Thalidomide in human immunodeficiency virus (HIV) patients. A review of safety considerations

The sedative thalidomide was withdrawn from the market 30 years ago because of its teratogenic and neurotoxic adverse effects. The compound was later discovered to be extremely effective in the treatment of erythema nodosum leprosum, a complication of lepromatous leprosy. This effect is probably due to a direct influence on the immune system, because thalidomide possesses no antibacterial activity. The compound is presently used as an experimental drug in the treatment of a variety of diseases with an autoimmune character, including recurrent aphthosis of nonviral and nonfungal origin in human immunodeficiency virus (HIV) patients. This article reviews the most important chemical and pharmacokinetic properties of thalidomide. The possible mechanisms of the nonsedative effects of thalidomide with respect to the safety of its use in HIV patients are discussed. Because the mechanism of the immunomodulatory effect of thalidomide is unknown, the possibility that the administration of this compound will accelerate the deterioration of the immunological status of HIV patients cannot be excluded. Clinical evidence suggests that thalidomide may aggravate the condition of patients with preexisting peripheral neuropathy. Hypersensitivity reactions to thalidomide may occur more frequently in HIV patients than in other patient groups. Because of the teratogenic activity of thalidomide, reliable contraception must be provided to female patients of childbearing age. Before the introduction of thalidomide therapy to an HIV patient presenting with oral ulcers, a fungal or viral origin of the lesions should be excluded. Thalidomide should not be used in patients with preexisting HIV-related peripheral polyneuropathy, polyradiculopathy or encephalopathy. In patients experiencing a complete remission, the discontinuation of thalidomide treatment and its reintroduction in the case of a relapse are preferable to maintenance therapy.