No pharmaceutical opinion available for this interaction.
Lopinavir / ritonavir may possibly inhibit the metabolism (CYP 3A4 and 2D6) and consequently increase the concentration of Trazodone.
Possible additive effects for the prolongation of the QT interval .
3A4 (major), 13 identified metabolites, 5 of these metabolites are linked to the metabolism of ritonavir, transporters: MRP1, MRP2, OATP1A2, OATP1B1, P-gp
2C19 (strong), 1A2, 2C9 (moderate) UGT (moderate)
3A4 and 2D6 (strong), transporters: BCRP, MRP2, OATP1A2, OATP1B1, OATP1B3, OATP2B1, P-gp
3A4 (major) 2D6 (minor)/ Metabolized into m-chlorophenylpiperazine.
Possible increase of adverse effects.
Increased risk of QT interval prolongation.
If antiretroviral therapy is going on, start with a small dose and gradually increase depending on efficacy and safety.
If patient already on trazodone and antiretroviral therapy is started, reduce the dose by 50% and gradually increase depending on efficacy and safety.
In patients already being treated with this combination and tolerating it, if deemed appropriate, keep actual treatment and exercise close monitoring of adverse effects.
Monitor closely. Avoid association in patients at high risk of QT prolongation.
Trazodone toxicity: dizziness, fatigue, sweating, orthostatic hypotension, syncope, priapism.
Anticholinergic adverse effects: xerostomia, constipation, urinary retention, sedation, drowsiness, blurred vision, akathisia, convulsions, tachycardia, hypotension, etc.
Ref #1515 : When co-administering a single dose of trazodone with ritonavir 200 mg BID an increase was observed in trazodone AUC and Cmax of 140% and 34%, respectively. Cases of patients showing symptoms as nausea, dizziness, fatigue, performance issues, hypotension and syncope have been reported.
Ref #2377 : According to the product monograph, post-marketing reports of QT prolongation and torsade de pointes were reported even though no causal link with lopinavir/ritonavir could be established. The use of lopinavir/ritonavir in patients taking other QT prolonging drugs should be avoided.