Warnings and Precautions With Terbinafine
To help ensure a safe treatment process, you should understand a drug's warnings and precautions. With terbinafine, you should be aware that several side effects are possible, including liver failure, life-threatening skin rashes, lupus, low blood cell counts, or vision changes. Warnings and precautions with terbinafine also extend to people who are allergic to terbinafine or to any components used to make the drug.
You should talk with your healthcare provider prior to taking terbinafine hydrochloride (Lamisil®) if you have:
- Liver disease, including cirrhosis
- Kidney disease or kidney failure
- A poorly functioning immune system (such as with HIV or cancer)
- Systemic lupus erythematosus (SLE or lupus for short)
- Any allergies, including allergies to foods, dyes, or preservatives.
Also let your healthcare provider know if you:
- Are pregnant or thinking of becoming pregnant
- Are breastfeeding.
It's important to also tell your healthcare provider about all other medicines you may be taking, including prescription and non-prescription medicines, vitamins, and herbal supplements.
Precautions and warnings to be aware of before taking terbinafine include the following:
- Terbinafine can interact with certain medications (see Drug Interactions With Terbinafine).
- Terbinafine is considered a pregnancy Category B medication. This means that terbinafine is likely safe for use during pregnancy. However, using of the drug during pregnancy is not recommended, since the full risks are not known and the treatment of nail fungus can be postponed until after pregnancy. Be sure to discuss the possible risks with your healthcare provider before using terbinafine during pregnancy.
- Terbinafine is passed through breast milk. Therefore, if you are breastfeeding or plan to start breastfeeding, be sure to talk with your healthcare provider about this. He or she can decide whether taking terbinafine while nursing would be OK for your particular situation.
- There have been rare cases of terbinafine causing liver failure. Some of these people required a liver transplantation or died as a result. This is more likely to happen in people with existing liver disease. Your healthcare provider should check your liver function (using blood tests) before you start the drug. Also, you should tell your healthcare provider right away if you have any possible symptoms of liver problems, including:
- Yellow eyes or skin
- Dark urine
- Pain in the upper-right abdomen.
Terbinafine can cause life-threatening skin rashes (known medically as Stevens-Johnson syndrome). Call your healthcare provider right away if you experience an unexplained rash that does not go away, especially if the rash involves blisters or peeling of the skin. Also let your healthcare provider know if you have other signs of an allergic reaction, including itching, wheezing, or difficulty breathing or swallowing.
- Terbinafine can cause a loss of taste or smell, or other changes in tasting or smelling. This can be a very disturbing problem that may go away or may become permanent. If these side effects occur, let your healthcare provider know. You will probably need to stop taking terbinafine.
- Terbinafine has not been studied in patients with poorly functioning kidneys. Therefore, if you have kidney problems, discuss this with your healthcare provider before starting terbinafine.
- There have been reports of terbinafine causing lupus or making it worse. Lupus is a condition involving skin rashes (typically a "butterfly" rash on the face) and other serious problems. If you develop symptoms of lupus, or if your lupus gets worse while taking terbinafine, you should stop taking the medication and call your healthcare provider.
- In rare cases, terbinafine has caused vision changes. Let your healthcare provider know if you have any changes in your vision, including blurred or double vision.
- If your immune system is not functioning well (such as in people with HIV/AIDS, cancer, or other conditions) and you have taken terbinafine for longer than six weeks, you should have blood tests done to make sure that your blood counts are not decreasing too much.
- Terbinafine can cause certain blood cell counts to decrease, putting you at risk for infection. If you have an unusual infection (or if you have more infections than normal), talk to your healthcare provider about the possibility of low blood cell counts.