Deltoid Administration of LAI-ART: Pharmacokinetic Implications When the Gluteal Site Is Not Feasible

This case report describes the use of long-acting injectable (LAI) antiretrovirals administered via an alternative injection site in an individual with HIV who was unable to receive intramuscular gluteal injections. Specifically, it focuses on intensive pharmacokinetic monitoring following deltoid administration of LAI rilpivirine and cabotegravir in a 29-year-old transgender woman with progressive multifocal leukoencephalopathy and swallowing difficulties. Gluteal injection was contraindicated due to prior silicone injections in that region. Peak plasma concentrations were reached on day 3 post-injection for both drugs, with cabotegravir peaking at 1278 ng/mL and rilpivirine at 30 ng/mL. Rilpivirine plasma levels declined more rapidly than cabotegravir levels. By day 10, the patient's clinical condition had deteriorated, leading to hospice care and subsequent death. Rilpivirine exposure after deltoid injection appeared lower than that typically reported after gluteal or thigh administration, although intracellular drug concentrations may differ from plasma levels, potentially mitigating clinical concerns.