Second-Degree Type 2 Atrioventricular Block Requiring Permanent Cardiac Pacing in Patients on CDK4/6 Inhibitors: Report of Two Cases.

Introduction: A wide spectrum of cardiovascular (CV) toxicity is associated with anticancer treatment, and nearly all chemotherapeutic agents can elicit CV toxicity. Inhibitors of cyclin-dependent kinases 4/6 (CDK4/6Is) have become standard of care in the treatment of hormone receptor-positive, human epidermal growth factor receptor 2-negative metastatic breast cancer (MBC). CV side effects are uncommon with CDK4/6Is and only include QT prolongation, with a low incidence rate.

Sildenafil and bosentan plasma concentrations in a human immunodeficiency virus- infected patient with pulmonary arterial hypertension treated with ritonavir-boosted protease inhibitor.

Sildenafil and bosentan are increasingly used for the treatment of pulmonary arterial hypertension (PAH) in HIV-infected patients. However, concerns exist about pharmacokinetic interactions among sildenafil, bosentan and antiretroviral drugs, including protease inhibitors (PI). We describe here the case of an HIV-infected patient with PAH, who was co-administered bosentan 125 mg twice daily and sildenafil 40 mg three times per day, together with a ritonavir-boosted PI-based antiretroviral therapy; plasma levels of bosentan, sildenafil, N-desmethylsildenafil, and PI were measured.

Bosentan and sildenafil in the treatment of HIV-associated pulmonary hypertension.

We present the case of an HIV/HCV-coinfected patient with HIV-related pulmonary hypertension (HRPH) who experienced a good clinical and functional response to bosentan, with a subsequent switch to oral sildenafil due to increased transaminase levels. Bosentan resulted less handy in this case, probably due to both side effects and co-morbidities.