibiotic effective against anaerobic bacteria and certain parasites. Metrogel and Metrocream topical gel, cream, and lotion are used for treating rosacea. Metrogel Vaginal is used to treat bacterial vaginosis. It is not effective in treating Candidal vaginosis (“yeast infection“). Common side effects of Metrogel include

Other important side effects of Metrogel include bloating, dark urine, depression, and skin rash.

Drug interactions of Metrogel include alcohol and warfarin.

There are no adequate studies of Metrogel use in pregnant women. Orally administered metronidazole is secreted in human milk in concentrations similar to concentrations in the mother’s blood. Although metronidazole concentration in blood after vaginal or topical administration is small, potential effects on the infant should be considered.

What are the important side effects of Metrogel (metronidazole topical)?

Common side effects are:

Other important side effects include:

Disulfiram reactions when used with alcohol. Disulfiram reaction is associated with signs and symptoms of severe flushing that may be accompanied by tachycardia and low blood pressure (hypotension).

Metrogel (metronidazole) side effects list for healthcare professionals

Clinical Studies Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

In a controlled clinical trial, 557 patients used metronidazole gel, 1% and 189 patients used the gel vehicle once daily for up to 10 weeks. The following table summarizes selected adverse reactions that occurred at a rate of ≥ 1%:

Table 1: Adverse Reactions That Occurred at a Rate of ≥ 1%
System Organ Class/Preferred Term Metronidazole Gel, 1%
N= 557
Gel Vehicle
N= 189
Patients with at least one AE
Number (%) of Patients
186 (33.4) 51 (27.0)
Infections and infestations 76 (13.6) 28 (14.8)
Bronchitis 6 (1.1) 3 (1.6)
Influenza 8 (1.4) 1 (0.5)
Nasopharyngitis 17 (3.1) 8 (4.2)
Sinusitis 8 (1.4) 3 (1.6)
Upper respiratory tract infection 14 (2.5) 4 (2.1)
Urinary tract infection 6 (1.1) 1 (0.5)
Vaginal mycosis 1 (0.2) 2 (1.1)
Musculoskeletal and connective tissue disorders 19 (3.4) 5 (2.6)
Back pain 3 (0.5) 2 (1.1)
Neoplasms 4 (0.7) 2 (1.1)
Basal cell carcinoma 1 (0.2) 2 (1.1)
Nervous system disorders 18 (3.2) 3 (1.6)
Headache 12 (2.2) 1 (0.5)
Respiratory, thoracic and mediastinal disorders 22 (3.9) 5 (2.6)
Nasal congestion 6 (1.1) 3 (1.6)
Skin and subcutaneous tissue disorders 36 (6.5) 12 (6.3)
Contact dermatitis 7 (1.3) 1 (0.5)
Dry skin 6 (1.1) 3 (1.6)
Vascular disorders 8 (1.4) 1 (0.5)
Hypertension 6 (1.1) 1 (0.5)
Table 2: Local Cutaneous Signs and Symptoms of Irritation That Were Worse Than Baseline
Sign/Symptom Metronidazole Gel, 1%
N= 544
Gel Vehicle
N= 184
Dryness 138 (25.4) 63 (34.2)
Mild 93 (17.1) 41 (22.3)
Moderate 42 (7.7) 20 (10.9)
Severe 3 (0.6) 2 (1.1)
Scaling 134 (24.6) 60 (32.6)
Mild 88 (16.2) 32 (17.4)
Moderate 43 (7.9) 27 (14.7)
Severe 3 (0.6) 1 (0.5)
Pruritus 86 (15.8) 35 (19.0)
Mild 53 (9.7) 21 (11.4)
Moderate 27 (5.0) 13 (7.1)
Severe 6 (1.1) 1 (0.5)
Stinging/burning 56 (10.3) 28 (15.2)
Mild 39 (7.2) 18 (9.8)
Moderate 7 (1.3) 9 (4.9)
Severe 10 (1.8) 1 (0.5)

The following additional adverse experiences have been reported with the topical use of metronidazole: skin irritation, transient redness, metallic taste, tingling or numbness of extremities, and nausea.

Post Marketing Experience

The following adverse reaction has been identified during post approval use of topical metronidazole: peripheral neuropathy. Because this reaction is reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate the frequency or establish a causal relationship to drug exposure.

What drugs interact with Metrogel (metronidazole)?

Oral metronidazole has been reported to potentiate the anticoagulant effect of coumarin and warfarin, resulting in a prolongation of prothrombin time. Drug interactions should be kept in mind when Metrogel (metronidazole) is prescribed for patients who are receiving anticoagulant treatment, although they are less likely to occur with topical metronidazole administration because of low absorption.

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Medically Reviewed on 10/21/2019

References

FDA Prescribing Information

Professional side effects and drug interactions sections courtesy of the U.S. Food and Drug Administration.