Single versus Multiple Dose Ivermectin Regimen in Onchocerciasis-Infected Persons with Epilepsy Treated with Phenobarbital: A Randomized Clinical Trial in the Democratic Republic of Congo.

BACKGROUND

There is anecdotal evidence that ivermectin may decrease seizure frequency in Onchocerca volvulus-infected persons with epilepsy (PWE).

METHODS

In October 2017, a 12-month clinical trial was initiated in rural Democratic Republic of Congo. PWE with onchocerciasis-associated epilepsy experiencing ≥2 seizures/month were randomly allocated to receive, over a one-year period, ivermectin once or thrice (group 1), while other onchocerciasis-infected PWE (OIPWE) were randomized to ivermectin twice or thrice (group 2). All participants also received anti-epileptic drugs. Data was analyzed using multiple logistic regression.

RESULTS

We enrolled 197 participants. In an intent-to-treat analysis (data from group 1 and 2 combined), seizure freedom was more likely among OIPWE treated with ivermectin thrice (OR: 5.087, 95% CI: 1.378-19.749; p = 0.018) and twice (OR: 2.471, 95% CI: 0.944-6.769; p = 0.075) than in those treated once. Similarly, >50% seizure reduction was more likely among those treated with ivermectin twice (OR: 4.469, 95% CI: 1.250-16.620) and thrice (OR: 2.693, 95% CI: 1.077-6.998). Absence of microfilariae during the last 4 months increased the odds of seizure freedom (p = 0.027).

CONCLUSIONS

Increasing the number of ivermectin treatments was found to suppress both microfilarial density and seizure frequency in OIPWE, suggesting that O. volvulus infection plays an etiological role in causing seizures.