Myotoxicity of statins: Mechanism of action.

Statins are effective drugs to reduce cardiovascular events secondary to dyslipidemia; however, they cause frequent undesirable side effects. The incidence of statin-induced myotoxicity (SIM) is presented by 7 to 29% of patients, depending upon the report. SIM may develop in presence of abnormally high concentrations of statins in the myocyte and/or in presence of muscular conditions that may predispose to SIM. High concentrations of statins in the myocyte may occur whenever the activity of liver influx membrane transporters, namely OATP1B1, of drug metabolizing enzymes, and of liver and muscular efflux transporters, MDR1 and BCRP, is reduced. In the muscle, conditions that may predispose to SIM include mitochondrial damage with disruption of the mitochondrial respiratory chain and decreased production of ATP, increase of ROS, and leak of cytochrome c and Ca2+. In the sarcoplasma, statins activate MAPK and diminish the RhoA/AKT/mTOR/PGC-1α pathway. All these effects contribute to activate apoptosis, proteolysis, and muscle remodeling. Moreover, in the sarcoplasma, statins can reduce the resting chloride channel conductance, as well as lactate efflux. These changes will be responsible of fatigue, cramps, myalgia and elevation of serum CK. To date, besides avoiding drug-drug interactions and alcohol consumption, and correcting hypothyroidism, two strategies could be useful to prevent/diminish SIM, e.g. gradual dose titration with statins less prone to produce SIM, and high supplements of vitamin D in subjects with low plasma concentrations of 25(OH) D3.

Effectiveness and tolerability of oral administration of low-dose salmon oil to HIV patients with HAART-associated dyslipidemia.

PURPOSE: To assess the effectiveness of low-dose salmon oil for the treatment of highly active antiretroviral therapy (HAART)-induced dyslipidemia in HIV-infected patients. METHOD: Randomized, open-label, parallel and crossover, multicenter study. Patients received 1 g salmon oil tid for 24 weeks (SO-24) or no additional treatment for 12 weeks and salmon oil for weeks 12 to 24 (CT-SO). The primary outcome measure was the change in triglyceride (TG) levels. RESULTS: Fifty-eight patients completed the study (26 in SO-24; 32 in CT-SO). After 12 weeks, the SO-24 group experienced a mean TG reduction of 1.1 mmol/L, compared to an increase of 0.3 mmol/L for the CT-SO group (p = .040). When CT-SO patients were crossed over to salmon oil treatment, mean TG decreased by 0.7 mmol/L (p = .052). Concomitant use of fibrates, statins, or both were reported by 16 (27.6%), 10 (17.2%), and 8 (13.8%), respectively. Multivariate analysis showed that salmon oil produced a significant decrease in TG levels independent of other lipid-lowering medications (p = .022). There were 26 predominately mild treatment-emergent (antiretroviral or salmon oil) nonserious adverse events reported by 22 (33.3%) patients. CONCLUSION: Low-dose salmon oil (3 g/day) is effective and well-tolerated in reducing TG levels in HIV-infected patients receiving HAART.