Seven day primaquine treatment for P. vivax malaria in India as effective as fourteen day regimen
A multicentre randomised controlled trial in India has found that a seven-day primaquine regimen for the radical cure of Plasmodium vivax malaria is as effective and safe as the currently standard fourteen-day regimen, with patients more likely to complete the full course of treatment. The findings are published in The Lancet Regional Health – Southeast Asia.
India currently recommends a fourteen-day primaquine regimen for preventing P. vivax malaria relapses, while WHO guidelines recommend administering the same total dose over seven days. The new trial provides important India-specific evidence supporting the shorter regimen.
The study was conducted by Indian Council of Medical Research-National Institute of Malaria Research (ICMR-NIMR), in collaboration with municipal corporations and state medical colleges in India, the Infectious Diseases Data Observatory, the Menzies School of Health Research in Australia, and other national and international research partners.
Together, the team carried out an open-label randomised controlled trial in Ahmedabad and Kolkata, India, enrolling 400 patients with uncomplicated P. vivax malaria and normal G6PD activity (a deficiency in this enzyme increases risk of hemolysis with P.vivax treatment). The trial compared outcomes in patients given primaquine over seven days (0.5 mg/kg/day) with outcomes in patients receiving the same total dose of 3.5 mg/kg over fourteen days (0.25 mg/kg/day).
Both groups of patients tolerated the treatment well, with symptoms recurring in only two patients in each group.
Importantly, patients were more likely to take the full dose of treatments in the shorter treatment regimen of seven days: only 8% of patients on seven-day regimen missed a drug dose, compared with 20% missing a dose on the fourteen-day regimen.
“We do think that better adherence to the shorter course is an important factor, and it could improve the effectiveness of radical cure in routine practice,” said study author Professor Kamala Thriemer from the Menzies School of Health Research.
Findings informing Indian national policy discussions
Study author Dr Praveen K. Bharti from ICMR-NIMR (now Director ICMR-NITHR, Jabalpur), said: “These findings provide important evidence to support programmatic decision-making and could strengthen India’s efforts towards malaria elimination.”
Study author Dr. Nitika from ICMR-NIMR, said: “The findings could help inform future updates to India’s treatment guidelines for Plasmodium vivax malaria, while supporting improved treatment compliance.”
These results were also presented at the ICMR-NIMR Symposium on Research for Malaria Elimination 18 December 2025, with an official report of the trial findings being released by the Director of the National Programme in India. Dr Anup Anvikar, ICMR-NIMR Director, said that the existing fourteen-day treatment regimen was a “long-standing operational challenge” in P. vivax malaria management, adding that “Shorter treatment regimens are more feasible to implement and complete under real-world conditions after G6PD testing.”
Professor Philippe Guérin, study author and IDDO Director, said: “Together, these results provide a strong evidence base to inform updates to national treatment guidelines and programme implementation strategies.”