https://interactions.guidetherapeutiquevih.com/en/interaction-details?id=12611

Ritonavir

Phenobarbital

Not recommended association.

No pharmaceutical opinion available for this interaction.

Mechanism

Phenobarbital can induce the metabolism (CYP 3A4) and decrease the plasma concentration of Ritonavir.

Ritonavir can induce the metabolism (CYP 2C9 and CYP 2C19) and decrease the plasma concentration of Phenobarbital.

Ritonavir

Pharmacodynamic effects

Possible decrease of clinical efficacy.

Risk of a possible development of resistance to antiretroviral class.

Therefore, resulting in loss of therapeutic effect of associated IP.

Recommendations

Monitor for signs and symptoms of therapeutic failure.

Alternative solution(s)

–

Phenobarbital

Pharmacodynamic effects

Possible decrease of clinical efficacy.

Recommendations

Avoid if possible. Use an alternative or monitor patient closely.

Monitor for signs and symptoms of therapeutic failure.

Titrate dose based on patient response and tolerability.

Alternative solution(s)

As clinically indicated : brivaracetam, gabapentin, lacosamide, lamotrigine, levetiracetam, pregabalin, rufinamide, topiramate, vigabatrin, zonisamide.

Monitor

–

Tests

Phenobarbital

Associated PI plasma level

CD4+

Viral load HIV

Pharmacokinetic parameters

–

Comment

–

Reference
  • 2573
    Ritonavir (Norvir), Corporation AbbVie, Quebec, Canada, 5 juillet 2021.