Concerns About Taking Antifungal Medication for Nail Fungus

Q: Concerns About Taking Antifungal Medication for Nail Fungus

Hello, Qingtian： Regarding your inquiry about Lamisil (terbinafine), its indications include (1) onychomycosis, (2) tinea capitis, and (3) extensive dermatophyte infections that have not responded to topical treatment, but it is ineffective against tinea versicolor. <br>Onychomyc

Onychomycosis medication issues?

I recently visited a doctor for a nail condition, and they prescribed a medication called Terbinafine tablets.
I looked it up online, and it seems to be used for treating onychomycosis (fungal nail infection), which my nails appear to have.
I didn't pay much attention to what the doctor said at the time, but I read that doctors usually check liver function by drawing blood before prescribing this medication.
However, my doctor didn't draw blood; they only asked me some questions about my medication history.
Is it necessary to have blood tests before taking this medication, or did the doctor forget? I've been taking it for a few days without any discomfort.
If I continue taking it without having had blood tests, could that be inappropriate? I don't have any liver diseases or history.

Qing Tian, 20~29 year old female. Ask Date: 2008/09/15

Dr. Zhang Zhibo reply Dermatology

Hello, Qingtian: Regarding your inquiry about Lamisil (terbinafine), its indications include (1) onychomycosis, (2) tinea capitis, and (3) extensive dermatophyte infections that have not responded to topical treatment, but it is ineffective against tinea versicolor.
Onychomycosis requires treatment for 6-12 weeks (6 weeks for fingernails, 12 weeks for toenails).
If persistent vomiting without an obvious cause, loss of appetite, or fatigue occurs after taking the medication, liver function should be checked immediately.
If brown urine, pale stools, or jaundice develops, the medication must be stopped immediately, and liver function should be assessed.
Patients with a history of chronic liver dysfunction or acute hepatitis should be informed that liver impairment may present with the aforementioned symptoms before taking this medication, and it is advisable to check liver function beforehand.
A mildly elevated liver enzyme level (generally less than twice the normal value) can often be due to fatty liver, which is not an absolute contraindication for taking Lamisil.
Therefore, some physicians may prescribe the medication after inquiring about any past liver disease history, and if the side effects mentioned occur, they will stop the medication and check for liver damage, which is usually reversible.

Additionally, here are some common side effects associated with Lamisil for your reference: the most frequent side effect is headache (occurring in 12.9% of patients); gastrointestinal symptoms include diarrhea (5.6%), abdominal discomfort (4.3%), taste disturbances (2.8%), nausea (2.6%), abdominal pain (2.4%), and bloating (2.2%); other symptoms include rash (5.6%), itching (2.8%), urticaria (1.1%), and abnormal liver enzyme results (3.3%).
In some cases, the incidence of these side effects is not higher than that in patients taking a placebo (sugar pill).
If these side effects occur, consideration may be given to using another class of antifungal medication, such as Sponorax, or topical antifungal nail lacquer like Penlac.

Reply Date: 2008/09/15

More Info

When it comes to taking antifungal medication for nail fungus, particularly Terbinafine (known as Lamisil), there are several important considerations to keep in mind. Terbinafine is an effective oral antifungal medication commonly prescribed for onychomycosis, or nail fungus, due to its ability to penetrate the nail bed and eliminate the fungal infection. However, it is crucial to monitor liver function during treatment, as the drug can affect liver enzymes.

Your concern about not having a blood test to check liver function before starting Terbinafine is valid. Typically, healthcare providers will assess liver function through blood tests, especially if the patient has risk factors for liver disease or is taking medications that can affect the liver. This is because Terbinafine is metabolized by the liver, and elevated liver enzymes can indicate potential liver damage or dysfunction.
If your doctor did not perform a blood test before prescribing the medication, it could be due to several reasons. They may have assessed your medical history and determined that you do not have any risk factors for liver disease, or they may have felt that the benefits of starting treatment outweighed the risks at that moment. However, it is always best practice to have liver function tests done before starting any medication that can impact liver health, particularly if you are on other medications or have any underlying health conditions.

Since you mentioned that you have been taking the medication for a few days without any adverse effects, this is a positive sign. However, it is essential to remain vigilant for any symptoms that may indicate liver issues, such as jaundice (yellowing of the skin or eyes), dark urine, pale stools, fatigue, or abdominal pain. If you experience any of these symptoms, you should contact your healthcare provider immediately.

Continuing to take Terbinafine without a prior liver function test is not necessarily unsafe, especially if you have no history of liver disease. However, it is advisable to discuss your concerns with your healthcare provider. They may recommend performing a liver function test while you are on the medication to ensure that your liver is handling the drug appropriately.
In summary, while it is generally safe to continue taking Terbinafine if you have no liver issues, it is crucial to have regular follow-ups with your healthcare provider. They can monitor your health and make any necessary adjustments to your treatment plan. If you have any lingering concerns or questions about your treatment, do not hesitate to reach out to your doctor for clarification and guidance. Your health and safety should always be the top priority when undergoing any medical treatment.

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