Mass treatment of onchocerciasis with ivermectin: should people with epilepsy and/or growth-retardation syndromes be excluded?

In many areas of Africa where human onchocerciasis is endemic there are now programmes for mass treatment with ivermectin (Mectizan), to eliminate the disease as a public-health problem. To determine whether those with epilepsy and/or growth-retardation syndromes (GRS) should be excluded from such mass drug administrations, literature searches of the standard biomedical databases were performed for all relevant articles published in English or French before January 2003. Cross-referencing and the retrieving of articles recommended by experts completed the search. The literature review revealed that there is insufficient evidence for an association between onchocerciasis and epilepsy or GRS. Since ivermectin does not normally cross the blood-brain barrier, the drug is unlikely to have direct pro- or anti-convulsive activity. Furthermore, an estimated 1-2 million epileptics in Africa have been treated with ivermectin, in onchocerciasis-control programmes, without any reports of serious adverse events (SAE) to the passive surveillance system for such events. As there are few data on the prevalence of GRS in Africa, it is difficult to estimate the number of GRS cases who have been treated with ivermectin or the incidence of ivermectin-related SAE among such cases. Epileptics should not be excluded from mass treatments with ivermectin unless they are actively seizing or postictal. Although those with GRS associated with chronic wasting, with or without epilepsy, should be excluded, they should be eligible for clinic-based treatment if the diagnosis of onchocerciasis is confirmed and the benefits of treatment are deemed to outweigh any potential risks.