The absolute bioavailability and pharmacokinetics of butorphanol nasal spray in patients with hepatic impairment

Effectiveness of Butorphanol in alleviating intra- and post-operative visceral pain following microwave ablation for hepatic tumor: a dual-central, randomized, controlled trial

Many patients who underwent hepatic percutaneous microwave ablation (MWA) reported experiencing pain during the procedure. This study utilized a well-designed multicentral, randomized, and placebo-controlled format to investigate the effects of Butorphanol. Patients who underwent MWA were randomly assigned to either Butorphanol or normal saline group. The primary outcomes of the study were assessed by measuring the patients' intraoperative pain levels using a 10-point visual analog scale (VAS). Secondary outcomes included measuring postoperative pain levels at the 6-h mark (VAS) and evaluating comprehensive pain assessment outcomes. A total of 300 patients were divided between the control group (n = 100) and the experimental group (n = 200). Butorphanol showed statistically significant reductions in intraoperative pain levels compared to the placebo during surgery (5.00 ± 1.46 vs. 3.54 ± 1.67, P < 0.001). Significant differences were observed in postoperative pain levels at the 6-h mark and in the overall assessment of pain (1.39 + 1.21 vs. 0.65 + 0.81, P < 0.001). Butorphanol had a significant impact on reducing the heart rate of patients. The empirical evidence supports the effectiveness of Butorphanol in reducing the occurrence of visceral postoperative pain in patients undergoing microwave ablation for hepatic tumor. Furthermore, the study found no noticeable impact on circulatory and respiratory dynamics.

Pharmacokinetics and selected behavioral responses to butorphanol and its metabolites in goats following intravenous and intramuscular administration

OBJECTIVE

To evaluate disposition of a single dose of butorphanol in goats after intravenous (IV) and intramuscular (IM) administration and to relate behavioral changes after butorphanol administration with plasma concentrations.

DESIGN

Randomized experimental study.

ANIMALS

Six healthy 3-year-old neutered goats (one male and five female) weighing 46.5 ± 10.5 kg (mean ± D).

METHODS

Goats were given IV and IM butorphanol (0.1 mg kg^-1) using a randomized cross-over design with a 1-week interval between treatments. Heparinized blood samples were collected at fixed intervals for subsequent determination of plasma butorphanol concentrations using an enzyme linked immunosorbent assay (ELISA). Pharmacokinetic values (volume of distribution at steady state [Vd_SS], systemic clearance [Cl_TB], extrapolated peak plasma concentration [C₀] or estimated peak plasma concentration [C_MAX], time to estimated peak plasma concentration [T_MAX], distribution and elimination half-lives [t_1/2], and bioavailability) were calculated. Behavior was subjectively scored. A two-tailed paired t-test was used to compare the elimination half-lives after IV and IM administration. Behavioral scores are reported as median (range). A Friedman Rank Sums test adjusted for ties was used to analyze the behavioral scores. A logit model was used to determine the effect of time and concentration on behavior. A value of p < 0.05 was considered significant.

RESULTS

Volume of distribution at steady state after IV administration of butorphanol was 1.27 ± 0.73 L kg^-1, and Cl_TB was 0.0096 ± 0.0024 L kg^-1 minute^-1. Extrapolated C₀ of butorphanol after IV administration was 146.5 ± 49.8 ng mL^-1. Estimated C_MAX after IM administration of butorphanol was 54.98 ± 14.60 ng mL^-1, and T_MAX was 16.2 ± 5.2 minutes; bioavailability was 82 ± 41%. Elimination half-life of butorphanol was 1.87 ± 1.49 and 2.75 ± 1.93 hours for IV and IM administration, respectively. Goats became hyperactive after butorphanol administration within the first 5 minutes after administration. Behavioral scores for goats were significantly different from baseline at 15 minutes after IV administration and at 15 and 30 minutes after IM administration. Both time and plasma butorphanol concentration were predictors of behavior. Behavioral scores of all goats had returned to baseline by 120 minutes after IV administration and by 240 minutes after IM administration. Conclusions and Clinical Relevance  The dose of butorphanol (0.1 mg kg^-1, IV or IM) being used clinically to treat postoperative pain in goats has an elimination half-life of 1.87 and 2.75 hours, respectively. Nonpainful goats become transiently excited after IV and IM administration of butorphanol. Clinical trials to validate the efficacy of butorphanol as an analgesic in goats are needed.

Analgesic efficacy of tramadol and butorphanol in mandibular third molar surgery: a comparative study

BACKGROUND

Butorphanol tartrate, a mixed synthetic agonistantagonist opioid analgesic has been used for management of postoperative pain in minor and major surgical procedures.(14,20) Tramadol hydrochloride is a centrally acting opioid which is effectively used in postoperative pain in various minor and major surgeries.

MATERIALS AND METHODS

Twenty subjects selected randomly received butorphanol tartrate 1 mg intramuscular and 20 subjects received tramadol hydrochloride 50 mg intramuscular after the removal of mandibular third molars. Time of injection, amount of anesthetic injected, duration of surgery, adverse effects were recorded.(21)

RESULTS

The mean amount of LA administered in butorphanol group was 2.6450 ml and in tramadol group was 2.640 ml respectively, the mean duration for surgery was 56.75 and 53.5 minutes for butorphanol and tramadol groups respectively which was statistically not significant. Pain assessment was done with VAS which showed mean of 19.2 and 15.5 mm (p = 0.001) which was significant for butorphanol and tramadol respectively after 12 hours. The mean time for rescue medication requirement was 5.9 hours (for tramadol) and 8.4 hours (for butorphanol). Effective analgesic activity was seen by butorphanol 1 mg intramuscular then tramadol 50 mg.

CONCLUSION

Butorphanol 1 mg was more effective than tramadol 50 mg in respect to postoperative analgesia.

Intranasal drug delivery: an efficient and non-invasive route for systemic administration: focus on opioids

Intranasal administration is a non-invasive route for drug delivery, which is widely used for the local treatment of rhinitis or nasal polyposis. Since drugs can be absorbed into the systemic circulation through the nasal mucosa, this route may also be used in a range of acute or chronic conditions requiring considerable systemic exposure. Indeed, it offers advantages such as ease of administration, rapid onset of action, and avoidance of first-pass metabolism, which consequently offers for example an interesting alternative to intravenous, subcutaneous, oral transmucosal, oral or rectal administration in the management of pain with opioids. Given these indisputable interests, fentanyl-containing formulations have been recently approved and marketed for the treatment of breakthrough cancer pain. This review will outline the relevant aspects of the therapeutic interest and limits of intranasal delivery of drugs, with a special focus on opioids, together with an in-depth discussion of the physiological characteristics of the nasal cavity as well as physicochemical properties (lipophilicity, molecular weight, ionisation) and pharmaceutical factors (absorption enhancers, devices for application) that should be considered for the development of nasal drugs.

Opioid rotation: the science and the limitations of the equianalgesic dose table

Opioid rotation refers to a switch from one opioid to another in an effort to improve the response to analgesic therapy or reduce adverse effects. It is a common method to address the problem of poor opioid responsiveness despite optimal dose titration. Guidelines for opioid rotation are empirical and begin with the selection of a safe and reasonably effective starting dose for the new opioid, followed by dose adjustment to optimize the balance between analgesia and side effects. The selection of a starting dose must be based on an estimate of the relative potency between the existing opioid and the new one. Potency, which is defined as the dose required to produce a given effect, differs widely among opioids, and among individuals under varying conditions. To effectively rotate from one opioid to another, the new opioid must be started at a dose that will cause neither toxicity nor abstinence, and will be sufficiently efficacious in that pain is no worse than before the change. The estimate of relative potency used in calculating this starting dose has been codified on "equianalgesic dose tables," which historically have been based on the best science available and have been used with little modification for more than 40 years. These tables, and the clinical protocols used to apply them to opioid rotation, may need revision, however, as the science underlying relative potency evolves. Review of these issues informs the use of opioid rotation in the clinical setting and defines key areas for future research.

Bioavailability of intranasal butorphanol administered from a single-dose sprayer

PURPOSE

The bioavailability and tolerability of single doses of intranasal butorphanol tartrate using a single-dose, metered sprayer were studied.

METHODS

In this open-label, randomized, three-way crossover study, 24 healthy volunteers received three treatments: (1) 2 mg of i.v. butorphanol (treatment A), (2) 2 mg of intranasal butorphanol (treatment B), and (3) 1 mg of intranasal butorphanol (treatment C). The three treatments received by each subject were separated by six-day washout periods. Venous blood samples (10 mL each) were obtained from an indwelling catheter at 0 (predose), 5, 10, 15,20,30, and 45 minutes and 1,2,3,4,6,8, 12, and 16 hours after butorphanol administration. Pharmacokinetic parameters were determined using standard noncompartmental methods with log-linear least-squares regression analysis to determine the elimination-rate constants.

RESULTS

Intranasal butorphanol 1 and 2 mg administered using unit dose sprayers had a mean bioavailability of approximately 80%, which is higher than the percentage reported with the commercially available multidose product (61-69%). The absorption of intranasal butorphanol was rapid, with a median time to reach maximum concentration of 20 minutes (range, 10-60 minutes). Elimination profiles were comparable among all treatments. There were no clinically significant changes in the results of physical examinations, nasal evaluations, or laboratory tests related to butorphanol treatment. Most adverse effects reported were mild to moderate and as expected for this drug.

CONCLUSION

Single-dose intranasal butorphanol was rapidly absorbed and had high absolute bioavailability in healthy volunteers.

Nasal administration of opioids for pain management in adults

BACKGROUND

Nasal administration of opioids may be an alternative route to intravenous, subcutaneous, oral transmucosal, oral or rectal administration in some patients. Key features may be self-administration, combined with rapid onset of action. The aim of this paper is to evaluate the present base of knowledge on this topic.

METHODS

The review is based on human studies found in Medline or in the reference list of these papers. The physiology of the nasal mucosa and some pharmaceutical aspects of nasal administration are described. The design of each study is described, but not systematically evaluated.

RESULTS

Pharmacokinetic studies in volunteers are reported for fentanyl, alfentanil, sufentanil, butorphanol, oxycodone and buprenorphine. Mean times for achieving maximum serum concentrations vary from 5 to 50 min, while mean figures for bioavailability vary from 46 to 71%. Fentanyl, pethidine and butorphanol have been studied for postoperative pain. Mean onset times vary from 12 to 22 min and times to peak effect from 24 to 60 min. There is considerable interindividual variation in pharmacokinetics and clinical outcome. This may partly be due to lack of optimization of nasal formulations. Patient-controlled nasal analgesia is an effective alternative to intravenous PCA. Adverse effects are mainly those related to the opioids themselves, rather than to nasal administration. Some experience with nasal opioids in outpatients and for chronic pain has also been reported.

CONCLUSION

Nasal administration of opioids has promising features, but is still in its infancy. Adequately designed clinical studies are needed. Improvements of nasal sprayer devices and opioid formulations may improve clinical outcome.

Pharmacokinetic interaction between butorphanol nasal spray and oral metoclopramide in healthy women

The pharmacokinetics of butorphanol nasal spray, with and without the coadministration of metoclopramide, were studied in 24 healthy women. In this crossover study all volunteers received 3 treatments: a single, 1-mg dose of butorphanol nasal spray, a single, 10-mg oral dose of metoclopramide, and a combination of a single, 1-mg dose of butorphanol nasal spray and a single, 10-mg oral dose of metoclopramide. There was at least a one-week washout period between sessions. Serial blood samples were collected and plasma samples analyzed using a validated radioimmunoassay to determine the concentration of butorphanol, or a high-performance liquid chromatography/ultraviolet procedure was used to determine the concentration of metoclopramide. There were no statistically significant differences in the pharmacokinetic parameters, Cmax, tmax, AUC, and t1/2, for butorphanol with or without metoclopramide. Similarly, except for a delay in tmax of metoclopramide with coadministration of butorphanol, the pharmacokinetic parameters of metoclopramide were not significantly different between two treatments. Thus, the pharmacokinetics of both butorphanol and metoclopramide were not significantly altered when administered in combination. The incidence of nausea/vomiting after butorphanol administration was substantially reduced by coadministration of metoclopramide. Based on the pharmacokinetic and safety results, it can be concluded that butorphanol nasal spray and metoclopramide can be administered in combination without altering the dose regimen of either drug.