Drug Repositioning: Antimalarial Activities of GABA Analogs in Mice Infected with Plasmodium berghei.

Background: Drug repositioning is becoming popular due to the development of resistance to almost all the recommended antimalarials. Pregabalin and gabapentin are chemical analogs of gamma- aminobutyric acid (GABA) approved for the treatment of epilepsy and neuropathic pain.

Objective: This study investigates acute toxicities and antimalarial activities of pregabalin and gabapentin in the murine malarial model.

Methods: Acute toxicities were assessed using the method of Lorke, while curative activities were assessed by the administration of serial doses of pregabalin and gabapentin to Plasmodium berghei infected mice. Pregabalin was further investigated for its prophylactic activity, and curative potential when combined with either artesunate or amodiaquine. All drugs were freshly prepared and administered orally. Thin films were collected, stained, and observed under the microscope for the estimation of parasitemia and calculation of percentage chemoinhibition or chemoprevention. In pregabalin -artesunate or -amodiaquine combination aspect of this study, survival day post-infection (SDPI) was recorded, while parasitemia was re-estimated for animals that survived till day 28.

Results: The oral LD50 of gabapentin, as well as pregabalin, was >5,000 mg/kg. Gabapentin at 100 and 200 mg/Kg demonstrated 35.64% and -12.78% chemoinhibition, respectively, while pregabalin demonstrated 75.60% and 100.00% chemoinhibition at doses of 12.5 and 25 mg/Kg, respectively. Moreover, pregabalin at individual doses of 25, 50 mg/Kg, and in combination with either artesunate or amodiaquine demonstrated 100.00% chemoinhibition. In its prophylactic study, pregabalin was found to be 100% chemopreventive at individual doses of 12.5 and 25 mg/Kg.

Conclusion: Both GABA analogs have antimalarial properties, but pregabalin proved to be more efficacious.