The State's drug safety body has reminded doctors to exercise caution when prescribing a drug commonly used to treat fungal infections of the skin and nails.
In its latest drug safety newsletter, the Irish Medicines Board (IMB) said it had received almost 100 reports of suspected adverse reactions to terbenafine since it was first authorised for oral use in the early 1990s. Terbenafine is marketed under the trade name Lamisil.
Among the reactions recorded were inflammation of the liver which the newsletter says may occur "with or without pre-existing liver disease".
Last month, the IMB suspended the licence of the non-steroidal anti-inflammatory medication nimesulide, after it emerged that nine patients had developed liver failure while taking the drug.
A number of patients have died from liver failure linked to nimesulide; last week a coroner's court in Cork heard that a 71-year-old Waterford woman, Joan Flavin, had died from liver failure while taking the anti-inflammatory agent.
While it is understood that no case of liver failure here has been attributed to terbenafine, the manufacturer's summary of product characteristics (SPC) lists liver disorders as a "rare" undesirable effect. It says that very rare cases of serious liver failure, including some with a fatal outcome or requiring a liver transplant, have occurred.
"Very rare" side effects occur in less than one in 10,000 people taking a drug.
The IMB drug safety newsletter reminds doctors that oral terbenafine is not recommended in patients with acute or chronic liver disease.
Patients prescribed terbenafine should be warned to report immediately any symptoms of unexplained persistent nausea, anorexia, vomiting, right upper abdominal pain, or jaundice, dark urine or pale stools. They should discontinue taking oral terbenafine and the patient's liver function should be immediately evaluated.
The Irish Times understands that most of the 97 adverse reactions associated with the anti-fungal drug and reported to the IMB were minor side effects such as headache and tummy upset. Experts said that while terbenafine can have liver side effects, the drug was not "in the same league" as nimesulide.
However, other potentially serious reactions to the drug such as anaemia and systemic lupus erythematosus (SLE) have been reported to the IMB.
SLE is an inflammatory connective tissue disorder that can affect joints, kidneys and the walls of blood vessels. In addition, a number of allergy-related side effects have been linked to the use of oral terbenafine.
The drug is recommended for the treatment of ringworm (tinea corporis and tinea pedis) as well as fungal nail infections. Fungal skin infections usually respond to a four-week course of terbenafine given at 250mg daily, while some deep seated fungal nail infections may require six months' treatment with the drug.