Drug efficacy developing countries

This important antifungal drug (see Chapter 48) is an alternative therapy for visceral leishmaniasis, especially in parts of India with high-level resistance to sodium stibogluconate. Liposomal amphotericin has shown excellent efficacy at a dosage of 3 mg/kg/d intravenously on days 1-5, 14, and 21. Nonliposomal amphotericin (1 mg/kg intravenously every other day for 30 days) is much less expensive, also efficacious, and widely used in India. Amphotericin is also used for cutaneous leishmaniasis in some areas. The use of amphotericin, and especially liposomal preparations, is limited in developing countries by difficulty of administration, cost, and toxicity. 

Because it is cheap and of unquestioned efficacy, phenobarbital is stiU widely prescribed around the world, although in developed countries its use has fallen since the introduction of drugs that are better tolerated. Its most common adverse effects are sedation (to which partial tolerance develops), cognitive dysfunction, and in children hyperkinesia and other behavioral disturbances. 

The broad-spectrum anthelmintic nitazoxanide has been undergoing efficacy trials in the USA for the treatment of EPM (Vatistas et al 1999). This drug is currently used to combat intestinal parasites of humans in developing countries and in patients with the acquired immimodeficiency syndrome complicated by secondary protozoal infections. Nitazoxanide is administered daily for 28 days as an oral paste. The side-effects of this drug are more serious than with other medications because it kills other parasites in addition to S. neurona. This has led to recommendations for deworming with another anthelmintic prior to starting this treatment (McClure Palma 1999). Nitazoxanide may also cause colic in treated horses. 

Two second-generation rotavirus vaccine candidates (one composed of five human-animal reassortants, RotaTeq , and the other a monovalent attenuated human rotavirus vaccine, Rotarix ) were in development in 1999, and after 7 years of study, they were licensed by the European Medicines Agency (EMA), the Food and Drug Administration (FDA), and many other licensing authorities. Both vaccines are efficacious and both underwent extensive safety trials in more than 130000 children, in whom there was no association with intussusception. In the years since licensing, there have been substantial reductions in the rates of hospitalization and death from rotavirus in both developed and less-developed countries. As part of post-licensing safety follow-up, the possible effect of the widespread use of rotavirus vaccines on rates of intussusception has been monitored carefully [2V]. 

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