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- Author or Editor: Elizabeth M. Hardie x
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Abstract
Objective
To evaluate the disposition of fentanyl after IV and transdermal administrations. The hypothesis was that transdermal administration of fentanyl would result in a measurable plasma opioid concentration.
Design
Each dog received 2 treatments in a randomized, crossover design.
Animals
6 clinically normal Beagles.
Procedure
2 treatments consisting of IV fentanyl (50 μg/kg of body weight) and transdermal fentanyl (50 μg/h) administrations. Plasma fentanyl concentrations were measured at fixed times, and pharmacokinetic values were calculated.
Results
Intravenous pharmacokinetics of fentanyl was similar to those previously described in dogs and provided the distribution and clearance data necessary to calculate the rate of absorption of the transdermally administered opioid. The transdermal fentanyl patch produced average steady-state concentrations of 1.6 ng/ml. The actual rate of delivery of transdermal fentanyl was 35.7 (range, 13.7 to 49.8) μg/h, which represented 71.48% (range, 27.45 to 99.56%) of the theoretical rate of delivery. The mean elimination half-life of fentanyl after patch removal was 1.39 hours.
Conclusions
Transdermally administered fentanyl resulted in fairly constant plasma concentrations, in the range generally considered to be analgesic, from 24 to 72 hours after application of the patch. The rate of drug delivery was less than expected, and there was substantial individual variation.
Clinical Relevance
Transdermally administered fentanyl has the potential to be a clinically useful analgesic regimen in dogs, and further evaluation of its analgesic actions and potential side effects is warranted. (Am J Vet Res 1996; 57:715–719)
Objective—
To evaluate vestibulovaginal stenosis in dogs.
Design—
Retrospective study.
Animals—
18 dogs with vestibulovaginal stenosis diagnosed between January 1987 and June 1995.
Procedure—
Signalment, results of physical examination, and diagnostic testing, treatment, and outcome were analyzed.
Results—
Mean age at initial examination was 4.6 years. Problems reported by the owners included signs of chronic urinary tract infection (6 dogs), urinary incontinence (4), failure to mate (4), signs of chronic vaginitis (2), and inappropriate urination (1). One dog did not have evidence of a clinical problem. Vestibulovaginal stenosis was detected by means of digital vaginal examination (18/18 dogs), vaginoscopy (17/17 dogs), and positive-contrast vaginography (9/10 dogs). Bacteria were isolated from the urine of 11 of 15 dogs. Twelve of 18 dogs were treated. Manual dilation (4 dogs) and T-shaped vaginoplasty (4) were less successful than vaginectomy (2) or resection of the stenotic area (3). Four of 6 dogs with signs of recurrent urinary tract infection underwent surgical correction, and none of these dogs subsequently had urinary tract infection. Three of 4 dogs with urinary incontinence responded to medical or surgical treatment for sphincter incompetence or for ectopic ureters.
Clinical Implications—
Surgical correction of vestibulovaginal stenosis is indicated in dogs that have mating difficulties or signs of recurrent urinary tract infection or chronic vaginitis, but stenosis is probably an incidental finding in most dogs with urinary incontinence. Vaginectomy and vaginal resection and anastomosis are the preferred surgical options. (J Am Vet Med Assoc 1996;209:1889–1893)
Abstract
Objective—To compare pharmacokinetic and pharmacodynamic characteristics of fentanyl citrate after IV or transdermal administration in cats.
Animals—6 healthy adult cats with a mean weight of 3.78 kg.
Procedure—Each cat was given fentanyl IV (25 mg/cat; mean ± SD dosage, 7.19 ± 1.17 mg/kg of body weight) and via a transdermal patch (25 µg of fentanyl/h). Plasma concentrations of fentanyl were measured by use of radioimmunoassay. Pharmacokinetic analyses of plasma drug concentrations were conducted, using an automated curvestripping process followed by nonlinear, leastsquares regression. Transdermal delivery of drug was calculated by use of IV pharmacokinetic data.
Results—Plasma concentrations of fentanyl given IV decreased rapidly (mean elimination half-life, 2.35 ± 0.57 hours). Mean ± SEM calculated rate of transdermal delivery of fentanyl was 8.48 ± 1.7 mg/h (< 36% of the theoretical 25 mg/h). Median steadystate concentration of fentanyl 12 to 100 hours after application of the transdermal patch was 1.58 ng/ml. Plasma concentrations of fentanyl < 1.0 ng/ml were detected in 4 of 6 cats 12 hours after patch application, 5 of 6 cats 18 and 24 hours after application, and 6 of 6 cats 36 hours after application.
Conclusions and Clinical Relevance—In cats, transdermal administration provides sustained plasma concentrations of fentanyl citrate throughout a 5- day period. Variation of plasma drug concentrations with transdermal absorption for each cat was pronounced. Transdermal administration of fentanyl has potential for use in cats for long-term control of pain after surgery or chronic pain associated with cancer. (Am J Vet Res 2000;61:672–677)
Abstract
Objective—To determine prevalence of radiographic evidence of degenerative joint disease (DJD) in geriatric cats.
Design—Retrospective study.
Population—100 cats > 12 years of age.
Procedure—One investigator reviewed radiographs and for each articulation (or group of articulations) that was visible assigned a grade of severity (0, 1, 2, 3) for DJD. Another investigator reviewed medical records and recorded signalment, environment, previous disease, diseases evident at time of radiography, FeLV vaccination and infection status, feline immunodeficiency virus serologic status, serum creatinine concentration, serum globulin concentration, and any other important findings. Associations between DJD of grade 2 or 3 and variables recorded from the medical record were determined.
Results—Radiographic evidence of DJD was evident in 90% of cats. Neurologic disease was associated with lesions in the lumbosacral portion of the vertebral column. Severe lesions were found in 17% of the elbow joints, but an underlying cause was not determined.
Conclusions and Clinical Relevance—Degenerative joint disease was detected radiographically in most geriatric cats and may be an overlooked cause of clinical disease. Clinicians should be alert to the possibility that DJD is associated with neurologic signs. (J Am Vet Med Assoc 2002;220:628–632)
Abstract
Objective—To document the signalment; history; clinical signs; clinicopathologic, diagnostic imaging, and surgical findings; perioperative complications; and long-term clinical results of ameroid ring constrictor (ARC) placement on single extrahepatic portosystemic shunts (PSS) in cats.
Design—Retrospective study.
Animals—23 cats treated with an ARC on a single extrahepatic PSS.
Procedure—An ARC was placed surgically around the PSS. Portal pressure was measured prior to ARC placement, with complete temporary PSS occlusion, and after ARC placement. Cats were scheduled for recheck transcolonic portal scintigraphy 8 to 10 weeks after surgery. Follow-up information was obtained by telephone interview with the owners.
Results—An ARC was successfully placed in 22 of 23 cats. Intraoperative complications, consisting of PSS hemorrhage, occurred in 2 cats. Mean (± SD) portal pressure (n = 15) was 6.7 ± 2.9 mm Hg before PSS manipulation, 18.6 ± 7.7 mm Hg with complete temporary PSS occlusion, and 6.9 ± 2.7 mm Hg after ARC placement. Postoperative complications developed in 77% (17 of 22) of cats after ARC placement, and included central blindness, hyperthermia, frantic behavior, and generalized motor seizures. Perioperative mortality rate was 4.3% (1 of 23). Persistent shunting was identified in 8 of 14 cats. Overall, 75% (15 of 20) of cats had an excellent longterm outcome.
Conclusions and Clinical Relevance—Placement of an ARC on single extrahepatic PSS in cats resulted in low surgical complication and perioperative mortality rates, but most cats did have substantial postoperative complications. Persistent shunting was common, although many cats with persistent shunting were clinically normal. (J Am Vet Med Assoc 2002;220: 1341–1347)
Objective
To determine whether maintenance energy requirement (MER) to maintain stable body weight (BW) is substantially lower for spayed female cats than for sexually intact female cats and to assess whether an equation commonly used to estimate MER would accurately predict caloric need in spayed cats.
Design
Prospective study.
Animals
10 spayed and 5 sham-operated young adult female cats.
Procedure
During an acclimatization period, initial daily food allowance was determined by estimating MER as 1.4 × (30 × BW + 70), then adjusted weekly to maintain BW within 200 g of baseline. Ovariohysterectomy (OHE) or sham laparotomy was performed at week 7, and the study was continued for 15 additional weeks (period 1). To correct for a presumptive effect of continued musculoskeletal growth that resulted in some cats becoming unacceptably thin during period 1, the study was repeated over an additional 10 weeks (period 2), using a new estimate of MER calculated from BW measured after reestablishing normal body condition.
Results
Substantial restriction in food allowance was necessary to prevent BW gain in the OHE group during both periods. Caloric intake of spayed cats in dietary balance was significantly lower than that of control cats at the end of each study period. Sexually intact cats appeared to self-regulate food intake, whereas spayed cats tended to eat all food available to them. Significant differences were not detected between OHE and control groups in observations of physical activity before or after surgery. The equation used to predict caloric needs overestimated the apparent MER for spayed and sexually intact cats.
Clinical Implications
Ad libitum feeding of spayed cats may be inadvisable, and careful monitoring of food allowance, relative to body condition, is suggested to prevent excessive weight gain. (J Am Vet Med Assoc 1996;209:1572–1581)
SUMMARY
Cisplatin (90 mg/m2) was administered in a 5-minute bolus iv infusion to dogs at 8 am (n = 6) or 4 pm (n = 6). Blood and urine samples were collected over a 4-hour period for statistical moment pharmacokinetic analysis. Mean urinary excretion rate of total platinum was increased, whereas mean plasma residence time of ultrafilterable platinum was decreased, in the group treated at 4 pm (pm group), compared with those treated at 8 am (am group). Over a 2-week postinfusion-monitoring period, both groups of dogs developed decreases in creatinine clearance, urine/serum osmolality ratio (UOsm/SOsm), specific gravity, and increase in bun, serum creatinine concentration, urine γ-glutamyltranspeptidase/urine creatinine ratio (UGGT/UCr), fractional excretion of magnesium, and fractional excretion of phosphate. Urine specific gravity and UOsm/SOsm were significantly decreased, whereas UGGT/UCr and bun were significantly increased in the am group, compared with the pm group. The time of administration had a significant effect on the pharmacokinetics of cisplatin, which resulted in significant differences in cisplatin-induced renal toxicosis.
