Rhabdomyolysis induced by co-administration of fluvastatin and colchicine

Colchicine-Induced Acute Myopathy: Case Study From Saudi Arabia

Colchicine-induced myopathy has been described in patients with chronic renal failure and patients who are using a concomitant drug like a statin. However, pure myopathy caused by colchicine has never been reported in Saudi Arabia. A 64-year-old patient received colchicine for his gout arthritis disease and developed upper and lower limb weakness. He had a proximal weakness, and his muscle enzymes were very high. Furthermore, the needle electromyography (EMG) examination showed abundant fibrillations, myotonic discharges, and myopathic motor units. Two weeks after colchicine cessation, his weakness improved dramatically with normalization of creatine kinase (CK) and disappearance of myotonic discharges in the repeated EMG. This is the first case in Saudi Arabia that showed colchicine-induced myositis. The local clinicians' community needs to be aware of this rare side effect, as clinical suspicion is the most important diagnostic clue and the only effective treatment is the termination of colchicine.

Colchicine Myopathy: A Case Series Including Muscle MRI and ABCB1 Polymorphism Data

Colchicine is a medication most commonly used in the treatment of gout and familial mediterannean fever. A rare complication of therapy is toxicity causing proximal myopathy and polyneuropathy. Colchicine myopathy has been associated with the coadministration of other medications with colchicine, such as statins or tacrolimus, and is more common in patients with renal impairment. Otherwise, it is unclear which patients are at greatest risk of developing this adverse drug reaction. ABCB1 is important to the metabolism of colchicine, so we speculated that it was possible that colchicine myopathy patients may have a particular genotype that is associated with this side effect. We describe two cases of colchicine myopathy which occurred with co-administration of rosuvastatin. From one case, we present the first published data on muscle MRI in this condition. We additionally present an analysis of four genetic polymorphisms in ABCB1 and transcript levels in muscle tissue, and demonstrate the descriptive finding of reduced ABCB1 transcript levels in the colchicine myopathy patients.

Side Effects and Interactions of the Xanthine Oxidase Inhibitor Febuxostat

The paper addresses the safety of febuxostat and summarizes reports on side effects and interactions of febuxostat published by the cut-off date (last day of literature search) of 20 March 2018. Publications on side effects and the interactions of febuxostat were considered. Information concerning the occurrence of side effects and interactions in association with the treatment with febuxostat was collected and summarized in the review. The incidence of severe side effects was much less frequent than mild side effects (1.2–3.8% to 20.1–38.7%). The rate and range of febuxostat side effects are low at doses of up to 120 mg and only increase with a daily dose of over 120 mg. The publications reveal no age-dependent increase in side effects for febuxostat. In patients with impaired renal function, no increase in adverse events is described with a dose of up to 120 mg of febuxostat per day. Patients with impaired liver function had no elevated risk for severe side effects. A known allopurinol intolerance increases the risk of skin reactions during treatment with febuxostat by a factor of 3.6. No correlation between treatment with febuxostat and agranulocytosis has been confirmed. Possible interactions with very few medications (principally azathioprine) are known for febuxostat. Febuxostat is well tolerated and a modern and safe alternative to allopurinol therapy.

Characterization of Statin-Associated Myopathy Case Reports in Thailand Using the Health Product Vigilance Center Database

BACKGROUND

HMG-CoA reductase inhibitors [statins], a widely prescribed cholesterol-lowering therapy, are associated with muscle-related adverse events. While characteristics of such events are well documented in Western countries, little data exists for the Thai population.

OBJECTIVE

The aim of this study was to determine the characteristics of patients, type and dosing of statin, and to identify patterns of drug use that may be associated with such adverse events using the national pharmacovigilance database known as Thai Vigibase.

METHOD

Muscle-related adverse events involving statins in the Thai Vigibase from 1996 to December 2009 were identified. For each report, the following information was extracted: patient demographics, co-morbidities, detailed information of adverse event, detailed information of suspected drug, treatment and outcome, as well as causality assessment and quality of reports. Descriptive statistics were performed for all study variables.

RESULTS

A total of 198 cases of statin-associated muscle-related adverse events were identified. Mean age was 61.4 ± 12.4 years of age and 59.6% were female. Simvastatin, atorvastatin, rosuvastatin and cerivastatin were implicated as the suspected drug in 163 (82.3%), 24 (12.1%), 10 (5.1%) and 1 (0.5%) cases, respectively. Rhabdomyolysis accounted for 55.6% of all muscle-related adverse events. Drug interactions known to enhance such toxicity of statins were identified in 40.9% of the total set of reports. Similar to studies from Western countries, fibrates, HIV protease inhibitors, non-dihydropyridine calcium channel blockers, azole antifungals and macrolides were commonly found in such cases. Interestingly, colchicine has been identified as the second most common drug interaction in our database. Case fatality rates were 0.9, 1.6 and 16.7%, when there were 0, 1 and ≥2 interacting drugs, respectively.

CONCLUSIONS

Characteristics of muscle-related adverse events with statins in the Thai population showed some similarities and differences compared with Western countries. Such similarities included advanced age, female sex, certain co-morbidities and drug interactions. While the majority of interacting drugs are well known, a big proportion of cases of statin-colchicine interaction attributed to long-term use of colchicine in Thailand was noted and should be further investigated. Based on these results, an attempt to avoid dangerous and well-known drug interactions among statin users should be implemented nationwide.

Colchicine-Induced Acute Neuromyopathy in a Patient Using Concomitant Fluconazole: Case Report and Literature Review

A 54-year-old woman presented at the emergency department after experiencing lower limb weakness and bilateral ankle pain for 2 days. She had a history of type 2 diabetes mellitus, diabetes mellitus nephropathy with chronic kidney disease, and chronic gouty arthritis. She had received 0.6 mg colchicine orally once or twice daily for 8 months. Four days prior to her emergency department visit, she was discharged from our nephrology ward, where she had been admitted because of a urinary tract infection. During hospitalization, she was treated with intravenous cefazolin for 7 days. Because of persistent symptoms, we performed repeated urinalysis, which revealed the presence of yeast. She was diagnosed with fungal cystitis, and was administered a 7-day course of once-daily oral fluconazole (100 mg). On day 5 of the course, she was discharged and asked to continue taking oral colchicine (0.6 mg, twice daily), as well as fluconazole for the full 7-day course. Neurological examination revealed marked symmetrical weakness (Medical Research Council grade 4/5). Her sensation and coordination were intact. Initial laboratory investigation revealed hyperkalemia (6.2 mmol/L), and blood urea nitrogen, serum creatinine, and creatine kinase levels of 181, 11.16 mg/dL, and 803 U/L respectively. Her liver function tests showed elevated alanine aminotransferase levels (112 U/L). Electromyographic results were consistent with colchicine neuromyopathy. Ten days after treatment cessation, muscle enzyme levels normalized and weakness gradually disappeared. We used the Drug Interaction Probability Scale to evaluate our patient’s case. A score of 5 was calculated, indicating that the drug–drug interaction was the probable cause of neuromuscular toxicity.

Effect of steady-state atorvastatin on the pharmacokinetics of a single dose of colchicine in healthy adults under fasted conditions

BACKGROUND AND OBJECTIVE

Colchicine is commonly prescribed for gout. While minimally metabolized by the cytochrome P450 (CYP) 3A4 isoenzyme, colchicine is a substrate for P-glycoprotein (P-gp). Atorvastatin is metabolized primarily by CYP3A4 and is a P-gp inhibitor. Patients with gout often have dyslipidemia; therefore, the potential for co-administration of atorvastatin and colchicine exists. The objective of this study was to determine the effect of oral atorvastatin on the pharmacokinetics of a single, oral dose of colchicine.

METHODS

Twenty-four healthy adult subjects were enrolled in this single-center, open-label, non-randomized, one-sequence, two-period drug-drug interaction study. On day 1, subjects received a single oral dose of colchicine 0.6 mg. After a 14-day washout, subjects received atorvastatin 40 mg once daily for 14 days followed by a single dose of colchicine 0.6 mg co-administered with atorvastatin 40 mg on day 28. Main outcome measures were colchicine maximum plasma concentration (C max), area under the plasma concentration-time curve (AUC) from time zero to the last measurable concentration (AUC last), and AUC from time zero to infinity (AUC∞), which were compared with and without concurrent atorvastatin.

RESULTS

Colchicine AUC last, AUC∞, and C max increased by 27, 24, and 31 %, respectively, when co-administered with atorvastatin. Corresponding 90 % confidence intervals around the ratios were outside the established no-effect 80-125 % interval.

CONCLUSION

Increased colchicine exposure was observed after a single dose of colchicine was administered with steady-state atorvastatin. Additional studies with multiple dosing of both drugs are needed to further determine the clinical implications of these results.