Can Mounjaro (tirzepatide) cause muscle cramps or pain?

Muscle Cramps and Pain with Mounjaro (Tirzepatide)

Yes, Mounjaro (tirzepatide) can cause muscle cramps and pain, as evidenced by a recent case report of severe rhabdomyolysis requiring hospitalization in a patient taking tirzepatide for weight loss. 1

Mechanism and Evidence

• Tirzepatide is a novel dual glucose-dependent insulinotropic polypeptide (GIP) receptor and GLP-1 receptor agonist used for managing type 2 diabetes and weight loss 2
• A recent case report documented severe rhabdomyolysis (extreme muscle breakdown) in a 35-year-old female taking tirzepatide, with muscle biopsy revealing necrotizing myopathy 1
• Another study found that tirzepatide treatment resulted in skeletal muscle mass loss that constituted approximately 34% of total body weight loss in a patient 3

Risk Factors and Monitoring

• Patients taking tirzepatide should be monitored for symptoms of muscle pain, weakness, and dark urine which could indicate muscle breakdown 1
• Electrolyte abnormalities, particularly hypokalemia and hypomagnesemia, can exacerbate muscle cramps and should be monitored and corrected 4
• The risk of muscle-related side effects may be higher in patients with pre-existing muscle conditions or those taking other medications that affect muscle function 1

Management of Muscle Cramps Associated with Tirzepatide

If muscle cramps occur while taking Mounjaro, consider the following approach:

1. First-line interventions:

   • Rest and discontinue the activity that triggered the cramp 4
   • Stretching and massaging the affected muscles 4
   • Application of ice to the cramping muscle 4

2. If cramps persist or are severe:

   • Consider temporary dose reduction or discontinuation of tirzepatide if symptoms are severe 1
   • Baclofen (starting at 10 mg/day with weekly increases up to 30 mg/day) may be effective for severe cramps 5, 4
   • Ensure adequate hydration and electrolyte balance 4

3. For refractory cases:

   • Methocarbamol can be considered for skeletal muscle pain, though effects are nonspecific 5, 4
   • Human albumin (20-40 g/week) may be beneficial, particularly in patients with liver disease 5, 4

Important Considerations

• Muscle mass loss with tirzepatide appears to be proportional to weight loss (approximately 15% from initial value) 3
• If possible, body composition assessments should be obtained in patients on tirzepatide to monitor muscle mass changes 3
• In cases of severe muscle pain with elevated creatine kinase levels, tirzepatide should be discontinued and the patient should receive appropriate medical care including IV fluids 1

When to Seek Medical Attention

• Severe or persistent muscle pain
• Significant muscle weakness
• Dark urine (tea-colored)
• Signs of rhabdomyolysis, which requires immediate medical attention 1

While muscle cramps and pain are potential side effects of Mounjaro, the benefits of improved glycemic control and weight reduction may outweigh these risks for many patients. However, close monitoring and prompt management of muscle-related symptoms are essential.