Terbinafine is an antifungal that is available in over-the-counter (OTC) medicines that treat symptoms associated with skin fungus infections such as athlete’s foot, jock itch, and ringworm. Terbinafine can be found in single-ingredient topical skin fungus medicines.
Symptoms Treated
Symptoms Treated
More specifically:
Skin fungus, Athlete’s foot, Jock itch, Ringworm
Common Products
- Lamisil
- Store Brands (ex. Walmart’s “Equate” store brand or CVS Health store brand)
Dosing Information
Different types of products containing this active ingredient have different strengths. That’s why it is always important to read and follow the Drug Facts label. Most medicines warn against use of an active ingredient for longer than 7-10 days. Stop use and ask a doctor if symptoms persist.
A Note to Families:
1. Scientific and medical authorities around the world recognize acetaminophen as the only analgesic considered safe for use throughout an entire pregnancy when used according to the Drug Facts label.
2. There are no studies showing that acetaminophen use in children or during pregnancy causes autism.
3. Autism has many known risk factors, including genetics, but there is no clear, single cause.
4. Major health authorities like the FDA, CDC, and healthcare organizations such as the American College of Obstetricians and Gynecologists (ACOG) do not have warnings against acetaminophen use during pregnancy based on any known risk of autism and all recommend acetaminophen as the safest analgesic to use during pregnancy for short-term pain relief.
Frequently Asked Questions:
In fact, the Autism Science Foundation (ASF), a non-profit organization funding scientific autism research, specifically states that: it is disingenuous and misleading to boil autism's causes down to one simple thing," as there are hundreds of genes linked to autism in addition to other complex environmental factors.
Additionally, the most recent and rigorous research on this topic does not show a causal link to autism. The 2024 study published in the Journal of the American Medical Association (JAMA) analyzed nearly 2.5 million children using the gold-standard sibling comparison method, which controls for shared genetics and family environment, and found no association between acetaminophen use during pregnancy or infancy and neurodevelopmental issues such as autism.
- CDC Yellow Book (Current as of April 23, 2025): “Acetaminophen remains the non-opioid analgesic of choice during pregnancy.”
- FDA’s Acetaminophen Page (Current as of August 14, 2025): “To date, FDA has not found clear evidence that appropriate use of acetaminophen during pregnancy causes adverse pregnancy, birth, neurobehavioral, or developmental outcomes.”
Additionally, the Society for Maternal-Fetal Health, a professional organization for obstetricians with subspecialty training in maternal-fetal medicine, stated on September 25, 2025 that it: "...continues to advise physicians and patients that acetaminophen is an appropriate medication to treat pain and fever during pregnancy…the weight of scientific evidence that acetaminophen use during pregnancy causes an increased risk for autism or ADHD is simply inconclusive…”
Safety Guide
Safety Guide
Terbinafine is approved by the U.S. Food and Drug Administration (FDA) and is safe and effective when used according to the Drug Facts label. These products are for external use only.
Safe use tips:
- These products should not be used on the nails or scalp.
- These products should not be used to treat vaginal yeast infections.
- You should avoid getting the medicine near your mouth or into your eyes.
- You should wash the affected area and dry thoroughly before use.
- If you are treating athlete’s foot, pay special attention to the spaces between the toes; wear well-fitting, ventilated shoes; and change your socks and shoes at least once a day.
Ask a healthcare provider before use if:
- If you are pregnant, planning to become pregnant, or are breast-feeding.
- If you have allergies to medicines, foods, or other substances
- If you have a history of kidney or liver problems, lupus, depression, psoriasis, alcohol abuse or dependence, or blood problems (eg, anemia).
- If you have a weakened immune system or low white blood cell counts.
Do not use if:
- You are allergic to any ingredient in terbinafine tablets and hydroxypropyl-chitosan.
- You have liver problems.
Stop use and ask a doctor If:
- Too much irritation occurs or gets worse.
- There is no improvement of athlete’s foot, ringworm, or jock itch after one week of treatment.
- You accidentally swallow the medicine. Immediately contact a healthcare provider or the poison control national helpline at 800.222.1222.
What are the side effects of terbinafine?
- Change in or loss of taste or smell.
- Headache
- Increased sensitivity to sunlight; wear sunscreen.
- Although rare, call your doctor right away if you notice an allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, or trouble breathing.