Penlac (Ciclopirox) - Topical

What Is Penlac?

Penlac (ciclopirox) is a prescription-only nail lacquer, which comes as a topical liquid solution that you apply directly to your nails. A topical medication is applied directly to a particular place on the body. Penlac is used to treat fungal nail infections, also called onychomycosis. 

Ciclopirox is an antifungal drug. Specifically, it belongs to a drug class called hydroxypyridone antimycotics. Penlac works by penetrating deep into the layers of the nail bed and surrounding skin. It kills fungus by blocking fungus from getting the nutrients it needs to grow.

Drug Facts

Generic Name: Ciclopirox
Brand Name: Penlac
Drug Availability: Prescription
Administration Route: Topical
Therapeutic Classification: Hydroxypyridone antimycotic
Available Generically: Yes
Controlled Substance: No
Active Ingredient: Ciclopirox
Dosage Form(s): Laquer, cream, shampoo

What Is Penlac Used For? 

Penlac treats mild to moderate fungal nail infections, also called onychomycosis, caused by the fungus Trichophyton rubrum. This fungus is the most common cause of fungal nail infections. 

Fungal nail infections are common in toenails but can also occur in fingernails. Fingernails or toenails with a fungal infection often appear discolored (usually yellow, brown, or white), thick, or cracked.

Anyone can get a fungal nail infection, but the following populations may be more likely than others to get a fungal nail infection:

  • People with diabetes or poor circulation
  • People with a weakened immune system (such as HIV or other immune system problems)
  • People who often get athlete’s foot (a fungal skin infection of the toes/foot)

How to Use Penlac

Penlac Nail Lacquer is applied to the infected nail once a day, preferably at bedtime, according to the steps below:

  1. If the infected nail has any loose areas, use a nail file or clippers to remove the loose nail material before applying Penlac.
  2. Use the included applicator brush to apply Penlac in an even layer over the infected nail. Be sure to coat your nail bed and the underside of the nail. Avoid getting Penlac on your skin, except for the skin that borders the infected nail.
  3. After applying the solution, give it a minute to dry before covering the nails with socks or gloves. Make sure to wait eight hours before taking a shower or bath.

The next day, apply another layer of ciclopirox over the previous coat. After a week of daily treatment, remove the nail lacquer with rubbing alcohol. Then return to the first step.

If you cannot trim your nail, you will likely need to have a caregiver or healthcare provider trim the infected nails once a month or as directed while using Penlac. Talk to your healthcare provider before trimming your nails if you have diabetes or problems with numbness in your hands or feet.

Here are a few additional tips to keep in mind when using Penlac:

  • Be careful not to get Penlac in your eyes, mouth, or genital area.
  • Do not use nail polish or other nail cosmetics.
  • Avoid using ciclopirox nail solution near an open flame because it is flammable. If you smoke, wait until the product is completely dry.


Penlac Nail Lacquer comes in a glass bottle with a screw-on cap with an attached applicator brush. Store the bottle in its original carton (to protect it from light) at room temperature between 59 and 86 degrees Fahrenheit (15 and 30 degrees Celsius). The product is flammable, so keep it from heat or open flame. Do not store it in the bathroom.

Close the bottle tightly after each use to prevent the solution from drying. It is also essential to prevent the solution from getting into the bottle threads, or else the cap may get stuck.

How Long Does Penlac Take to Work?

It takes a long time to treat fungal infections of the nails. However, most people notice an improvement within six months of daily Penlac use.

Fungal nail infections can be stubborn. As a result, Penlac may not completely clear the infection. Among people who used Penlac in a 48-week clinical trial for toenail fungal infections, less than 12% of people achieved clear or nearly clear results.

What Are the Side Effects of Penlac?

This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or healthcare provider. You may report side effects to the Food and Drug Administration (FDA) at or 800-FDA-1088.

Common Side Effects

Common side effects of using Penlac include:

  • Temporary skin irritation: Mild redness or burning sensation may occur where the solution comes in contact with your skin. Do your best to avoid getting Penlac Nail Lacquer on your skin, except for skin that borders your infected nail.
  • Nail discoloration
  • Change in nail shape
  • Ingrown toenail 

Severe Side Effects

Penlac should not cause serious side effects, but severe skin reactions in application areas have been reported. Tell your healthcare provider if you notice severe symptoms such as:

  • Severe irritation of the nail area: Oozing, blistering, burning, itching, or reddening
  • Allergic reaction: Rash

Long-Term Side Effects

Penlac is not known to cause long-term side effects. 

Report Side Effects

Penlac may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Penlac Should I Use?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For topical cream and lotion dosage forms:
    • Fungus infections (treatment):
      • Adults and children 10 years of age and over—Apply two times a day, morning and evening.
      • Children up to 10 years of age—Use and dose must be determined by your doctor.
    For topical gel dosage form:
    • Fungus infections (treatment) or seborrheic dermatitis (treatment):
      • Adults and children 16 years of age and over—Apply two times a day, morning and evening.
      • Children up to 16 years of age—Use and dose must be determined by your doctor.
    For shampoo dosage form:
    • Seborrheic dermatitis (treatment):
      • Adults and children 16 years of age and over—Apply 1 teaspoon (or up to 2 teaspoons for long hair) two times a week for four weeks with at least three days between each application.
      • Children up to 16 years of age—Use and dose must be determined by your doctor.
    For topical solution dosage form:
    • Fungus infections (treatment):
      • Adults —Apply once daily, preferably at bedtime or eight hours before washing.
      • Children up to 18 years of age—Use and dose must be determined by your doctor.


The following modifications (changes) should be kept in mind when using Penlac:

Severe allergic reaction: Avoid using Penlac if you have a known allergy to it or its ingredients. Ask your pharmacist or healthcare provider for a complete list of the ingredients if you're unsure.

Missed Dose

If you miss an application of Penlac, continue using it the next day at your usual time. Do not apply extra to make up for a missed dose.

Penlac treats a fungal nail infection best when you use it consistently. Try setting an alarm or reminder on your phone to help you remember to use it daily.

Overdose: What Happens If I Take Too Much Penlac?

There is limited information available about a Penlac overdose.

If you think you're experiencing an overdose or life-threatening symptoms, seek immediate medical attention.

What Happens If I Overdose on Penlac?

If you think you or someone else may have overdosed on Penlac, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Penlac, call 911 immediately.


Drug Content Provided and Reviewed by IBM Micromedex®

If your skin problem does not improve within 2 to 4 weeks, or if it becomes worse, check with your doctor.

Inform your doctor right away if the area where you applied the medicine shows signs of increased irritation (e.g., redness, itching, burning, blistering, swelling, or oozing) because it could be an allergic reaction.

Nail problems treated with the topical solution form of this medicine may take up to 6 months to start improving.

To help clear up your infection completely and to help make sure it does not return, good health habits are also required. The following measures will help reduce chafing and irritation and will also help keep the area cool and dry.

  • For patients using ciclopirox for ringworm of the groin (tinea cruris):
    • Avoid wearing underwear that is tight-fitting or made from synthetic materials (for example, rayon or nylon). Instead, wear loose-fitting, cotton underwear.
    • Use a bland, absorbent powder (for example, talcum powder) or an antifungal powder (for example, tolnaftate) on the skin. It is best to use the powder between applications of ciclopirox.
  • For patients using ciclopirox for ringworm of the foot (tinea pedis):
    • Carefully dry the feet, especially between the toes, after bathing.
    • Avoid wearing socks made from wool or synthetic materials (for example, rayon or nylon). Instead, wear clean, cotton socks and change them daily or more often if the feet sweat freely.
    • Wear sandals or well-ventilated shoes (for example, shoes with holes on top or on the side).
    • Use a bland, absorbent powder (for example, talcum powder) or an antifungal powder (for example, tolnaftate) between the toes, on the feet, and in socks and shoes freely once or twice a day. It is best to use the powder between applications of ciclopirox.

If you have any questions about these measures, check with your health care professional.

What Are Reasons I Shouldn’t Use Penlac?

You should not use Penlac if you have had an allergic reaction to ciclopirox or any of its ingredients.

What Other Medications Interact With Penlac?

Drug interactions occur when one drug affects how another drug works. No specific medicines are known to interact with Penlac.

Penlac Nail Lacquer is a topical solution. It is applied directly to the infected nail—the drug works within the layers of the nail bed and surrounding skin, killing fungus. Very little of the drug absorbs into your bloodstream. Therefore, it is unlikely to interfere with other medications.  

Before using Penlac, it is still a good idea to tell your healthcare provider about your current medications, including prescription drugs, over-the-counter (OTC) medicines, vitamins, herbs, and other dietary supplements. Sharing this information can help to prevent potentially harmful drug interactions.

What Medications Are Similar?

Penlac contains the active ingredient ciclopirox. It is a unique antifungal drug that you apply to the infected nail. Other antifungal medicines may be prescribed to treat fungal infections, but they do not work precisely the same way as ciclopirox.

Some examples of other antifungal drugs are:

  • Lamisil (terbinafine) - oral: Oral terbinafine (prescription-only) can be effective but may take several months to work. Some potential downsides include getting blood work and side effects such as headache, upset stomach, and liver problems.
  • OTC antifungals - topical: Some examples include Fungi-Nail and Kerasal. They may take several months to work and may not work for everyone.
  • Jublia (efinaconazole) - topical: Jublia is a prescription-only topical antifungal. It is similar to Penlac in that you paint it directly on the infected toenail, which may take up to 48 weeks to work.

Ask your pharmacist or a healthcare provider if you have questions about alternatives to Penlac.

Frequently Asked Questions

  • What is Penlac used for?

    Penlac is prescribed to treat nail fungal infections in which nails become discolored (usually yellow or white), thick, and prone to breakage. Penlac is applied directly to the infected nail once daily. 

  • Does Penlac have a generic version?

    Yes, a generic version of the drug is available: ciclopirox 8% topical solution. Generic medicines tend to cost less than brand-name medications.

  • Can I paint my nails after using Penlac?

    You should not apply nail polish or other nail cosmetics, such as artificial nails, to the infected nail during your treatment with Penlac. Using nail polish or fake nails will prevent the medication from penetrating deep into the layers of your nail, where it works to kill the infection-causing fungus.

  • How well does Penlac work?

    Most people notice improvement while using Penlac. But your nail may not look clearer until you have used this treatment consistently for several months.

    Fungal nail infections can take a long time to treat, and it is possible that Penlac may not completely clear the infection. Less than 12% of people who used Penlac in a clinical trial achieved clear or nearly clear results after about 11 months (48 weeks) of treatment.

How Can I Stay Healthy While Taking Penlac?

Fungal infections can discolor your nails and may make some people feel self-conscious. The good news is that several treatment options are available, including Penlac Nail Lacquer. Keep in mind that nail fungal infections, while common, can be stubborn, and it often takes several months of treatment to see improvement. Not everyone achieves completely clear nails even after 48 weeks (about 11 months) of treatment with Penlac.

If you are not seeing improvement within six months, consider talking to your healthcare provider about other treatment options.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Penlac nail lacquer (ciclopirox) topical solution, 8%.

  2. Centers for Disease Control and Prevention. Fungal nail infections.

  3. Food and Drug Administration. Jublia (efinaconazole) topical solution.

By Patricia Weiser, PharmD
Patricia Weiser, PharmD, is a licensed pharmacist and freelance medical writer. She has more than 14 years of professional experience.