Effectiveness of gabapentin in combination therapy for phenobarbital-responsive sialadenosis in a Toy Poodle

A 9-year-old Toy Poodle presented with sudden hypersalivation, vomiting, and retching unresponsive to symptomatic treatment. One month later, the mandibular salivary glands were enlarged and painful. Additional signs included weight loss, intermittent stiffness and tremors, and a fly-biting behavior, which is atypical for this disease. Magnetic resonance imaging revealed bilateral enlargement of the parotid and mandibular glands. Oral phenobarbital (PB) led to marked improvement, confirming phenobarbital-responsive sialadenosis. Residual hypersalivation and retching almost completely resolved within 24 hr after gabapentin (GBP) addition, with only mild hypersalivation (about 10% of the initial level) remaining. No recurrence was observed during a 3-year follow-up, during which PB (3.6 mg/kg administered orally twice daily [PO BID]) and GBP (15 mg/kg PO BID) were continued at the same doses.