Potential metronidazole gel side effects, according to the experts

Metronidazole is a prescription antibiotic that comes in intravenous, pill, gel, and cream forms. Each is used to treat different types of infections, and depending on the form, different side effects may occur. 

Here we’ll explain what metronidazole is, how it works, and potential metronidazole gel side effects (the form of metronidazole commonly used in skincare). We’ll also highlight the typical time it takes to clear up some of the conditions that metronidazole treats.

What is metronidazole? 

Metronidazole is an antimicrobial that treats different types of infections and conditions.¹ When it comes to skincare, it’s commonly used as a treatment for rosacea, partially due to its anti-inflammatory properties.² It’s a powerful antibiotic and should only be used as directed by a medical provider. It has many different uses and comes in several forms, including: 

• Immediate-release pills

• Slow-release pills

• Topical creams, gels, and lotions (like some of our Curology prescription formulas) 

• Vaginal gels 

• Injectable solutions

Metronidazole in skincare

In skin care, metronidazole is often prescribed as a topical medication to treat certain rosacea symptoms. No one knows exactly what causes rosacea (yet), but potential factors may include an overactive immune system, genetics, skin mites (Demodex), intestinal bacteria (helicobacter pylori),³ or a combination of these. Rosacea is not a bacterial infection, but research shows the anti-inflammatory and antibacterial effects of metronidazole can help reduce some of the symptoms frequently associated with rosacea—namely acne-like lesions (papules and pustules).⁴ Curology uses metronidazole in some of its prescription formulas for rosacea based on this research.

Metronidazole is also used to treat perioral dermatitis—an inflammatory skin condition that appears as a rash around the mouth. Small red or pink spots with an acne-like appearance are common symptoms. The exact cause of perioral dermatitis is unknown, but some triggers include steroid creams, cosmetics, and hormonal fluctuations.⁵

Potential metronidazole gel side effects

Side effects of metronidazole depend on its form—here we’ll focus on topical metronidazole gel side effects for rosacea. In general, follow your medical or dermatology provider’s indications and avoid the eye area. Here are some of the more common side effects:⁶

• Burning and stinging

• Itching

• Dryness 

• Scaline 

Rare but more serious side effects of topical metronidazole include but are not limited to:

• Headache 

• Metallic taste

• Contact dermatitis 

• Upper respiratory tract infection

Should you experience any of these, contact your healthcare provider. 

One concern that often comes up is metronidazole gel’s side effects on vaginal discharge.⁷ This is related to vaginal gel—a form of metronidazole that’s not used topically on the face. You may also experience other metronidazole gel side effects. Bleeding, however, is not one of those. If you experience any side effects for an extended period or your side effects worsen, contact your medical or dermatology provider. 

Although rare, some have reported adverse gastrointestinal reactions after using topical metronidazole and alcohol products. This is typically more common when metronidazole is taken orally.

How long does it take for metronidazole to work?

How long it takes for symptoms of rosacea or perioral dermatitis to clear when using metronidazole depends on which of the two conditions you’re treating. Again, it’s essential to follow and complete the treatment according to the prescribing provider’s instructions.

Metronidazole and rosacea

Acne-like lesions from rosacea can start to show improvement after about three weeks of starting treatment.  Metronidazole gel can help reduce symptoms of rosacea, such as the appearance of inflammatory lesions and erythema (redness) but has little effect on telangiectasia (visible blood vessels).⁸ 

Metronidazole and perioral dermatitis

Metronidazole cream or gel is often the first line of defense in treating perioral dermatitis, but it's often used along with other medications. You’ll likely be advised to discontinue using any facial products that may have caused the rash. Many people may notice an improvement after the first few weeks of using metronidazole gel; however, it can take up to 3 months to see its peak effects.⁹ Perioral dermatitis can be a chronic relapsing condition requiring long-term treatment, so the best thing you can do is explore your treatment options with your dermatology provider.  

Does Curology offer metronidazole?

Metronidazole is available by prescription only. If you have rosacea, your Curology provider may prescribe topical metronidazole in your personalized prescription formula.* Not signed up yet? Getting started is easy. Just answer a few questions and snap some selfies to help us get to know your skin.

If Curology is right for you, one of our licensed dermatology providers will work with you to examine your skin, assess your skincare goals, and provide custom treatment options. They’ll also be with you every step of the way to answer any questions. Our goal is to help take the guesswork out of your skincare routine.**

P.S. We did the homework so you don’t have to:

1. Weir, C.B. and Le, J.K. Metronidazole. StatPearls. (2022, June 30).

2. McClellan, K.J. and Noble, S. Topical metronidazole. A review of its use in rosacea.American Journal of Clinical Dermatology. (May-June 2000).

3. American Academy of Dermatology. Rosacea: Who gets and causes. (n.d.).

4. Thiboutot, D., et al. Standard management options for rosacea: The 2019 update by the National Rosacea Society Expert Committee. Journal of the American Academy of Dermatology. (2020).

5. Tolaymat, L. and Hall, M.R. Perioral dermatitis.StatPearls. (2022, May 27).

6. FDA.gov. Metrogel. (March 2010).

7. Sandoz Inc. METRONIDAZOLE-metronidazole gel. (October 2019).

8. McClellan, K.J. and Noble, S. Topical metronidazole. A review of its use in rosacea.American Journal of Clinical Dermatology. Ibid.

9. Tolaymat, L. and Hall, M.R. Perioral dermatitis.StatPearls. Ibid.

Donna McIntyre is a board-certified nurse practitioner at Curology. She obtained her Master of Science in Nursing at MGH Institute of Health Professions in Boston, MA.

* Ingredients determined by provider.

** Subject to consultation. Subscription is required. Trial is 30 days. Results may vary.

Written by

Curology Team

Medically reviewed by

Donna McIntyre, NP-BC