title: Antinociceptive and side-effects of hydromorphone after subcutaneous administration in cats.
abstract: The subcutaneous (SC) route is often chosen for drug administration in cats because it is easier to perform than intravenous (IV) injection and is perceived as less painful than intramuscular (IM) injection. However, little is known of how the route of administration influences the pharmacodynamics of drugs. This study measured the changes in skin temperature and thermal threshold (TT) and recorded the side-effects after SC injection of 0.1mg/kg of hydromorphone in six cats. Time to peak TT was 105min. Skin temperature was elevated at 15min and between 45 and 360min. Five cats vomited and two exhibited marked dysphoria. Compared to previously published studies of IV and IM administration of hydromorphone, the SC route results in a slower onset of peak effect, a shorter duration of antinociception and is associated with more undesirable side-effects. As with IV and IM injections, SC administration of hydromorphone at 0.1mg/kg is associated with a significant elevation in skin temperature. Overall, the SC route appears to have the least utility.
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0136, USA. robertsons@vetmed.ufl.edu
authors.forename: Sheilah A
authors.initials: SA
authors.lastname: Robertson
authors.forename: Kirsten
authors.initials: K
authors.lastname: Wegner
authors.forename: Benedict Duncan X
authors.initials: BD
authors.lastname: Lascelles
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D000818:Animals; D002371:Cat Diseases / Q000139:chemically induced; D002415:Cats / Q000378:metabolism*; D005260:Female; D004091:Hydromorphone / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D007279:Injections, Subcutaneous / Q000662:veterinary; D008297:Male; D012798:Sialorrhea / Q000139:chemically induced / Q000662:veterinary; D012881:Skin Temperature / Q000187:drug effects*; D013997:Time Factors; D014839:Vomiting / Q000139:chemically induced / Q000662:veterinary
chemical_list: D000701:Analgesics, Opioid; D004091:Hydromorphone