Date of report 11 Dec 2023
Reported case interaction between
Cobicistat and SILODOSIN

FLS Science

Drugs suspected to be involved in the DDI

Perpetrator
Cobicistat
Daily Dose
150 (mg)
Dose adjustment performed
No
Administration Route
Oral
Start date
April 22, 2022
End date
Ongoing
Victim
SILODOSIN
Daily Dose
8 (mg)
Dose adjustment performed
No
Administration Route
Oral
Start date
Unknown
End date
Ongoing

Complete list of drugs taken by the patient

Antiretroviral treatment
Darunavir/Cobicistat/Emtricitabine/Tenofovir-AF
Complete list of all comedications taken by the patient, included that involved in the DDI

Silodosin 8mg/d atorvastatine 40mg/d paracetamol on demand

Clinical case description

Gender
Male
Age
44
eGFR (mL/min)
>60
Liver function impairment
No
Description

HIV infection diagnosed in 2010, treated by several ART regimens due to different intolerances. DRV/c-FTC-TAF started in 2022 (following intolerance to DTG-3TC) with good tolerance. Some months later, his primary care physician started silodosin 8mg QD due to irritative symptoms of the vessel. Despite the dose exceeding the recommended when it is co-administered with cobicistat, no toxicity was reported. Dose was, anyway, adapted to 4 mg QD in the following HIV visit.

 

 

Clinical Outcome

No unwanted outcome

Editorial Comment

Silodosin is a substrate of CYP3A4 and P-gp, and coadministration with cobicistat is expected to increase silodosin concentrations. Coadministration with ketoconazole (440 mg) increased sidolosin Cmax and AUC by 3.8-fold and 3.2-fold, respectively. Concomitant use of sidolosin with potent CYP3A4 inhibitors is contraindicated (US product label) or not recommended (EU prescribing information). However, given its uroselective effect and wide therapeutic index, silodosin may be used at 4 mg QD (as in this case) with caution and monitoring for side effects such dizziness, of orthostatic hypotension.

University of Liverpool Recommendation

These drugs should not be coadministered
For more information click here

Personal information from the specialist

Name
Juan
Surname
Ambrosioni
Institution
Hospital Clinic-IDIBAPS
Country
ES