No pharmaceutical opinion available for this interaction.
Darunavir / ritonavir can induce the metabolism (UGT 1A4) and decrease the concentration of Lamotrigine.
2C9, 2C19, 2C8 (moderate), UGT (moderate)
3A4 (strong), 2D6 (moderate), 2B6 (probable)
UGT1A4 (65%), P-gp
UGT1A4 (light auto-induction)
Possible decrease of clinical efficacy.
An increase in dosage may be necessary.
Monitor for signs and symptoms of therapeutic failure.
Pharmacokinetic studies showed that the addition of a protease inhibitor (PI) combination containing ritonavir decreases lamotrigine plasma concentrations of about 32 to 55%. A lamotrigine dose of 200 mg BID with PI produces a concentration similar to lamotrigine 100 mg BID used alone.
See atazanavir/ritonavir + lamotrigine and lopinavir/ritonavir + lamotrigine.