Atazanavir / 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 Atazanavir / ritonavir.

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

Atazanavir / ritonavir

Pharmacodynamic effects

Possible decrease of clinical efficacy.

Recommendations

Monitor for signs and symptoms of therapeutic failure.

An increase in dosage may be necessary.

Should not be administered without low-dose ritonavir or cobicistat.

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

Atazanavir plasma level

CD4+

Viral load HIV

Pharmacokinetic parameters

Comment

Reference
  • 1382
    Atazanavir (Reyataz), Bristol-Myers Squibb, Quebec, Canada, 26 octobre 2018.