Side Effect: Increased Muscle Breakdown (rhabdomyolysis)

What is Increased Muscle Breakdown (rhabdomyolysis)?

Increased muscle breakdown, known as rhabdomyolysis, is a condition in which damaged skeletal muscle tissue breaks down rapidly, releasing enzymes and other cellular contents into the bloodstream. This can lead to kidney damage, electrolyte imbalances, and other complications.

What does Increased Muscle Breakdown (rhabdomyolysis) look like?

Rhabdomyolysis can have a variety of symptoms, including:

• muscle pain
• weakness
• swelling
• dark urine

However, not all patients may experience all of these symptoms, and some patients may have no symptoms at all.

Who gets Increased Muscle Breakdown (rhabdomyolysis)?

Rhabdomyolysis can be caused by intense physical exertion, trauma, prolonged immobilization, seizures, and infections. Patients with cancer may receive cancer treatments that increase the risk of developing rhabdomyolysis. These medications include, but are not limited to:

• Alectinib (Alecensa®)
• Brigatinib (Alunbrig®)
• Cobimetinib (Cotellic®)
• Binimetinib (Mektovi®)
• Lurbinectedin (Zepzelca®)
• Trabectedin (Yondelis®)

How to prevent Increased Muscle Breakdown (rhabdomyolysis)

Preventing rhabdomyolysis involves monitoring for signs and symptoms and avoiding strenuous exercise and other activities that may exacerbate severe muscle damage.

Patients who are at risk for rhabdomyolysis may have a blood test called creatine phosphokinase (CPK, or CK) monitored as elevations in CPK are often seen during periods of increased muscle breakdown and can be an early indicator of rhabdomyolysis.

In general, working out and modest physical activity is good for your health and does not increase the risk of rhabdomyolysis. If concerned about how strenuous your work-out routine is, ask your doctor if it increases your risk of developing rhabdomyolysis.

How to treat Increased Muscle Breakdown (rhabdomyolysis)

Treatment of rhabdomyolysis largely involves managing complications such as acute kidney injury and electrolyte imbalances.

Treatment of kidney injury may include:

• intravenous hydration
• alkalinization of the urine
• in severe cases, dialysis.

Intravenous replacement of electrolytes is typically utilized to address any imbalances.

If there are concerns for rhabdomyolysis due to chemotherapy treatment, the offending agent is typically stopped. Once rhabdomyolysis has been effectively treated, the offending agent can be restarted in some cases at a lower dose, or it may need to be switched to an alternative therapy.