[Direct mechanism of action in toxic myopathies]

Artemisinin-Based Combination Therapy Synergized with Medicinal Plants to Induce Musculotoxic Effects

Introduction

Multivisceral, neurological, hepatic, and renal damage has been witnessed following the use of artemisinin-based combination therapy (ACT) and herbal medicine. These multiple organ damages make us think of muscle damage. The objective was to study the myotoxicity of the combination of ACTs with medicinal plants.

Materials and Methods

Muscle cells (RD cells) were brought into contact with preparations of antimalarial drugs and/or antimalarial herbs. The following drugs were used: artesunate 100 mg/amodiaquine 270 mg (ASAQ) and artemether 80 mg/lumefantrine 480 mg (AL); plant Sida acuta (PSA) and plant Enantia polycarpa (PEP) at 10 µg/ml. After 5 days of incubation, the cells were counted by using a hemocytometer with trypan blue solution.

Results

Artesunate/amodiaquine caused a significant drop in the number of muscle cells, compared to the control, between D2 and D4 (p < 0.001). There was also a significant difference between the control and artemether/lumefantrine between D2 (p < 0.01) and D4 (p < 0.001) and between the control and the Sida acuta plant, on D2 (p < 0.001), D4 (p < 0.001), and D5 (p < 0.05). In tubes treated with ASAQ and Sida acuta, cell mortality was over 30%. Finally, statistically significant cell destruction in the tubes treated with the combination of antimalarial drugs and traditional plants compared to those of the control was observed from D2 (p < 0.001).

Conclusion

Artemisinin-based combination therapy remains effective and well tolerated. But its combination with medicinal plants induced myotoxic effects. This toxicity would appear to be of the additive type. Further studies should be able to better elucidate the mechanism of this toxicity.

Side Effects of Chloroquine and Hydroxychloroquine on Skeletal Muscle: a Narrative Review

Purpose of Review

Concerning adverse neuromuscular effects, there are quite a few reports about the incidence and prevalence of chloroquine (CQ) and hydroxychloroquine (HCQ) myopathy. Given the above, I decided to explore the relationships of these drugs with skeletal muscle in an attempt to clarify how they affect the muscle now and in the future, as millions of people are using CQ and HCQ.

Recent Findings

The literature review identified 28 publications about CQ/HCQ myopathy, totaling 56 patients, from 1963 to 2020. A compilation of all patients was carried out by computing demographic features, clinical aspects, laboratory exams, and clinical evolution. All articles but two represented a large series about incidence and prevalence of the myopathy. Fifty-nine percent used QC, mean daily dose was 393 mg per day, and mean duration of treatment was 37 months. The predominant underlying diseases were rheumatoid arthritis (42.8%) and lupus erythematosus (26.8%). Respiratory distress was present in 12.5% in patients with proximal muscle weakness (87.2%). Dysphagia and cervical and axial weakness were observed in a smaller percentage. Creatine kinase was elevated in 60.7%, and EMG showed a myopathic pattern in 54%. Muscle biopsy showed a vacuolar pattern in 53.7%, and curvilinear bodies (CB) were the predominant ultrastructural finding (86.8%). After drug withdrawal, 85.4% of patients improved, and 12.7% died from other causes than myopathy.

Summary

CQ and HCQ myopathy has been known for a long time, but the incidence is low, being described only with long-term use. The use of these drugs for a short period has not been reported, although a prolonged elimination half-life of these drugs actually exists.