In one clinical study, the monthly prevalence of nervous system symptoms of at least moderate severity between weeks 4 and 48, ranged from 5% - 9% in patients treated with regimens containing efavirenz and 3% - 5% in patients treated with the control regimen.
Ühes kliinilises uuringus oli vähemalt keskmise raskusega närvisüsteemipoolsete sümptomite esinemissagedus 4… 48. ravinädalal 5… 9% efavirensi saanud patsientidel ning 3… 5% kontrollrühmas.