Onychomycosis, more commonly known as nail fungus, is a very common condition that can cause your nails to thicken, discolor, and even change shape. While not usually painful, nail fungus can be unsightly and difficult to treat.
One treatment option your doctor may suggest is Lamisil, a prescription antifungal medication whose active ingredient is terbinafine hydrochloride. While there are other treatments out there, like Jublia, Lamisil is often prescribed because it can be very effective.
If your doctor has suggested Lamisil for your nail fungus, you probably have a lot of questions. What is the right dosage? What are the side effects? Are there any drug interactions to worry about? What are the warnings I should be aware of?
This article will answer all of those questions and more, giving you a comprehensive overview of Lamisil for fungus nail infections.
Understanding Lamisil: Description and Mechanism of Action
Lamisil comes in the form of terbinafine hydrochloride tablets that you take by mouth, though other formulations like Lamisil spray are also available.
So, how does Lamisil work to kill nail fungus? It all comes down to a process called ergosterol synthesis. Ergosterol is a crucial part of a fungus’s cell membrane, and terbinafine works by blocking squalene epoxidase, a key enzyme needed to create that ergosterol. Without ergosterol, the fungal cell membrane weakens and the fungus dies. That’s why terbinafine is considered a fungicidal drug, which means it actively kills the fungus instead of just slowing its growth.
Uses and Dosage of Lamisil for Nail Fungus
Lamisil (terbinafine) is a prescription antifungal medication primarily used to treat onychomycosis, which is a fungal infection of the toenails or fingernails.
Approved Uses: Onychomycosis
Lamisil is specifically designed to target infections caused by dermatophytes, a common type of fungus that affects the nails.
Dosage Recommendations
The typical dosage of Lamisil for onychomycosis is as follows:
- Fingernail onychomycosis: One 250 mg tablet taken daily for 6 weeks.
- Toenail onychomycosis: One 250 mg tablet taken daily for 12 weeks.
It’s important to remember that even after the fungal infection is gone (mycological cure), it may take several months to see a noticeable improvement in the appearance of your nails. The damaged nail needs time to grow out and be replaced by a healthy nail.
It’s also crucial to take the medication exactly as prescribed by your doctor and to complete the full course of treatment, even if your nails start to look better before the treatment is finished.
Off-Label Uses
While Lamisil is mainly prescribed for nail fungus, doctors may sometimes prescribe it “off-label” to treat other fungal infections, including:
- Tinea pedis (athlete’s foot)
- Tinea corporis (ringworm)
- Tinea cruris (jock itch)
Off-label use means the drug is being used to treat a condition that it hasn’t been specifically approved for by the FDA. Doctors can do this if they believe it’s the best course of treatment for their patient.
What are the possible side effects of Lamisil?
Like any medication, Lamisil has the potential to cause side effects. It’s important to be aware of these before starting treatment, and to discuss any concerns with your doctor.
Common Side Effects
Some of the more common side effects of Lamisil include:
- Gastrointestinal issues: This can mean diarrhea, upset stomach, abdominal pain, or nausea. In clinical trials, diarrhea was reported in 5.6% of people taking Lamisil, compared to 2.9% taking a placebo. Upset stomach was reported in 4.3% of those taking Lamisil, compared to 2.9% taking a placebo.
- Headache: In clinical trials, headaches were reported in 12.9% of people taking Lamisil, compared to 9.5% taking a placebo.
- Skin reactions: This includes rash, itching (pruritus), and hives (urticaria).
- Taste disturbances: Some people experience changes in their sense of taste.
Serious Side Effects (Less Common)
While less common, Lamisil can also cause more serious side effects. These include:
- Hepatotoxicity: This refers to liver damage, which can range from elevated liver enzymes to liver failure. Your doctor will likely monitor your liver function with blood tests while you’re taking Lamisil.
- Severe skin reactions: In rare cases, Lamisil can cause severe skin reactions like Stevens-Johnson Syndrome and toxic epidermal necrolysis.
- Hematologic effects: This involves problems with blood cells, such as neutropenia (low white blood cell count) and thrombocytopenia (low platelet count).
- Taste and smell disturbances: Some people experience a loss of taste and/or smell.
- Depressive symptoms: Lamisil has been linked to depression in some individuals.
Postmarketing Experience
After a drug is released to the public, doctors and patients can report adverse reactions. These reports have linked Lamisil to a variety of issues, including hair loss (alopecia), allergic reactions, and musculoskeletal problems.
Important Considerations
It’s crucial to contact your doctor immediately if you experience any unusual symptoms while taking Lamisil.
Lamisil should be stopped right away if you develop liver problems, taste or smell disturbances, or severe skin reactions.
Lamisil and other medications
Lamisil, like many medications, can interact with other drugs you might be taking. It’s important to understand these potential interactions to avoid unwanted side effects or reduced effectiveness of your treatments.
CYP450 enzyme interactions
Lamisil can interact with drugs that are metabolized by a group of enzymes called CYP450. These enzymes are responsible for breaking down many medications in your body.
Specifically, Lamisil can inhibit CYP2D6, which means it can slow down the breakdown of drugs that rely on this enzyme. This can lead to increased levels of those drugs in your system, potentially causing side effects.
Examples of specific drug interactions
Here are a few examples of medications that can interact with Lamisil:
- Some antidepressants
- Some beta-blockers used to treat high blood pressure
- Some antiarrhythmics used to treat irregular heartbeats
This isn’t a complete list, so it’s always best to consult a drug interaction checker or talk to your doctor or pharmacist to get a comprehensive list and understand the specific risks.
Why it’s important to disclose all medications
When you’re prescribed Lamisil, it’s crucial to tell your doctor about all the medications and supplements you’re taking. This includes:
- Prescription drugs
- Over-the-counter medications
- Herbal remedies
- Vitamins and supplements
By providing a complete list, your doctor can assess the potential for interactions and adjust your treatment plan accordingly. This helps ensure that Lamisil is safe and effective for you.
What to know before you take Lamisil
Lamisil is a strong medication, and it’s not right for everyone. Here are some warnings and precautions to keep in mind.
Contraindications
Don’t take Lamisil if you:
- Have chronic or active liver disease
- Have kidney problems
- Are allergic to terbinafine
Hepatotoxicity
Lamisil can cause liver damage, so it’s important to have your liver function tested while you’re taking it. If those tests come back abnormal, you’ll need to stop taking Lamisil.
Taste and smell disturbances
Some people who take Lamisil experience changes in their sense of taste and smell, including a complete loss of taste or smell. These effects can last for a long time in some cases, so it’s important to be aware of this potential side effect.
Skin reactions
Although rare, some people have had serious skin reactions, like Stevens-Johnson Syndrome or toxic epidermal necrolysis, while taking Lamisil. Stop taking Lamisil and contact your doctor immediately if you develop a skin rash.
Other precautions
Talk to your doctor before taking Lamisil if you have a history of:
- Depression
- Blood disorders
- Lupus
This information is not exhaustive, and it’s important to discuss all of your health conditions and medications with your doctor before starting Lamisil. They can help you determine if Lamisil is the right choice for you and monitor you for any potential side effects.
Lamisil use in specific populations
Before you take any medication, it’s important to understand how it could affect you, especially if you’re in a specific population.
Pregnancy
If you’re pregnant, talk with your doctor about the risks and benefits of Lamisil. Animal studies can give us some insight into potential risks, but they aren’t always applicable to humans.
The FDA puts Lamisil in Pregnancy Category B, meaning that animal reproduction studies have not demonstrated risk to the fetus, and there aren’t adequate and well-controlled studies in pregnant women.
Nursing mothers
Terbinafine, the active ingredient in Lamisil, passes into breast milk. You and your doctor will need to consider whether the benefits of breastfeeding outweigh the risks to your baby.
Children
We don’t know if Lamisil is safe and effective for kids. More research is needed.
Older adults
If you’re an older adult, use Lamisil cautiously. Talk with your doctor about any other medical conditions you have and any other medications you’re taking.
Kidney problems
If you have significant kidney impairment, you shouldn’t use Lamisil.
Patient Counseling Information and Actionable Tips
If your doctor prescribes Lamisil for your fungal nail infection, it’s important that you take it exactly as prescribed and for the entire length of time your doctor recommends. Don’t stop taking it just because your nail looks better! It can take several months to fully clear a nail infection, and stopping too soon can cause it to come back.
It’s also important to be aware of potential side effects and what to do about them. Tell your doctor right away if you experience any unusual symptoms, such as:
- Signs of liver problems
- Changes in your sense of taste or smell
- Skin rashes
While you’re taking Lamisil, try to limit your sun exposure. And make sure your doctor knows about all the other medications and supplements you’re taking, as Lamisil can interact with some of them. Your doctor may also want to monitor your liver function and blood counts while you’re on the medication.
Frequently Asked Questions
What is the best antifungal pill for toenail fungus?
There’s no single “best” antifungal pill for everyone. Lamisil (terbinafine), itraconazole, and fluconazole are common options, but the best choice depends on factors like the severity of the infection, potential drug interactions, and your overall health. A doctor can assess your situation and recommend the most appropriate medication.
When should you not use Lamisil?
Lamisil isn’t suitable for everyone. You shouldn’t use it if you have a history of liver problems, kidney disease, or certain autoimmune disorders. It can also interact with other medications, so it’s crucial to discuss your entire medical history with your doctor before starting Lamisil.
How long do you take Lamisil for toenail fungus?
The typical course of Lamisil for toenail fungus is around 12 weeks. However, the exact duration can vary depending on the severity of the infection and how quickly your nails grow. It’s essential to complete the full course of treatment, even if your nails appear clear before the end.
What is the success rate of Lamisil for toenail fungus?
Lamisil boasts a relatively high success rate, with studies showing that it can effectively clear toenail fungus in approximately 60-70% of cases. However, recurrence is possible, so maintaining good foot hygiene after treatment is important.
Why does Vicks VapoRub work on nail fungus?
While Vicks VapoRub isn’t a proven antifungal treatment, some people find it helpful for managing nail fungus symptoms. It contains ingredients like camphor, eucalyptus oil, and menthol, which may have mild antifungal properties and can help soften the nail, allowing for better penetration of other treatments. However, it’s generally not as effective as prescription antifungals.
Putting It All Together
Lamisil (terbinafine) is a drug that can be used to treat nail fungus. It’s effective, but it’s important to know about potential side effects and drug interactions before you take it.
If your doctor prescribes Lamisil, follow their instructions exactly, and make sure they monitor you carefully. Nail fungus can be difficult to treat, so it’s important to get medical advice and stick to the treatment plan.