Myopathy from the combination of simvastatin and amiodarone

Reporting of Drug-Induced Myopathies Associated with the Combination of Statins and Daptomycin: A Disproportionality Analysis Using the US Food and Drug Administration Adverse Event Reporting System

BACKGROUND

Myopathy is one of the most common adverse reactions of daptomycin and statins. We aimed to evaluate the muscular toxicity of the combination therapy of daptomycin and statins in a large pharmacovigilance database.

METHODS

This was a retrospective disproportionality analysis based on real-world data. All cases reported between the first quarter of 2004 and the fourth quarter of 2022 where daptomycin and statins were reported were gathered from the US Food and Drug Administration Adverse Event Reporting System (FAERS) database. Disproportionality analyses were conducted by estimating the proportional reporting ratios (PRRs), reporting odds ratio (ROR), and information component (IC).

RESULTS

A total of 971,861 eligible cases were collected from the FAERS database. Data analysis showed that rosuvastatin (ROR: 124.39, 95% CI: 87.35-178.47), atorvastatin (ROR: 68.53, 95% CI: 51.93-90.43), and simvastatin (ROR: 94.83, 95% CI: 71.12-126.46) combined with daptomycin increased the reporting frequency of myopathy. Moreover, myopathy was reported more frequently with the 3-drug combination (ROR: 598.01, 95% CI: 231.81-1542.71). For rhabdomyolysis, the frequency of reports also increased when daptomycin was combined with rosuvastatin (ROR: 156.34, 95% CI: 96.21-254.05), simvastatin (ROR: 72.65, 95% CI: 47.36-111.44), and atorvastatin (ROR: 66.31, 95% CI: 44.06-99.81).

CONCLUSIONS

The combination of daptomycin and statins increased the association of myopathy and rhabdomyolysis, especially with rosuvastatin, simvastatin, and atorvastatin.

Late and Severe Myopathy in a Patient With Glycogenosis VII Worsened by Cyclosporine and Amiodarone

Glycogenosis VII (GSD VII) is a rare autosomal recessive glycogen storage disorder caused by mutations in the PFKM gene encoding the phosphofructokinase (PFK) enzyme. A classical form with exercise intolerance, contractures, and myoglobinuria, a severe multisystem infantile form, an hemolytic variant and a late-onset form usually presenting with muscle pain and mild fixed proximal weakness have been reported. We describe a 65-year-old man affected by muscle PFK deficiency who, since the age of 33, presented with exercise intolerance and myoglobinuria. Muscle biopsy showed a vacuolar myopathy with glycogen storage. The biochemical assay of PFK-M showed very low residual activity (6%). Genetic analysis of PFKM gene evidenced the presence of the heterozygote c.1817A>C (p.Asp543Ala) and c.488 G>A (p.Arg100Gln) pathogenic mutations. In his fifth decade, he started cyclosporine after liver transplantation for hepatocellular carcinoma and, then, amiodarone because of atrial fibrillation. In the following years, he developed a progressive and severe muscle weakness, mainly involving lower limbs, up to a loss of independent walking. Muscle MRI showed adipose substitution of both anterior and posterior thigh muscles with selective sparing of the medial compartment. Marked signs of adipose substitution were also documented in the legs with a selective replacement of gemelli and peroneus muscles. The temporal relationship between the patient's clinical worsening and chronic treatment with cyclosporine and amiodarone suggests an additive toxic damage by these two potentially myotoxic drugs determining such an unusually severe phenotype, also confirmed by muscle MRI findings.

The causes of drug-induced muscle toxicity

PURPOSE OF REVIEW

Clinically identified myopathies are frequently a consequence of medication toxicities. However, recognizing drug-induced myopathies is sometimes difficult. Developing a greater understanding of the underlying mechanisms of drug-induced muscle toxicity will promote enhanced awareness and recognition, and improved management of these syndromes.

RECENT FINDINGS

The adverse impact of certain drugs on muscle metabolism, muscle cell atrophy, and myocyte apoptosis is increasingly clear. Glucocorticoids impair glucose handling and directly promote protein catabolism. Statins impair mitochondrial function and alter intracellular signaling proteins, which can lead to myocyte apoptosis. Alternatively, statins can induce an autoimmune necrotizing myositis. Several medications impair autophagy, thus limiting access to the needed glycogen stores.

SUMMARY

This review provides an overview of the main underlying mechanisms of drug-induced myopathies. These myopathies will most often be related to a drug's ability to alter metabolism and protein balance, induce necrosis, or impair autophagy.

Does Simvastatin Cause More Myotoxicity Compared with Other Statins?

Objective:

To review the literature regarding statins and myotoxicity and evaluate these data to determine whether incidence rates are higher with simvastatin.

Data Sources:

Literature was identified from a search of MEDLINE (1966–August 2009) and International Pharmaceutical Abstracts (1970–August 2009), as well as references of selected articles. Key search terms included the names of individual statins, rhabdomyolysis, myopathy, myalgia, myotoxicity, statins, and drug interactions.

Study Selection and Data Extraction:

All English-language articles discussing statin-related myotoxicity and relevant drug interactions that involved human subjects were examined.

Data Synthesis:

Simvastatin is a commonly prescribed, moderately potent statin. Recent evidence suggests that the risk of severe muscle toxicity with simvastatin may be higher than that with other statins, particularly when used in combination with cytochrome P450 isoenzyme inhibitors. However, the lack of direct comparative clinical trials assessing the risk of myotoxicity among the statins in equivalent doses precludes definitive conclusions. Data sources examining low-to-mode rate doses of simvastatin suggest that myotoxicity with this agent is infrequent, with rates similar to those seen with other statins. Conversely, findings from clinical trials using the maximum daily dose (80 mg) and a clinical trials database of varying doses of simvastatin suggest a possible increase in rates of myotoxicity with the 80-mg dose compared with lower doses and a higher incidence rate when compared with maximum doses of other statins.

Conclusions:

Overall, the rates of severe myotoxicity with all statins are low, especially with low-to-moderate doses. However, recent trials for those using simvastatin 80 mg daily suggest a higher incidence of myotoxicity compared with maximum approved doses of other statins. Practitioners should be aware of these possible risks and individualize therapy to limit myotoxicity.

Simvastatin and Amiodarone: Emergence of a Potentially Toxic Interaction

This continuing feature updates readers on recent developments in cardiovascular pharmacotherapy. Cardiovascular disease remains the number 1 killer in the United States, and more clinical outcome trials have been conducted in cardiology than in any other field of medicine. Given this rapidly expanding knowledge base, if pharmacists stay current with developments in drug therapy, they can have a significant impact on prevention and treatment.