What should a patient on Crestor (rosuvastatin) do if they experience muscle cramps all over their body?

Management of Muscle Cramps in a Patient on Crestor (Rosuvastatin)

Discontinue Crestor immediately and evaluate for rhabdomyolysis by checking creatine kinase (CK), creatinine, and urinalysis for myoglobinuria, as muscle cramps throughout the body represent a potentially serious adverse effect requiring prompt intervention. 1, 2

Immediate Actions

• Stop rosuvastatin now until symptoms can be fully evaluated, as the ACC/AHA guidelines mandate discontinuation for any unexplained muscle symptoms during statin therapy 1
• Check CK levels, serum creatinine, and urinalysis for myoglobinuria to rule out rhabdomyolysis, which can cause acute kidney injury and rare fatalities 1, 2
• Obtain thyroid-stimulating hormone (TSH), renal function tests, hepatic function tests, and vitamin D levels to identify conditions that increase muscle symptom risk 1, 3

Evaluation for Contributing Factors

The ACC/AHA guidelines emphasize evaluating for conditions that predispose to statin-related muscle symptoms 1:

• Hypothyroidism - common reversible cause 1, 4
• Vitamin D deficiency - frequently overlooked contributor 1, 3
• Renal or hepatic dysfunction - increases statin levels 1
• Rheumatologic disorders (polymyalgia rheumatica) or primary muscle diseases 1
• Drug interactions - check for cyclosporine, gemfibrozil, macrolide antibiotics, antifungal agents, or cytochrome P-450 inhibitors 3, 2

Rechallenge Strategy After Symptom Resolution

If muscle symptoms resolve and no contraindication exists, the ACC/AHA provides a structured approach 1:

• First option: Rechallenge with rosuvastatin at a lower dose (e.g., 5 mg instead of 10-20 mg) to establish causality 1, 3
• If symptoms recur: Switch to a different statin with lower myopathy risk, specifically pravastatin (hydrophilic with fewer drug interactions) 3
• Alternative: Use rosuvastatin on an alternate-day regimen at lower doses, as it has the longest half-life among statins and remains effective 3, 5
• Gradually titrate upward once a low dose is tolerated 1

If Symptoms Persist After 2 Months Off Statin

If muscle cramps do not completely resolve after 2 months without rosuvastatin, the symptoms are likely not statin-related, and you should pursue other diagnoses 1, 3. Once the alternative cause is treated, resume statin therapy at the original dose 1.

Alternative Lipid-Lowering Strategy

For patients who cannot tolerate any statin despite multiple attempts 3:

• Consider ezetimibe plus low-dose statin combination therapy 3
• Use the lowest effective statin dose that provides cardiovascular benefit 3, 4
• Monitor muscle symptoms at baseline, 6-12 weeks after starting therapy, and at each follow-up visit 3

Critical Safety Considerations

The FDA label warns that rosuvastatin may cause myopathy and rhabdomyolysis, with risk factors including age ≥65 years, uncontrolled hypothyroidism, renal impairment, and higher dosages 2. The 40 mg dose carries significantly higher myopathy risk than lower doses 3, 2. Patients must be instructed to promptly report any unexplained muscle pain, tenderness, or weakness, particularly if accompanied by malaise or fever 2.