The first gene ever to resist Effavirenz, a type of drug used in the treatment of human immunodeficiency virus (HIV) type 1, has been discovered by researchers from Mahidol University's Faculty of Medicine at Ramathibodi Hospital, reports said on Monday.
"This is the first discovery [of gene CYP2B6]. The researchers have already applied for patent registration. The study shows the relationship of the gene with the level of Effavirenz concentration. Patients with high Effavirenz concentration in their blood suffer from neural toxicity," said Dr Chonlapat Sukasem, the hospital's head of the Division of Pharmacogenomics.
The situation can cause nightmares, depression and other effects. It can even drive patients to commit suicide, he added.
Dr Chonlapat, also head of the Department of Pathology, revealed that HIV patients with gene CYP2B6 can only get a small amount of Effavirenz out of their systems after taking it, exposing them to the risk of neural toxicity.
However, if the patients' doses are too small, the drug becomes ineffective and leads to HIV mutation which causes further problems, he said.
He advised the Government Pharmaceutical Organisation to manufacture 100-200mg Effavirenz tablets instead of the standard 600mg only for patients who might require more or less dosages.
Patients currently have to break pills in half to reduce or increase their dosage but this practice can cause dangerous side effects due to inappropriate levels.
Dr Chonlapat warned that if the gene CYP2B6 is transferred from one patient to another, that recipient will also be resistant to Effavirenz. When this scenario happens, new and more expensive medications have to be applied, which can affect the country's overall public health situation.
He urged the National Health Security Office to cover the cost of gene scans and Effavirenz concentration tests.