Pharmacokinetics of perhexiline maleate in anginal patients with and without peripheral neuropathy

Perhexiline maleate (Pexid) which has been in general use in France with good results for the treatment of angina pectoris since 1973, may be associated with severe side effects including peripheral neuropathy. The present study is a comparison of the pharmacokinetics of perhexiline maleate in anginal patients with and without signs of peripheral neuropathy. Compared to the latter, those with neuropathy had higher plasma levels of perhexiline, slower hepatic metabolism and a longer plasma half-life. Thus, peripheral neuropathy associated with perhexiline maleate treatment appears to be a direct toxic effect due to accumulation of the drug. The accumulation might result either from a decreased volume of distribution secondary to a loss of body weight, possibly drug-induced, or to slow hepatic metabolism of perhexiline of genetic origin or due to hepatic disease, possibly drug-induced. The neuropathy is rarely an isolated event, as it is often associated with one or more adverse effects of perhexiline.