{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T00:28:07Z","timestamp":1780446487514,"version":"3.54.1"},"reference-count":42,"publisher":"American Veterinary Medical Association (AVMA)","issue":"8","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["ajvr"],"published-print":{"date-parts":[[2017,8]]},"abstract":"<jats:title>Abstract<\/jats:title>\n<jats:p><jats:bold>OBJECTIVE<\/jats:bold> To assess the possible impact of medetomidine on concentrations of alfaxalone in plasma, when coadministered as a constant rate infusion (CRI) to dogs, and to determine the possible impact of medetomidine on the cardiopulmonary effects of alfaxalone during CRI.<\/jats:p>\n<jats:p><jats:bold>ANIMALS<\/jats:bold> 8 healthy adult Beagles.<\/jats:p>\n<jats:p><jats:bold>PROCEDURES<\/jats:bold> 3 treatments were administered in a randomized crossover design as follows: 1 = saline (0.9% NaCl) solution injection, followed in 10 minutes by induction of anesthesia with alfaxalone (loading dose, 2.4 mg\/kg; CRI, 3.6 mg\/kg\/h, for 60 minutes); 2 = medetomidine premedication (loading dose, 4.0 \u03bcg\/kg; CRI, 4.0 \u03bcg\/kg\/h), followed by alfaxalone (as in treatment 1); and, 3 = medetomidine (as in treatment 2) and MK-467 (loading dose, 150 \u03bcg\/kg; CRI, 120 \u03bcg\/kg\/h), followed by alfaxalone (as in treatment 1). The peripherally acting \u03b1<jats:sub>2<\/jats:sub>-adrenoceptor antagonist MK-467 was used to distinguish between the peripheral and central effects of medetomidine. Drugs were administered IV via cephalic catheters, and there was a minimum of 14 days between treatments. Cardiopulmonary parameters were measured for 70 minutes, and jugular venous blood samples were collected until 130 minutes after premedication. Drug concentrations in plasma were analyzed with liquid chromatography\u2013tandem mass spectrometry.<\/jats:p>\n<jats:p><jats:bold>RESULTS<\/jats:bold> The characteristic cardiovascular effects of medetomidine, such as bradycardia, hypertension, and reduction in cardiac index, were obtunded by MK-467. The concentrations of alfaxalone in plasma were significantly increased in the presence of medetomidine, indicative of impaired drug distribution and clearance. This was counteracted by MK-467.<\/jats:p>\n<jats:p><jats:bold>CONCLUSIONS AND CLINICAL RELEVANCE<\/jats:bold> The alteration in alfaxalone clearance when coadministered with medetomidine may be attributed to the systemic vasoconstrictive and bradycardic effects of the \u03b1<jats:sub>2<\/jats:sub>-adrenoceptor agonist. This could be clinically important because the use of \u03b1<jats:sub>2<\/jats:sub>-adrenoceptor agonists may increase the risk of adverse effects if standard doses of alfaxalone are used.<\/jats:p>","DOI":"10.2460\/ajvr.78.8.956","type":"journal-article","created":{"date-parts":[[2017,7,24]],"date-time":"2017-07-24T19:36:38Z","timestamp":1500924998000},"page":"956-964","source":"Crossref","is-referenced-by-count":18,"title":["Effects of the \u03b12-adrenoceptor agonist medetomidine on the distribution and clearance of alfaxalone during coadministration by constant rate infusion in dogs"],"prefix":"10.2460","volume":"78","author":[{"given":"Rachel C.","family":"Bennett","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kati M.","family":"Salla","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marja R.","family":"Raekallio","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mika","family":"Scheinin","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Outi M.","family":"Vainio","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1272","reference":[{"key":"ref1","series-title":"Anesthesiology","doi-asserted-by":"publisher","first-page":"488","DOI":"10.1097\/00000542-199209000-00014","article-title":"Modification of GABA-mediated inhibition by various injectable anesthetics","volume":"77","author":"Albertson","year":"1992"},{"key":"ref2","series-title":"Anesthesiology","doi-asserted-by":"publisher","first-page":"572","DOI":"10.1097\/00000542-199603000-00013","article-title":"Preemptive analgesic effects of steroid anesthesia with alphaxalone in the rat formalin 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