What is the CHILL protocol and how do I dose trazodone, gabapentin, and acepromazine in combination?

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The CHILL protocol — formally the GMA protocol — combines oral gabapentin (20–25 mg/kg PO), oral melatonin (3 mg for dogs under 10 kg; 5 mg for dogs over 10 kg), and oral-transmucosal (OTM) acepromazine (0.05 mg/kg), all administered by the owner prior to hospital arrival.1 The protocol reduces stress scores in over 70% of anxious and aggressive dogs when administered as a client-administered preappointment protocol.1 Gabapentin and melatonin act synergistically, and acepromazine functions as a reliable tranquilizer that decreases struggle and fear during examination — reducing the need for fear-inducing restraint — rather than as a standalone anxiolytic.1 Acepromazine in this protocol is administered OTM, not orally or parenterally, at 0.05 mg/kg.1 Acepromazine has minimal to no anxiolytic effect on its own and should not be used as a sole agent for fear or phobic states.1 Although acepromazine has been associated with increased noise sensitivity and disinhibition of aggression in other contexts, no dogs in the GMA protocol study exhibited increased noise sensitivity or worsened aggression.1 Melatonin dosing is weight-based by threshold rather than mg/kg: 3 mg PO for dogs under 10 kg and 5 mg PO for dogs over 10 kg.1 Vital parameters after melatonin administration remain within physiological ranges, supporting its safety in dogs.1 | Drug | Dose | Route | Key Caveat | |---|---|---|---| | Gabapentin | 20–25 mg/kg | PO | Synergistic with melatonin and acepromazine | | Melatonin | 3 mg (<10 kg) / 5 mg (>10 kg) | PO | Not a per-kg calculation above 10 kg threshold | | Acepromazine | 0.05 mg/kg | OTM | Not anxiolytic as sole agent; tranquilizer only | Would you like guidance on timing — specifically how far before the appointment each drug should be administered?