What is causing the patient's shaking and nausea after receiving intravenous (IV) daptomycin?

Daptomycin-Induced Adverse Reactions: Shaking and Nausea

The patient's shaking and nausea after receiving IV daptomycin is most likely due to an infusion-related reaction, which can be prevented by administering daptomycin over a longer infusion time rather than rapid IV push.

Mechanism of Daptomycin-Related Adverse Reactions

Daptomycin is a cyclic lipopeptide antibiotic used to treat various Gram-positive infections. When administered intravenously, it can cause several adverse reactions:

1. Infusion-related reactions:

   • Rapid administration (2-minute IV push) can cause flushing, warmth, redness, and systemic symptoms including shaking and nausea 1
   • Similar to "red man syndrome" seen with vancomycin but through a different mechanism

2. Myotoxicity:

   • Primary concern with daptomycin is myopathy and rhabdomyolysis 2
   • Requires weekly monitoring of creatine phosphokinase (CPK) 3

3. Gastrointestinal effects:

   • Nausea and vomiting are common adverse reactions, particularly in pediatric patients 2

Management Approach

Immediate Management

1. Slow the infusion rate:

   • Change from rapid IV push to standard infusion over 30-40 minutes 1
   • Evidence shows that the same dose administered over a longer period significantly reduces infusion reactions

2. Symptomatic treatment:

   • Antihistamines (e.g., diphenhydramine 25-50mg) may provide limited relief for flushing symptoms 1
   • Anti-emetics for nausea (ondansetron 4-8mg IV or granisetron 1mg IV) 4

Prevention of Future Reactions

1. Standard infusion protocol:

   • Administer daptomycin over 30 minutes for doses up to 6 mg/kg 2
   • For higher doses (>6 mg/kg), consider 60-minute infusions 2

2. Monitoring:

   • Weekly monitoring of CPK, complete blood count, renal function, and liver enzymes 3
   • More frequent monitoring in patients with risk factors for myopathy

Clinical Pearls and Pitfalls

• Do not confuse with anaphylactic reactions, which would present with more severe symptoms including respiratory distress and hypotension
• Rechallenge is possible with a slower infusion rate - patients who experience reactions with rapid administration often tolerate the same dose when given over 30-40 minutes 1
• Avoid rapid IV push administration of daptomycin, especially in outpatient settings where monitoring may be limited
• Consider dose adjustment in obese patients, as higher serum concentrations may increase risk of adverse effects including neurotoxicity 5
• Do not discontinue therapy unnecessarily - daptomycin remains an important option for treating resistant Gram-positive infections, and most infusion reactions can be managed by adjusting administration technique

By slowing the infusion rate and providing appropriate symptomatic management, most patients can continue to receive daptomycin therapy safely and effectively.