Fingernail fungus, also called onychomycosis, is a common condition. It can make your nails thick, discolored, and brittle. If you’ve ever had it, you know it can be stubborn and difficult to get rid of.
One treatment option your doctor might suggest is Lamisil. Lamisil is the brand name for terbinafine hydrochloride, an oral antifungal medication. While there are topical treatments for nail fungus, they don’t always work as well, especially for toenail fungus.
Lamisil tablets contain terbinafine hydrochloride, an effective oral antifungal medicine. Generic versions are also available, but this article will refer to the brand name Lamisil.
If your doctor prescribes Lamisil for fingernail fungus, it’s important to understand how it works, how to take it, and what side effects to watch out for. This article will give you a complete look at Lamisil, including how it’s used, the right dosage, potential side effects, and precautions to take.
It’s important to remember that you need a prescription for Lamisil tablets. Before you start taking terbinafine, talk to your doctor about your health history. They can help you decide if Lamisil is the right choice for you and monitor you for any potential problems.
What is onychomycosis?
Onychomycosis is just the medical term for a fungal infection of the nail. These infections are usually caused by organisms called dermatophytes.
If you have a fungal infection in your fingernails, you might notice:
- the nail getting thicker
- changes in color, such as yellow or brown
- the nail becoming brittle or crumbly
- the nail’s shape distorting
Who’s at risk for onychomycosis?
Some things that can increase your chances of getting a nail infection are:
- injuring your nail
- having diabetes
- having a weak immune system
- poor hygiene
- spending time in moist environments like swimming pools and showers
How to prevent nail infections
To reduce the risk of getting onychomycosis, you can:
- keep your nails clean and dry
- avoid sharing nail clippers and files
- wear shoes and socks that let your feet breathe
- treat athlete’s foot promptly
How Lamisil works
Lamisil is the brand name for the antifungal medicine terbinafine. To understand how Lamisil works, it helps to know a little about fungi and fungal infections.
Fungi are living organisms, just like plants and animals. Fungi can cause infections, such as athlete’s foot, ringworm, and fungal nail infections, all of which could potentially benefit from a fungi cure wash as well. Fungal nail infections can be difficult to treat because the fungus lives under the nail, where it’s hard to reach with topical medications.
How terbinafine attacks fungus
Terbinafine, the active ingredient in Lamisil, works by blocking an enzyme called squalene epoxidase. This enzyme is essential for fungi to make ergosterol, a key building block of their cell membranes. Without ergosterol, the fungal cell membranes become weak and leaky, eventually causing the fungal cell to die.
How your body handles terbinafine
When you take Lamisil orally, your body absorbs more than 70% of the drug. It then travels through your bloodstream, attaching to proteins. In fact, more than 99% of terbinafine molecules bind to proteins in your blood.
Terbinafine spreads throughout your body, with a volume of distribution (Vd) of about 2000 liters. It’s broken down (metabolized) by enzymes called CYP450. Your body gets rid of terbinafine through your urine (about 70%). The half-life of terbinafine is around 36 hours, meaning it takes that long for half of the drug to leave your system.
Dosage and Administration of Lamisil for Fingernail Fungus
If your doctor prescribes Lamisil for your fingernail fungus, they’ll likely tell you to take one 250 mg tablet by mouth, once per day. Typically, you’ll need to take it for six weeks if it is a fingernail infection.
It’s really important to take Lamisil exactly as your doctor prescribes it. Don’t stop taking it early, even if your nails start to look better. You need to complete the full course of treatment to kill the fungus completely.
Keep in mind that you might not see the full effect of the medication for several months after the fungus is gone. It takes time for the healthy nail to grow back.
If you have kidney problems (specifically, if your creatinine clearance is less than 50 mL/min), then Lamisil isn’t for you. Be sure to tell your doctor about any kidney issues before starting this medication, so they can consider other treatment options.
Potential Side Effects of Lamisil
Like all medications, Lamisil can cause side effects. Most of them are mild, but some can be serious. If you’re considering this medicine, it’s important to know what to watch out for.
Common Side Effects
The most common side effects of oral Lamisil include:
- Headache (13%)
- Diarrhea (6%)
- Upset stomach (4%)
- Rash (6%)
- Itching (3%)
- Nausea (3%)
- Changes in taste or smell
Serious Side Effects
Although less common, Lamisil can cause some serious side effects that require immediate medical attention. These include:
- Liver damage (hepatotoxicity)
- Severe skin reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis)
- Allergic reactions (DRESS syndrome)
- Blood disorders (low lymphocytes/neutrophils)
- Depressed mood
- Lupus
- Thrombotic microangiopathy (TMA)
If you experience any of these, stop taking Lamisil and contact your doctor right away.
Importance of Liver Function Monitoring
Because Lamisil can sometimes affect the liver, your doctor will likely want to monitor your liver function during treatment.
A finger-prick blood test for liver function is required after 4 weeks of treatment.
Your doctor may also advise that you have regular blood tests to check your complete blood count.
It’s also important to be aware of the symptoms of liver problems. Contact your doctor immediately if you experience any unusual symptoms, such as:
- Nausea
- Vomiting
- Fatigue
- Loss of appetite
- Yellowing of the skin or eyes (jaundice)
- Dark urine
- Pale stools
- Stomach pain
Drug interactions with Lamisil
Lamisil interacts with some other medications. This means that when you take Lamisil, it can change the way another drug works in your body, or the other drug can change how Lamisil works. These interactions can sometimes cause side effects or make a medication less effective.
CYP450 enzyme interactions
Lamisil interacts with CYP450 enzymes, which are important for metabolizing many drugs. This interaction can cause problems when Lamisil is taken with drugs like:
- Antidepressants
- Beta-blockers
- MAO-B inhibitors
- Some other antifungals
- Blood thinners
Contraindicated medications
Some medications should not be taken with Lamisil. For example, you shouldn’t take Lamisil if you have:
- Kidney problems (specifically, if your creatinine clearance is less than 50 mL/min)
- Chronic or active liver disease
Talk to your doctor
Before you start taking Lamisil, be sure to tell your doctor about everything you’re already taking. That includes prescription drugs, over-the-counter medicines, and even supplements.
Your doctor needs to know about all the drugs you’re taking so they can check for potential interactions and make sure Lamisil is safe for you.
It’s always a good idea to keep a current list of all your medications and supplements. That way, when you visit the doctor, you can easily share the information they need to make the best decisions about your health.
Warnings and Precautions for Lamisil Use
Just like any medication, Lamisil comes with warnings and precautions that you should know about before starting treatment.
Contraindications
You should not take Lamisil if you have:
- Chronic or active liver disease
- Renal impairment (CrCl <50 mL/min)
Precautions
Talk with your doctor about whether Lamisil is right for you if you have any of the following:
- Liver problems: Lamisil can sometimes cause liver damage. Your doctor may want to monitor your liver function while you’re taking this medication.
- Taste or smell disturbances: Some people experience a loss of taste or smell while taking Lamisil.
- Mental health issues: Lamisil has been linked to depressive symptoms in some people.
- Sensitivity to sunlight: Lamisil can make your skin more sensitive to the sun, so it’s important to avoid prolonged sun exposure, including tanning beds.
- Blood disorders: Lamisil can sometimes affect your blood cell counts.
- Serious skin reactions: In rare cases, Lamisil can cause serious skin reactions or hypersensitivity.
- Lupus: Lamisil may worsen the symptoms of lupus.
This isn’t a complete list, so be sure to discuss your full medical history with your doctor before taking Lamisil. They can help you weigh the risks and benefits and determine if it’s the right treatment option for you.
Lamisil and special populations
Like all medications, Lamisil poses special risks for certain groups of people.
Pregnancy and breastfeeding
It’s always a good idea to talk with your doctor about medication use during pregnancy. The FDA advises that Lamisil should not be used during pregnancy unless the potential benefits outweigh the potential risks to the unborn baby.
The active ingredients in Lamisil can pass into breast milk. If you’re breastfeeding, talk with your doctor about whether the benefits of breastfeeding outweigh the potential risks to your baby.
Children
The FDA has not established whether Lamisil is safe and effective for children to use.
Older adults
Older adults should use Lamisil with caution.
It’s important to discuss your medical history with your doctor before you begin taking Lamisil. Your doctor can help you understand if Lamisil is the right choice for you.
Alternatives to Lamisil
If Lamisil isn’t the right choice for you, there are other options to consider, including a fungus nail laser treatment. Another oral antifungal medication that your doctor might prescribe is itraconazole (Sporanox) or fluconazole (Diflucan). Like Lamisil, these medications require a prescription.
There are also topical antifungal treatments available, like ciclopirox (Penlac) and efinaconazole (Jublia), or even a fungus nail spray. However, these treatments are generally less effective than oral medications, and it can take much longer to see results, especially when treating toenail fungus.
It’s important to talk with your doctor to figure out the best treatment plan for you. Remember, you’ll need a prescription for Lamisil tablets, so you can discuss your options with your doctor at the same time.
To Conclude
Lamisil (terbinafine) is an oral antifungal medication that can be effective at treating fingernail fungus (onychomycosis). If your doctor prescribes it, it’s important to take it exactly as prescribed and for the full course of treatment.
Like all medications, Lamisil carries some risk of side effects, so it’s important to tell your doctor about your complete medical history before you start taking it. You should also let your doctor know about any other medications you take to avoid drug interactions.
If you think you have a fungal nail infection, talk to your doctor right away. The earlier you diagnose and treat it, the better your chances of getting rid of the infection. Early treatment can also keep the infection from spreading to other nails.