Date of report: 22 Jun 2020
Reported case interaction between
Cobicistat and Paliperidone

FLS Science

Drugs suspected to be involved in the DDI

Drug A
Cobicistat (Perpetrator)
Daily Dose
150 (mg)
Dose adjustment performed
Administration Route
Start date
Jan. 1, 2019
End date
Drug B
Paliperidone (Victim)
Daily Dose
150 (mg)
Dose adjustment performed
Administration Route
Start date
Jan. 1, 2020
End date
Jan. 5, 2020

Complete list of drugs taken by the patient

Antiretroviral treatment
Darunavir (with Ritonavir or Cobicistat)
Complete list of all comedications taken by the patient, included that involved in the DDI
Paliperidone 12mg/d Lorazepam 5mg/d Mirtazapine 30mg/d Levomepromazin 25 mg/d

Clinical case description

eGFR (mL/min)
Liver function impairment
50-year-old HIV positive patient. Multiple virological failures with multi-drug resistant HIV strain, and reduced ARV options. Undetectable on DRV/c + dolutegravir. Clinical history relevant for chronic delusional syndrome treated orally by paliperidone, levomepromazin, mirtazapine and lorazepam. Admitted to psiquiatry depertment due to acute psychotic decompensation. The patient refused oral medication, so intramuscular paliperidone was chosen. The patient received paliperidone 150mg IM at admission, and 100mg IM 4 days later. Clinical response was appropriate, without evidence of paliperidone toxicity. Although paliperidone is primarily eliminated renally, with minimal metabolism occurring via CYP2D6 and CYP3A4, a high IM dose combined with Darunavir/cobicistat could potentially increase paliperidone exposure, and lead to side effects, but they were not seen in our case.


No unwanted outcome

Editorial Comment

This case reveals no unexpected side effects between darunavir/cobicistat and paliperidone. The dose chosen is in the lower rank of the dose recommendation. Interestingly QTc interval monitoring should be recommended in those patients as a potential severe side effect.