Elvitegravir / Cobicistat

Tadalafil (Cialis)

Modification of dose and/or administration time necessary.

No pharmaceutical opinion available for this interaction.

Mechanism

Elvitegravir / Cobicistat can inhibit the metabolism (CYP 3A4) and increase the plasma concentration of Tadalafil (Cialis).

Elvitegravir / Cobicistat

Pharmacodynamic effects

Recommendations

Alternative solution(s)

Tadalafil (Cialis)

Pharmacodynamic effects

Possible increase of adverse effects.

Recommendations

Use as needed: start at 10 mg every two days and if needed increase to 20 mg, maximum of 3 times a week.

If the 10 mg dose is not tolerated, tadalafil treatment should be stopped.

Once-daily use: usual dose of 5 mg QD could be used. If intolerance, reduce the dose to 2.5 mg QD.

Monitor closely clinical efficacy and appearance of adverse effects.

Give extra caution to patients with hepatic or renal insufficiency, or older than 65 years.

Alternative solution(s)

Monitor

Tadalafil toxicity: hypotension, tachycardia, headache, dizziness, flushing, visual changes (difficulty distinguishing blue and green) and syncope.

Tests

Pharmacokinetic parameters

Comment

Ritonavir 200 mg BID (a powerful inhibitor of CYP 3A4) increases the AUC of tadalafil 124%. See ritonavir and tadalafil (Cialis).

Caution: Liver impairment and kidney failure (Clcr 31-50 ml/min: increases twice AUC)and age > 65 years old can increase the concentration of tadalafil. See tadalafil (Adcirca).

Reference
  • 1383
    Tadalafil (Cialis), Eli Lilly, Ontario, Canada, 22 novembre 2016.
  • 2570
    Elvitegravir/cobicistat/emtricitabine/tenofovir (Stribild), Gilead, Ontario, Canada, 17 septembre 2018.
  • 2914
    Loulergue P, Gaillard R, Mir O. Interaction involving tadalafil and CYP3A4 inhibition by ritonavir. Scand J Infect Dis 2011 Mar; 43(3): 239-40.
  • 2376
    Tadalafil (Adcirca), Eli Lilly, Ontario, Canada, 22 novembre 2016.
  • 3281
    Elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide(Genvoya), Gilead, Ontario, Canada, 17 septembre 2018.