An 85-year-old woman presented with an acute onset of generalised weakness and functional decline. The patient had a history of insulin-requiring diabetes, hypercholesterolaemia, hypertension, glaucoma and chronic kidney disease. She also had longstanding fungal keratitis (>60 days) which had been unsuccessfully treated with topical therapy.
The patient’s chronic conditions were managed with multiple medications, including simvastatin 20 mg daily. She had started oral voriconazole, 200 mg twice a day, 32 days before her admission.
The patient was observed in hospital for a few weeks. She was examined by two ophthalmology senior house officers and an infectious diseases physician before a general physician made the diagnosis of rhabdomyolysis.
Blood tests showed a creatine kinase of 23 200 U/L (normal range 34–145), aspartate transaminase 1030 U/L (<31), alanine transaminase 393 U/L (<34) and creatinine 255 micromol/L (<110). Sodium, potassium, prothrombin time and full blood count were normal. The rhabdomyolysis was suspected to be the result of a drug interaction between simvastatin and voriconazole.1 Both drugs were ceased on day 20 of the patient’s admission and her blood tests improved. Unfortunately, the woman’s clinical symptoms did not resolve and she died of respiratory failure secondary to respiratory muscle weakness 10 days after the concurrent therapy was stopped.
The interaction between voriconazole and simvastatin is not adequately described in commonly available references. The clinical significance of this interaction may be increased when individual patient factors are taken into account. Clinicians should be vigilant for this interaction and the need to consider individual risk factors when reviewing patients. A focus on tasks and processes in hospitals runs the risk of removing the patient as the focus of care.
- Ballantyne CM, Corsini A, Davidson MH, Holdaas H, Jacobson TA, Leitersdorf E, et al. Risk for myopathy with statin therapy in high-risk patients. Arch Intern Med 2003;163:553-64.
- Australian Medicines Handbook. Table B-3 Drugs and CYP enzymes. In: Australian Medicines Handbook. Adelaide: AMH Pty Ltd; 2011. p 939.
- iPharmacy Version 5.6 [software]. Sydney: iSOFT; 2012.