title: Pharmacokinetics and milk secretion of gabapentin and meloxicam co-administered orally in Holstein-Friesian cows.
abstract: Management of neuropathic pain in dairy cattle could be achieved by combination therapy of gabapentin, a GABA analog and meloxicam, an nonsteroidal anti-inflammatory drug. This study was designed to determine specifically the depletion of these drugs into milk. Six animals received meloxicam at 1 mg/kg and gabapentin at 10 mg/kg, while another group (n=6) received meloxicam at 1 mg/kg and gabapentin at 20 mg/kg. Plasma and milk drug concentrations were determined over 7 days postadministration by HPLC/MS followed by noncompartmental pharmacokinetic analyses. The mean (±SD) plasma C(max) and T(max) for meloxicam (2.89±0.48 μg/mL and 11.33±4.12 h) were not much different from gabapentin at 10 mg/kg (2.87±0.2 μg/mL and 8±0 h). The mean (±SD) milk C(max) for meloxicam (0.41±80.16 μg/mL) was comparable to gabapentin at 10 mg/kg (0.63±0.13 μg/mL and 12±6.69 h). The mean plasma and milk C(max) for gabapentin at 20 mg/kg p.o. were almost double the values at 10 mg/kg. The mean (±SD) milk to plasma ratio for meloxicam (0.14±0.04) was lower than for gabapentin (0.23±0.06). The results of this study suggest that milk from treated cows will have low drug residue concentration soon after plasma drug concentrations have fallen below effective levels.
authors.affiliation: Department of Clinical Sciences, Kansas State University College of Veterinary Medicine, Manhattan, KS 66506, USA.
authors.forename: P R
authors.initials: PR
authors.lastname: Malreddy
authors.forename: J F
authors.initials: JF
authors.lastname: Coetzee
authors.forename: B
authors.initials: B
authors.lastname: Kukanich
authors.forename: R
authors.initials: R
authors.lastname: Gehring
mesh_terms: D000284:Administration, Oral; D000588:Amines / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics*; D000700:Analgesics / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics*; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics*; D002417:Cattle; D003509:Cyclohexanecarboxylic Acids / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics*; D004359:Drug Therapy, Combination / Q000662:veterinary; D005260:Female; D000077206:Gabapentin; D000077239:Meloxicam; D008892:Milk / Q000737:chemistry*; D013843:Thiazines / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics*; D013844:Thiazoles / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics*; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics*
chemical_list: D000588:Amines; D000700:Analgesics; D000894:Anti-Inflammatory Agents, Non-Steroidal; D003509:Cyclohexanecarboxylic Acids; D013843:Thiazines; D013844:Thiazoles; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin; D000077239:Meloxicam