Drug-drug Interactions

There are no specifically mentioned DDIs in the Endocrine Society Clinical Practice Guidelines or the AACE Hypogonadism Guidelines regarding ARV drugs and treatment for hypogonadism in male patients.



Phosphodiesterase (PDE)-5 inhibitors prescribed for erectile dysfunction are metabolized via the same enzyme (CYP3A4) in the liver as many ARV therapies. Therefore, co-administration may lead to elevated levels of PDE-5 inhibitor in the blood,1,2 so dose reduction/modification of the PDE-5 inhibitor may be required.

  • Potential DDIs may occur if sildenafil is co-administered with PIs or NNRTIs.3
     

Physicians should be aware of potential DDIs when planning to use specific medication combinations. There are a number of online resources for assessment of DDIs: one such tool is the HIV drug interactions website.

References

  1. Merry C, Barry MG, Ryan M, et al. Interaction of sildenafil and indinavir when co-administered to HIV-positive patients. AIDS. 1999;13:101–107.
  2. Muirhead GJ, Wulff MB, Fielding A, et al. Pharmacokinetic interactions between sildenafil and saquinavir / ritonavir. Br J Clin Pharmacol. 2000;50:99–107.
  3. HIV drug interactions. The Liverpool HIV Pharmacology Group (LHPG) Accessed 13 February 2012.