Abstract and Introduction
Abstract
A 66-year-old man with diabetes and hypertension using statin was admitted to the hospital with progressive myalgia. He had been on rosuvastatin for five months. After beginning the use of phosphodiesterase-5 inhibitors, he presented with severe muscle pain and maintained penile erection. Several days after interruption of therapy, muscle pain and penile erection disappeared. This case demonstrates the interaction of sildenafil with rosuvastatin might result in myopathy.
Introduction
Hyperlipidemia and dyslipidemia constitute a vascular risk factor having a considerable impact on erectile function. Furthermore, the role of endothelial dysfunction in the pathophysiology of both erectile dysfunction (ED) and dyslipidemia emphasizes the importance of comanaging these conditions. Drugs that have been developed for vascular diseases and/or found to have beneficial endothelial effects may be helpful in the management of ED. A variety of medications have mechanisms of action that involve the endothelium such as statins, angiotensin-converting enzyme inhibitors (ACEI), angiotensin receptor blockers (ARB), certain beta blockers, some oral hypoglycemics, and the phosphodiesterase-5 inhibitors (PDE5i). Some of these drugs have been found to improve penile erection, although an endothelium dependent mechanism has not been conclusively demonstrated in all studies. Specialty statins are widely used in the treatment and prevention of atherosclerotic disease. The benefits of statins are well documented; however, side effects such as cases of myopathy are reported too. Statin-induced myopathy is now understood to be a heterogeneous condition that may be due to mechanisms of the drug itself; interactions with other drugs; or genetic, metabolic, and immunological vulnerabilities in individual patients. In some cases, statins may unmask latent conditions (eg, asymptomatic baseline myopathy) that predispose patients to muscle toxicity. The phosphodiesterase-5 inhibitors (PDE5i) sildenafil, vardenafil, and tadalafil are considered first-line therapy for the treatment of patients with erectile dysfunction (ED). The main adverse effects of phosphodiesterase-5 inhibitors, which are generally transient and rated as mild or moderate in severity, are dyspepsia, headache, and sometimes myalgia. In addition to the classical pro-erectile-effect, clinical findings have suggested that they can also influence vascular tone in pulmonary, coronary, and other vascular tissues, as well as improve symptoms associated with benign prostatic hyperplasia. Therefore, considering the hypothetical widespread application of PDE5i, the potential for drug-drug interactions emerges as a relevant factor in determining the safety profile of PDE5i.