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PubMed2001

Cardiopulmonary assessment of medetomidine, ketamine, and butorphanol anesthesia in captive Thomson's gazelles (Gazella thomsoni).

This investigation evaluated the cardiopulmonary effects of medetomidine, ketamine, and butorphanol anesthesia in captive juvenile Thomson's gazelles (Gazella thomsoni). Butorphanol was incorporated to reduce the dose of medetomidine necessary for immobilization and minimize medetomidine-induced adverse cardiovascular side effects. Medetomidine 40.1 +/- 3.6 microg/kg, ketamine 4.9 +/- 0.6 mg/kg, and butorphanol 0.40 +/- 0.04 mg/kg were administered intramuscularly by hand injection to nine gazelles. Times to initial effect and recumbency were within 8 min postinjection. Cardiopulmonary status was monitored every 5 min by measuring heart rate, respiratory rate, indirect blood pressure, end-tidal CO2, and indirect oxygen-hemoglobin saturation by pulse oximetry. Venous blood gases were collected every 15 min postinjection. Oxygen saturations less than 90% in three gazelles suggested hypoxemia. Subsequent immobilized gazelles were supplemented with intranasal oxygen throughout the anesthetic period. Sustained bradycardia (<60 beats per minute, as compared with anesthetized domestic calves, sheep, and goats) was noted in eight of nine gazelles. Heart and respiratory rates and rectal temperatures decreased slightly, whereas systolic, mean, and diastolic blood pressure values were consistent over the anesthetic period. Mild elevations in end tidal CO2 and PCO2 suggested hypoventilation. Local lidocaine blocks were necessary to perform castrations in all seven of the gazelles undergoing the procedure. Return to sternal recumbency occurred within 7 min and return to standing occurred within 12 min after reversal with atipamezole (0.2 +/- 0.03 mg/kg) and naloxone (0.02 +/- 0.001 mg/kg). Medetomidine, ketamine, and butorphanol can be used to safely anesthetize Thomson's gazelles for routine, noninvasive procedures. More invasive procedures, such as castration, can be readily performed with the additional use of local anesthetics.

Analgesics, Opioid↗

PubMed2002

Effects of morphine, butorphanol, buprenorphine, and U50488H on the minimum alveolar concentration of isoflurane in cats.

OBJECTIVE: To determine whether opioids with varying interactions at receptors induce a reduction in minimum alveolar concentration (MAC) of isoflurane in cats. ANIMALS: 12 healthy, female, spayed cats. PROCEDURE: Cats were anesthetized with isoflurane and instrumented to allow collection of arterial blood and measurement of arterial blood pressure. Each drug was studied separately, and for each drug cats were randomly allocated to receive 2 doses. The drugs studied were morphine (0.1 or 1.0 mg/kg), butorphanol (0.08 or 0.8 mg/kg), buprenorphine (0.005 and 0.05 mg/kg), and U50488H (0.02 and 0.2 mg/kg). All drugs were diluted in 5 ml of saline (0.9% NaCl) solution and infused IV for 5 minutes. The MAC of isoflurane was determined in triplicate, the drug administered, and the MAC of isoflurane redetermined for a period of 3 hours. RESULTS: All drugs had a significant effect on MAC over time. With morphine only, the effect on MAC over time was different between doses. The greatest mean (+/- SD) reductions in MAC of isoflurane in response to morphine, butorphanol, buprenorphine, and U50488H administration were 28 +/- 9, 19 +/- 3, 14 +/- 7, and 11 +/- 7%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Morphine (1.0 mg/kg) and butorphanol (0.08 and 0.8 mg/kg) induced significant reductions in MAC of isoflurane that were considered clinically important. Although significant, reductions in MAC of isoflurane induced by morphine (0.1 mg/kg), buprenorphine (0.005 and 0.05 mg/kg), and U50488H (0.02 and 0.2 mg/kg) were not considered clinically relevant because they fell within the error of the measurement technique. Administration of morphine or butorphanol decreases the need for potent inhalant anesthetics in cats and could potentially be beneficial in combination with inhalants.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗

PubMed2002

Effects of treatment with oxytocin, xylazine butorphanol, guaifenesin, acepromazine, and detomidine on esophageal manometric pressure in conscious horses.

OBJECTIVE: To compare effects of oxytocin, acepromazine maleate, xylazine hydrochloride-butorphanol tartrate, guaifenesin, and detomidine hydrochloride on esophageal manometric pressure in horses. ANIMALS: 8 healthy adult horses. PROCEDURE: A nasogastric tube, modified with 3 polyethylene tubes that exited at the postpharyngeal area, thoracic inlet, and distal portion of the esophagus, was fitted for each horse. Amplitude, duration, and rate of propagation of pressure waveforms induced by swallows were measured at 5, 10, 20, 30, and 40 minutes after administration of oxytocin, detomidine, acepromazine, xylazine-butorphanol, guaifenesin, or saline (0.9% NaCI) solution. Number of spontaneous swallows, spontaneous events (contractions that occurred in the absence of a swallow stimulus), and high-pressure events (sustained increases in baseline pressure of > 10 mm Hg) were compared before and after drug adminision. RESULTS: At 5 minutes after administration, detomidine increased waveform amplitude and decreased waveform duration at the thoracic inlet. At 10 minutes after administration, detomidine increased waveform duration at the thoracic inlet. Acepromazine administration increased the number of spontaneous events at the thoracic inlet and distal portion of the esophagus. Acepromazine and detomidine administration increased the number of high-pressure events at the thoracic inlet. Guaifenesin administration increased the number of spontaneous events at the thoracic inlet. Xylazine-butorphanol, detomidine, acepromazine, and guaifenesin administration decreased the number of spontaneous swallows. CONCLUSIONS AND CLINICAL RELEVANCE: Detomidine, acepromazine, and a combination of xylazine butorphanol had the greatest effect on esophageal motility when evaluated manometrically. Reduction in spontaneous swallowing and changes in normal, coordinated peristaltic activity are the most clinically relevant effects.

Acepromazine↗

PubMed2003

Effect of carprofen, etodolac, meloxicam, or butorphanol in dogs with induced acute synovitis.

OBJECTIVE: To compare the analgesic and anti-inflammatory effect of single doses of carprofen, etodolac, meloxicam, and butorphanol in dogs with induced acute synovitis (acute pain model) via kinetic gait analysis and orthopedic evaluation and examine measurement of serum C-reactive protein (CRP) concentration as an indicator of treatment efficacy. ANIMALS: 12 Beagles and 6 additional Beagles that were used only in serum CRP analyses. PROCEDURE: Acute synovitis was induced in right stifle joints of dogs via intra-articular injection of monosodium urate solution. Treatments included butorphanol (0.2 mg/kg, i.v.), carprofen (4 mg/kg, PO), etodolac (17 mg/kg, PO), or meloxicam (0.2 mg/kg, PO); control dogs received no treatment. The procedure was repeated (3-week intervals) until all dogs received all treatments including control treatment. Lameness was assessed on a biomechanical force platform and via orthopedic evaluations of the stifle joints; blood was collected to monitor serum CRP concentration. RESULTS: Compared with control dogs, treated dogs had significantly different vertical ground reaction forces and weight-bearing scores. Greatest improvement in lameness was observed in carprofen-treated dogs. Etodolac had the fastest onset of action. Compared with butorphanol treatment, only carprofen and etodolac were associated with significantly lower pain scores. An increase in serum CRP concentration was detected after intra-articular injection in all dogs; this change was similar among groups. CONCLUSIONS AND CLINICAL RELEVANCE: Carprofen, etodolac, and meloxicam had greater efficacy than butorphanol in relief of acute pain. Carprofen was most effective overall. In this acute pain model, serum CRP analysis was not useful to assess drug efficacy.

Acute Disease↗

PubMed2003

Minimum alveolar concentration of isoflurane in green iguanas and the effect of butorphanol on minimum alveolar concentration.

OBJECTIVE: To determine minimum alveolar concentration (MAC) of isoflurane in green iguanas and effects of butorphanol on MAC. DESIGN: Prospective randomized trial. ANIMALS: 10 healthy mature iguanas. PROCEDURE: in each iguana, MAC was measured 3 times: twice after induction of anesthesia with isoflurane and once after induction of anesthesia with isoflurane and IM administration of butorphanol (1 mg/kg [0.45 mg/lb]). A blood sample was collected from the tail vein for blood-gas analysis at the beginning and end of the anesthetic period. The MAC was determined with a standard bracketing technique; an electrical current was used as the supramaximal stimulus. Animals were artificially ventilated with a ventilator set to deliver a tidal volume of 30 mL/kg (14 mL/lb) at a rate of 4 breaths/min. RESULTS: Mean +/- SD MAC values during the 3 trials (2 without and 1 with butorphanol) were 2.0 +/- 0.6, 2.1 +/- 0.6, and 1.7 +/- 0.7%, respectively, which were not significantly different from each other. Heart rate and end-tidal partial pressure of CO2 were also not significantly different among the 3 trials. Mean +/- SD heart rate was 48 +/- 10 beats/min; mean end-tidal partial pressure of CO2 was 22 +/- 10 mm Hg. There were no significant differences in blood-gas values for samples obtained at the beginning versus the end of the anesthetic period. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the MAC of isoflurane in green iguanas is 2.1% and that butorphanol does not have any significant isoflurane-sparing effects.

Analgesics, Opioid↗

PubMed1991

Dose-response of intravenous butorphanol to increase visceral nociceptive threshold in dogs.

This study was designed to determine the effective analgesic dose of butorphanol administered intravenously to obtund visceral nociception, as well as to determine duration of this effect. Additionally, cardiovascular changes and sedative effects were defined. Eight healthy dogs were each given five doses of butorphanol (0.025, 0.05, 0.1, 0.2, and 0.4 mg/kg) plus a sterile water placebo intravenously in a randomized blinded format. Antinociception was assessed using an inflatable Silastic balloon inserted into the colon. Blood pressures and pulse rates were measured with a noninvasive monitor. The greatest efficacy and longest duration of antinociception were produced by 0.4 mg/kg of butorphanol, with a duration of 38 +/- 9 min. Arterial blood pressure and pulse rate did not vary at antinociceptive doses. Mild sedation was observed at all doses, which generally lasted longer than the antinociceptive effects. These data suggest that butorphanol can be given alone intravenously to provide visceral antinociception lasting 30-45 min without significant side effects.

Animals↗

PubMed2000

The magnitude and duration of the analgesic effect of morphine, butorphanol, and buprenorphine in rats and mice.

This study was designed to determine the magnitude and duration of the analgesic effect of three commonly used opioids: buprenorphine (0.5 mg/kg for rats; 2.0 mg/kg for mice), butorphanol (2.0 mg/kg for rats; 5.0 mg/kg for mice), and morphine (10 mg/kg for rats and mice). We used two standard tests, the hot plate and tail flick assays, to measure opioid analgesia in 62 male, 200 to 300 g Sprague-Dawley rats and 61 male, 25 to 35 g ICR mice. We obtained five baseline measurements then administered the drugs subcutaneously. Morphine gave the highest analgesic effect and was intermediate in duration (2 to 3 h in rats and mice) of analgesia. Butorphanol provided the lowest level of and shortest (1 to 2 h in rats and mice) analgesia. Buprenorphine had an intermediate analgesic effect and the longest duration (6 to 8 h in rats and 3 to 5 h in mice). In light of our results, we recommend the use of morphine (with frequent redosing) for severe pain, butorphanol for mild pain of short duration, and buprenorphine for mild to moderate pain of increased duration. The dosing intervals suggested by our study are 2 to 3 h for morphine in both rats and mice, 1 to 2 h for butorphanol in both rats and mice; and 6 to 8 h in rats and 3 to 5 h in mice for buprenorphine.

Analgesia↗

PubMed2001

Enadoline and butorphanol: evaluation of kappa-agonists on cocaine pharmacodynamics and cocaine self-administration in humans.

Preclinical studies have demonstrated that kappa-opioid agonists can attenuate the neurochemical and behavioral effects of cocaine that are related to its reinforcing efficacy, suggesting that kappa-agonists may serve as pharmacotherapies for cocaine dependence. This 8-week inpatient study examined the ability of enadoline, a selective and high-efficacy kappa-agonist, and butorphanol, a mixed agonist with intermediate efficacy at both mu- and kappa-receptors, to reduce the direct pharmacodynamic effects and self-administration of intravenous cocaine in humans (n = 8). Acute doses of intramuscular enadoline (20, 40, and 80 microg/kg), butorphanol (1.5, 3, and 6 mg/70 kg) and placebo were examined separately as pretreatments during each of three test sessions with cocaine in a constrained random order. A cocaine dose-effect session (0, 20, and 40 mg cocaine i.v., 1 h apart) examined direct pharmacodynamic interactions on subjective and physiological indices; self-administration sessions examined choice behavior for cocaine (40 mg i.v. for six trials) versus money 1) in the presence of a sample cocaine dose with money choices presented in ascending value, and 2) in the absence of a sample dose with money choices presented in descending values. Enadoline (80 microg/70 kg) significantly (p < 0.05) reduced some of the positive subjective effects of cocaine (e.g., ratings of "high"), while butorphanol failed to modify subjective responses. Both agents were safely tolerated in combination with cocaine without adverse physiological responses. Cocaine self-administration was significantly greater across all pretreatment conditions when the sample dose was given and ascending money choices were used. Enadoline and butorphanol failed to modify cocaine self-administration. These data suggest that these kappa-agonists may be safely administered in the presence of cocaine but do not produce significant attenuation of cocaine's direct effects or self-administration under these acute dosing conditions.

Adult↗

PubMed2002

Butorphanol decreases edema following carrageenan-induced paw inflammation in rats.

The objectives of this study were to evaluate the anti-inflammatory effects and possible drug interactions of butorphanol by using carrageenan-induced paw inflammation in rats. We injected the right hind footpads of 64 female Sprague-Dawley rats (approximate weight, 100 g) with 50 microL of a 0.5% solution of carrageenan. Indomethacin (0, 1, 2.5, or 5 mg/kg) was administered by gavage to each of four groups 1 h prior to carrageenan injections. Half of the animals in each group received butorphanol (2 mg/kg) subcutaneously 1 h prior to carrageenan injections. Butorphanol decreased paw inflammation following carrageenan injections with or without concurrent administration of indomethacin. No drug interaction with indomethacin was observed. In conclusion, when using butorphanol for its analgesic properties, investigators should be mindful of the drug's anti-inflammatory effects, which may interfere with the experimentation.

Analgesics, Opioid↗

PubMed2004

The efficacy and safety of transnasal butorphanol for postoperative pain control following lower laparoscopic surgery.

BACKGROUND: The aim of the study was to evaluate the efficacy and safety of transnasal butorphanol for postoperative analgesia in adult female patients undergoing lower laparoscopic surgery. METHODS: Fifty-six women undergoing lower laparoscopic surgery under general anesthesia were enrolled in the study. They were randomly divided into 2 groups (n = 28 each). Postoperatively, group 1 received transnasal butorphanol 2 mg, whereas group 2 received transnasal placebo. During a 6-h post-treatment period, we collected the following data: scores of visual analogue pain scale, demand and delivery of patient-controlled analgesia (PCA) morphine, vital signs, nausea, vomiting, and somnolence. RESULTS: Transnasal butorphanol clearly proved to have analgesic effect when compared with placebo as revealed by diminishment of visual analogue scale scores at 30 min (P = 0.043), less consumption of PCA morphine at 30-60 min (P = 0.002), and less demand of PCA morphine at 30-60 min (P = 0.001) and 60-180 min (P = 0.031). All patients displayed stable vital signs. The side effects between groups were not significantly different. CONCLUSIONS: In contrast with placebo transnasal butorphanol was effective in the treatment of postoperative pain in female patients undergoing lower laparoscopic surgery. It had minimum side effects.

Administration, Intranasal↗

PubMed1992

Butorphanol tartrate (Stadol) relieves postanesthesia shaking more effectively than meperidine (Demerol) or morphine.

The cause of postanesthesia shaking (PS) is unknown. PS develops spontaneously and unpredictably in up to 67% of patients emerging from general anesthesia, and it continues for minutes to hours when not treated with medications or radiant heat lamps. The purposes of this study were to (1) examine whether butorphanol tartrate (Stadol; Anaquest, Madison, WI/Bristol-Meyers Squibb, Evansville, IN), meperidine (Demerol; Winthrop, NY, NY), and morphine are differentially effective in suppressing PS, (2) compare PS suppression by sex, and (3) determine time to PS development. PS, measured on a 0 to 3 visual scale, developed in 120 of 533 patients (23%). Medication treatment was initiated for 66 of 120 patients by PACU nurses following standard policies and procedures for intravenous doses of 1 mg butorphanol (n = 12), 15 to 30 mg meperidine (n = 18; n = 23), or 2 to 4 mg morphine (n = 13). Treatment effect was measured in units on a 0 to 2 visual scale. By t test, butorphanol is more effective within 2 minutes than meperidine for suppressing shaking alone (P less than .02) or shaking among patients also complaining of pain (P less than .02). Morphine does not relieve shaking. The chi 2 test indicates women suppress PS more rapidly than men (P less than .01), and PS develops within 5 minutes of PACU arrival (P less than .001). Findings suggest that butorphanol is an alternative PS treatment to meperidine, since it relieves shaking within 2 to 5 minutes without producing nausea, vomiting, or recurrence of shaking.

Adolescent↗

PubMedDate not supplied

Continuous infusion epidural anesthesia during labor: a randomized, double-blind comparison of 0.0625% bupivacaine/0.002% butorphanol and 0.125% bupivacaine.

The efficacy of pain relief and the maternal and neonatal effects of continuous epidural infusion of 0.0625% bupivacaine/0.002% butorphanol was compared with the infusion of 0.125% bupivacaine alone in a randomized, double-blind study of 32 women in labor. A test dose of 2 ml 0.5% bupivacaine was given to every patient and followed by two epidural regimens in randomized, double-blind manner. Group B-B (bupivacaine/butorphanol) patients received 7.5 ml 0.125% bupivacaine plus 1 mg butorphanol (0.5 ml) followed by an infusion of 0.0625% bupivacaine/0.002% butorphanol at a rate of 12 ml/hour; Group B (bupivacaine alone) patients received 8 ml 0.25% bupivacaine followed by an infusion of 0.125% bupivacaine at a rate of 12 ml/hour. A bolus of 5 ml 0.125% bupivacaine or 0.0625% bupivacaine was given to Group B or B-B, respectively, if additional pain relief was required. Infusion of B-B combination resulted in similar pain relief and fewer patients with motor block than bupivacaine alone; 12% versus 38% in Groups B-B and B, respectively, had motor weakness. A smaller dose of bupivacaine was used in the B-B group compared to the B group; 71 +/- 14 versus 99 +/- 13 mg (mean +/- SEM; p less than 0.05). Progress of labor and the mode of delivery did not differ significantly between the two groups. All infants were vigorous and had normal acid-base status and neurologic adaptive capacity scores. Butorphanol appears to be useful as an adjunct to epidural bupivacaine for continuous epidural infusion during labor without adversely affecting the mother or the neonate.

Adult↗

PubMed1990

Cardiovascular effects of butorphanol in halothane-anesthetized dogs.

Cardiovascular effects of butorphanol (0.2 mg/kg of body weight, IV) and responses associated with subsequent administration of naloxone (0.04 mg/kg, IV) were studied in halothane (1.2% end-tidal concentration)-anesthetized dogs. Transient, but statistically significant (P less than 0.05), decreases in heart rate, mean and diastolic arterial blood pressures, and rate-pressure product were observed after butorphanol administration. Cardiac index, stroke volume, and systemic vascular resistance did not change significantly. Except for the decrease in heart rate, changes in the values of the cardiovascular variables measured after butorphanol administration did not appear to be clinically relevant. Sixty minutes after butorphanol administration, naloxone was given. Statistically significant (P less than 0.05) increases in heart rate, arterial blood pressures, cardiac index, and rate-pressure product, along with dysrhythmias were observed. Stroke volume and systemic vascular resistance remained unchanged after administration of naloxone. Naloxone administration was associated with changes indicative of increased myocardial oxygen consumption.

Anesthesia, Inhalation↗

PubMed1989

[Optimum dose of intravenous butorphanol as a supplemental drug during regional anesthesia].

The optimum doses according to age of butorphanol tartrate as a supplemental drug during epidural and spinal anesthesia were investigated in 60 patients without complications. We classified patients into 4 groups by age as A, B, C and D-group. A-group consisting of patients between 20 to 40 years received 1.5mg of butorphanol. B-group 41-60, C-group 61-75 and D-group over 76 years received 1.0mg, 0.5mg and 0.25mg respectively. After operation was started without pain, and during the stable period, we determined by age, doses of butorphanol injected intravenously in one minute. HRs, mean BPs, respiratory rates (RRs) and so on were obtained at the preinjection point and 5 minutes after injection. In addition, in 15 patients, arterial blood gas analysis was performed at the same times. Butorphanol injections decreased HRs, mean BPs and RRs significantly. But there was no one whose PaCO2 increased more than 50 mmHg and no difference was found in degree of side effects between the groups. In conclusion, this study suggests that the decision to administer doses depending on the age is useful to decrease frequency of the grave side effects, especially respiratory depression which the elderly people frequently fall into.

Adult↗

PubMed1988

Randomized, prospective, double-blind clinical trial of butorphanol and diazepam in patients undergoing upper gastrointestinal endoscopy.

Premedication that provides sedation and analgesia is commonly used for patients undergoing endoscopic procedures. We studied the efficacy and safety of butorphanol and diazepam as preprocedure medications for patients having upper gastrointestinal endoscopy. To achieve an adequate level of sedation, patients receiving diazepam required a mean (+/- SEM) dose of 12.0 +/- 1.0 mg, whereas those receiving butorphanol required a mean dose of 4.8 +/- 0.4 mg. There were no differences between treatment groups in the overall assessment of sedation, the ease of performance of the endoscopic procedure, or vital signs during or following the procedure. Fifty-four percent of butorphanol patients and 48% of diazepam patients experienced at least one minor adverse event. Butorphanol in small doses can produce satisfactory sedation and analgesia for patients undergoing gastrointestinal endoscopic procedures.

Adolescent↗

PubMed1988

Effect of butorphanol, pentazocine, meperidine, or metoclopramide on intestinal motility in female ponies.

Effect of butorphanol, pentazocine, meperidine, and metoclopramide on jejunal and pelvic flexure myoelectric and mechanical activity in 4 female ponies was investigated. The agent to be tested or saline solution was administered IV at the start of a 6-hour recording trial. In the jejunum, duration between activity fronts of regular spiking activity, defined as the length of the migrating myoelectric complex (MMC), was measured. The average duration of the MMC during control trials was 150 +/- 46 minutes. The average duration of the MMC after meperidine, butorphanol, pentazocine, and metoclopramide administration was 295 +/- 70 minutes, 260 +/- 60 minutes, 275 +/- 60 minutes, and 163 +/- 64 minutes, respectively. Meperidine, butorphanol, or pentazocine significantly increased the MMC duration (P less than 0.05), and did not significantly alter the pelvic flexure activity. Seemingly, meperidine, butorphanol, and pentazocine inhibited cyclic myoelectric activity in the jejunum. Metoclopramide had no effect on jejunal or pelvic flexure motility.

Analgesics↗

PubMed1987

Respiratory effects of nalbuphine and butorphanol in anesthetized patients.

A double-blind, randomized study was conducted in 16 patients who were anesthetized with 50% nitrous oxide in oxygen and given either 0.17 mg/kg butorphanol or 0.86 mg/kg nalbuphine, and whose respiratory depression was assessed by the response of minute ventilation to increasing carbon dioxide concentrations. The slopes of the carbon dioxide ventilatory response curves [delta VE/delta PCO2(L.min-1 X %CO2(-1)] were 7.45 +/- 1.17 with nalbuphine and 2.42 +/- 0.56 with butorphanol. Butorphanol caused significantly (P less than 0.025) greater respiratory depression than nalbuphine. The results of this study caution against the indiscriminate use of butorphanol in the perianesthetic setting.

Anesthesia, General↗

PubMed1984

Effects of butorphanol, flunixin, levorphanol, morphine, and xylazine in ponies.

The analgesic and behavioral effects of butorphanol (0.22 mg/kg), flunixin (2.2 mg/kg), levorphanol (0.033 mg/kg), morphine (0.66 mg/kg), and xylazine (2.2 mg/kg), given IM were observed in 8 ponies. These ponies were instrumented to measure response objectively to painful superficial and visceral stimuli. Effects on the cardiopulmonary system and rectal temperature also were evaluated in 6 of these ponies. Observations were conducted before drug injection (base-line values) and after injection at 30, 60, 120, 180, and 240 minutes. Xylazine provided the highest pain threshold for the first 60 minutes and a sedative effect for 105 minutes. The effects for superficial pain and visceral pain persisted 3 hours and 4 hours, respectively. Morphine produced good analgesia for superficial pain (30 minutes), whereas butorphanol provided good effect for visceral pain (4 hours). A slight degree of analgesia for visceral pain was obtained after morphine (1 hour) and levorphanol (4 hours); flunixin did not induce analgesia. Butorphanol, levorphanol, and morphine stimulated motor activity. Behavioral effects did not occur after flunixin was given. Xylazine decreased systolic, diastolic, and mean blood pressures. Marked increases in these pressures, heart rate, and respiratory rate were observed after morphine was given. Changes of central venous pressure, rectal temperature, and blood gas values remained within base-line limits after both drugs were given. Butorphanol increased heart rates for 1 hour; flunixin and levorphanol did not alter any of the above values.

Analgesia↗