Why does Buspar (buspirone) help with shivering related to anxiety?

Mechanism of Buspirone's Anti-Shivering Effects

Buspirone helps reduce shivering by modulating the hypothalamic thermostat through its action as a 5-HT1A receptor partial agonist, which can lower the shivering threshold by 2-3°C when used in combination with other medications. 1

Pharmacological Mechanism

Buspirone works through a unique mechanism compared to traditional anti-anxiety medications:

• Acts primarily as a serotonin 5-HT1A receptor partial agonist 2, 3
• Has moderate affinity for brain D2-dopamine receptors 4
• Does not act on GABA receptors, unlike benzodiazepines 4, 2
• Lacks the sedative, muscle relaxant, and anticonvulsant properties of benzodiazepines 5

Anti-Shivering Application

Buspirone is specifically used in shivering management during targeted temperature management (TTM) protocols:

• Administered at 30 mg every 8 hours as a preventative anti-shivering agent 1
• Most effective when used in combination therapy with other medications 1
• When combined with meperidine, can reduce the shivering threshold to as low as 33°C 1
• Used as part of a multimodal approach to shivering management 1

Clinical Effectiveness

The European Heart Journal guidelines (2023) specifically recommend buspirone as part of anti-shivering protocols:

1. It can be used preventatively rather than reactively 1
2. Works synergistically with other anti-shivering agents 1
3. Particularly effective in combination with opioid analgesics like meperidine 1

Dosing and Administration

For anti-shivering purposes:

• Dose: 30 mg every 8 hours 1
• Can be used alongside non-pharmacological measures like skin counterwarming 1
• Often incorporated into institutional protocols for shivering management 1

Limitations and Precautions

When using buspirone for shivering control:

• May lower seizure threshold - caution in patients with seizure history 1
• Has synergistic effects with other medications - monitor for additive effects 1
• Takes 1-2 weeks for full anxiolytic effect, though anti-shivering effects may occur sooner 5
• Requires continuous monitoring in patients receiving targeted temperature management 1

Clinical Algorithm for Anti-Shivering Management

1. Start with non-pharmacological measures (skin counterwarming, especially of extremities)
2. Add pharmacological agents in a stepwise approach:
   • Begin with acetaminophen and magnesium sulfate as non-sedating options
   • Add buspirone 30 mg every 8 hours as a preventative measure
   • Consider adding meperidine for synergistic effect if needed
   • Reserve neuromuscular blockade for refractory shivering 1

Buspirone represents an important component of modern shivering management protocols, particularly valuable because it can help reduce shivering without the heavy sedation associated with other agents.