Rosuvastatin, widely known by the brand name Crestor, is a statin, or an HMG-CoA reductase inhibitor. This drug blocks the enzyme responsible for cholesterol production in the liver, effectively lowering low-density lipoprotein (LDL) cholesterol and triglycerides. While rosuvastatin is highly effective for managing high cholesterol and reducing cardiovascular risk, it is not without potential side effects. Understanding the range of possible reactions is important for patient safety and successful long-term adherence to the treatment plan.
Common and Mild Adverse Reactions
The majority of people who take rosuvastatin experience no side effects, or only reactions that are mild and often resolve as the body adjusts to the therapy. Among the most frequently reported issues are generalized aches and muscle pain. Headache is also a common complaint reported by patients beginning rosuvastatin treatment.
Gastrointestinal symptoms frequently occur, including mild nausea, abdominal discomfort, constipation, or diarrhea. Patients may also report generalized weakness or fatigue. These mild adverse reactions are generally manageable and usually do not require the medication to be stopped, though patients should discuss any persistent symptoms with their healthcare provider.
Recognizing Severe Musculoskeletal Complications
The most serious and well-recognized category of rosuvastatin side effects involves the skeletal muscles, presenting a spectrum of severity that requires careful monitoring. The mild aches mentioned above are known as myalgia and represent the least severe end of this spectrum. A more concerning reaction is myopathy, characterized by muscle pain or weakness accompanied by an elevation of muscle enzymes, specifically creatine kinase (CK), in the bloodstream.
The most severe, though rare, complication is rhabdomyolysis, a condition where rapid muscle cell breakdown occurs. This process releases muscle proteins, including myoglobin, into the circulation, which can subsequently damage the kidneys. Symptoms of rhabdomyolysis include severe, unexplained, and persistent muscle pain, tenderness, or weakness, often accompanied by a fever. A distinctive and concerning sign is dark, tea-colored urine, which indicates the presence of myoglobin being filtered by the kidneys.
The incidence of rhabdomyolysis is extremely low, but it can be potentially fatal if not treated immediately. Patients must contact a healthcare provider immediately if they develop severe muscle pain, muscle weakness, or dark urine. This is a medical emergency that necessitates prompt discontinuation of the drug and supportive medical management to prevent acute kidney injury.
Effects on Liver Function and Necessary Monitoring
Rosuvastatin, like other statins, has the potential to affect liver function, primarily by causing an elevation in liver enzymes known as transaminases (ALT and AST). This enzyme elevation is typically asymptomatic, mild, and transient. Monitoring is necessary.
Before starting rosuvastatin, a healthcare provider will typically order baseline Liver Function Tests (LFTs) to establish a starting point for monitoring. Follow-up LFTs are often performed when clinically indicated or if the patient reports symptoms suggestive of liver injury. If the enzyme levels increase significantly—specifically three times the upper limit of normal—the dosage may need to be reduced or the medication stopped, even without symptoms.
Clinically apparent liver injury is an exceedingly rare event, but patients should be aware of the signs that may indicate a more serious problem. These signs include:
- Jaundice (yellowing of the skin or eyes)
- Persistent fatigue
- Nausea
- Vomiting
- Loss of appetite
- Pain in the upper right quadrant of the abdomen
Acute liver failure has been reported in rare cases.
Factors That Increase Risk and Contraindications
Certain patient characteristics and co-administered medications can significantly increase the risk of experiencing adverse effects from rosuvastatin, particularly the muscle and liver complications. A higher daily dosage, such as the 40 mg strength, carries a greater risk of both muscle damage and transaminase elevation compared to lower doses. Advanced age, specifically being 65 years or older, is a risk factor for myopathy due to age-related changes in metabolism.
Individuals with pre-existing conditions like uncontrolled hypothyroidism or impaired kidney function are also at increased risk for muscle complications. Rosuvastatin is metabolized in a way that can be affected by other drugs, which increases the concentration of the statin in the blood and raises the risk of side effects. Co-administration with medications like gemfibrozil, a fibrate used for cholesterol, or the immunosuppressant cyclosporine, is generally not recommended due to a significantly elevated risk of myopathy and rhabdomyolysis.
Active liver disease, such as acute liver failure or decompensated cirrhosis, is considered an absolute contraindication. Rosuvastatin is also contraindicated during pregnancy and breastfeeding because it can potentially cause harm to the developing fetus or infant by interfering with cholesterol synthesis. Patients who consume substantial amounts of alcohol are also at a higher risk for hepatic injury while taking the medication.