Sporanox and Lamisil are prescription drugs used to treat fungal infections of the toe and fingernail. Sporanox is also approved, in different forms, for treatment of serious fungal infections that may occur in other parts of the body.

Recent studies indicate that Sporanox may weaken the force of the heart’s contractions. This effect was observed when intravenous Sporanox was injected into anesthetized dogs and healthy human volunteers. In these studies, the adverse effect resolved once use of the drug stopped.

Since becoming aware of the study findings, the FDA analysed US and international postmarketing adverse event reports involving Sporanox that were received between its approval in 1992 and April 2001. It received 94 reports in which patients receiving Sporanox developed CHF. In 58 of the 94 cases, the FDA believes Sporanox contributed to or may have been the cause of the CHF. Of these 58 patients, 28 were hospitalized. Although death was reported in 13 of the cases, the causal relationship between the deaths and Sporanox is unclear because of confounding factors.

The advisory also alerts physicians to rare cases of serious liver problems, including liver failure, associated with the use of Sporanox products and Lamisil tablets. Although potential adverse liver effects were already noted in the labelling for both products, the FDA decided to include this information in the advisory because some cases involved patients who had neither pre-existing liver disease nor a serious underlying medical condition. These concerns do not apply to topical versions of Lamisil.