The Effect of Transdermal Delivery of Fentanyl on Activity in Growing Pigs

Autor: Nyman G, Jensen-Waern M, Augustsson H, Malavasi LM
Jazyk: angličtina
Rok vydání: 2005
Předmět:
Zdroj: Acta Veterinaria Scandinavica, Vol 46, Iss 3, Pp 149-157 (2005)
Druh dokumentu: article
ISSN: 1751-0147
DOI: 10.1186/1751-0147-46-149
Popis: Abstract Recently, decreased activity levels have been observed in pigs treated postoperatively with transdermal delivery of fentanyl (TD-fentanyl) after isoflurane anaesthesia. Whether the change in behaviour is related to opioid-induced sedation or to insufficient pain relief remains to be investigated. This study was therefore undertaken to evaluate the effect of TD-fentanyl 50 μg h-1 on the activity level with and without isoflurane anaesthesia. Eight pigs (25.4 ± 5.2 kg) were submitted to a cross-over study and given two treatments; 1) fentanyl patch applied after 30 minutes of anaesthesia (treatment A/F) and 2) fentanyl patch without anaesthesia (treatment F). The pigs' behaviour was observed from a video recording instantaneously every 10 minutes for 24 h before treatments and up to 72 h after the patch attachment. Venous blood samples were taken 1, 6, 12, 24, 48 and 72 h after the patch application. The behaviour recordings showed that TD-fentanyl did not produce sedation in any pig. No differences were found between the two treatments in activity level, weight gain or serum fentanyl concentration. This concentration measured after 24 h was 0.27 ± 0.11 ng ml-1 and 0.47 ± 0.40 ng ml-1 in the A/F and F group, respectively. In conclusion, transdermal delivery of 50 μg h-1 fentanyl did not cause inactivity in growing pigs. However, the large variations in serum fentanyl concentration indicate that drug absorption from transdermal patches is unpredictable and sometimes deficient.
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