Intranasal niosomes of nefopam with improved bioavailability: preparation, optimization, and in-vivo evaluation

OBJECTIVE

One of the greatest challenges drug formulation is facing is poor bioavailability via oral route. In this regard, nasal drug delivery has been commonly used as an alternative route to improve drug bioavailability. Nefopam hydrochloride (NF) is an analgesic drug that suffers from poor bioavailability due to extensive metabolism in liver. Accordingly, the goal of the present study was to improve NF bioavailability via niosomal-based formulation designed for intranasal delivery.

MATERIALS AND METHODS

Vesicles were developed by mixing surfactants (Span 20, Span 40, Span 80, and Span 85) at four molar ratios of 1:1, 1:2, 1:3, and 1:4 of cholesterol to surfactant. Entrapment efficiency, particle size, zeta potential, release percentage, ex-vivo permeation parameters, and niosomes' stability were determined. Also, the pharmacokinetic parameters of the optimized formula in in-situ gel base were measured in rats.

RESULTS

Niosomes showed entrapment efficiency .80%, particle size ,550 nm, and zeta potential ranging from -16.8±0.13 to -29.7±0.15. The produced vesicles showed significantly higher amounts of drug permeated across nasal mucosa (2.5 folds) and prolonged NF release compared with NF solution. Stability studies of optimum formula showed nonsignificant changes in niosomes parameters over a storage period of 6 months. The in-vivo studies showed a 4.77-fold increase in bioavailability of optimized nasal niosomes compared with oral solution of drug.

CONCLUSION

The obtained results revealed the great ability of the produced NF-loaded nio-somes to enhance drug penetration through nasal mucosa and improve its relative bioavailability compared with NF oral solution.

Association of nefopam use with postoperative nausea and vomiting in gynecological patients receiving prophylactic ramosetron: A retrospective study

Background

Postoperative nausea and vomiting (PONV) is a common adverse effect of opioid-based intravenous patient-controlled analgesia (IV PCA). Nefopam has been considered as a good candidate for inclusion in multimodal analgesia because of its opioid sparing effect, but it can be emetic. This study aims to examine whether the use of nefopam combined with fentanyl in IV PCA was associated with the higher incidence of PONV in patients receiving prophylactic ramosetron after gynecological surgery.

Methods

Data from 296 patients who underwent gynecological surgery were retrospectively reviewed. The patients received IV PCA containing either fentanyl 1500 μg and ketorolac 90 mg (Group K) or fentanyl 1500 μg and nefopam 80 mg (Group N). All patients in both groups received 0.3 mg of ramosetron at the end of surgery. The primary outcome measure was the incidence of PONV during the 3-day postoperative period.

Results

No difference was observed in the incidence of PONV during the 3-day postoperative period between the two groups. However, the incidence of nausea on postoperative day 2 was significantly higher in Group N (10.3%) than in Group K (2.8%) (P = 0.016). Multivariable logistic regression analysis showed that the use of nefopam was not associated with a higher incidence of PONV (adjusted odds ratio, 1.616; 95% confidence interval, 0.952–2.743, P = 0.076). There were no differences in postoperative pain scores between the two groups.

Conclusion

The combined use of nefopam with fentanyl in IV PCA was not associated with the higher incidence of PONV compared with the use of ketorolac and fentanyl combination in patients who received ramosetron as PONV prophylactic agent. However, prospective trials are required for a confirmative conclusion.

The efficacy and safety of nefopam for pain relief during laparoscopic cholecystectomy: A meta-analysis

BACKGROUND

Pain control after laparoscopic cholecystectomy (LC) has become an important topic. We performed a meta-analysis of randomized controlled trials (RCTs) to evaluate the efficacy and safety of nefopam for pain management after LC.

METHODS

PubMed, Medline, Embase, ScienceDirect, and the Cochrane Library were searched up to November 2017 for comparative articles involving nefopam and placebo for reducing postoperative pain after LC. Primary outcomes were postoperative pain scores and opioid consumption. Secondary outcomes were length of hospital stay, opioid-related adverse effects, and postoperative complications. We assessed statistical heterogeneity for each RCT by using a standard Chi test and the I statistic. The meta-analysis was undertaken using Stata 12.0.

RESULTS

A total of 215 patients were analyzed across 4 RCTs. We found that there were significant differences between nefopam and placebo groups regarding the postoperative pain scores and opioid requirements at 6, 12, and 24 hours. Moreover, there was a decreased risk of opioid-related adverse effects in the nefopam groups. No significant differences were identified in terms of the incidence of postoperative complications.

CONCLUSION

Intravenous nefopam infusion resulted in significant reduction in postoperative pain scores and opioid requirements while decreasing opioid-related adverse effects. Additionally, no increased risk of venous thromboembolism was found. The current evidence suggests that more RCTs will be needed in further investigations.

Effects of nefopam on emergence agitation after general anesthesia for nasal surgery: A prospective, randomized, and controlled trial

BACKGROUND

Emergence agitation (EA) occurs frequently after nasal surgery. N-methyl-D-aspartate (NMDA) receptor antagonists and analgesics, such as fentanyl, have been shown to prevent EA. Nefopam inhibits the NMDA receptor and shows a potent analgesic effect. We investigated the effects of nefopam on EA in patients undergoing nasal surgery.

METHODS

In this prospective, double-blind study, 100 adult patients were allocated randomly to 1 of 2 groups (each n = 50). Patients received 20 mg of nefopam in 98 mL of saline for 20 minutes immediately after induction of anesthesia (nefopam group) or 100 mL of saline (control group) in the same manner. After surgery, the incidence and degree of EA, time for extubation, hemodynamic parameters, and adverse events were evaluated by an observer blinded to the group allocation.

RESULTS

The overall incidence of EA was lower in the nefopam group than in the control group (34% [17/50] vs 54% [27/50], respectively; P = .044). The incidence of severe EA was also lower in the nefopam group than in the control group (8% [4/50] vs 38% [19/50], respectively; P = .001). Heart rate (HR) was higher in the nefopam group than in the control group from the end of surgery to 3 minutes after extubation (P = .008). Time for extubation and adverse events were similar between groups.

CONCLUSIONS

Nefopam infusion is effective in preventing and reducing the severity of EA after nasal surgery without a delay in extubation. However, caution is required regarding the increase in HR.

Nefopam Abuse

OBJECTIVE:

To report 3 patients who abused nefopam, a central analgesic that inhibits serotonin, norepinephrine, and dopamine reuptake.

CASE SUMMARIES: CASE 1:

A 42-year-old white woman with migraines started nefopam therapy about 10 years ago. She now obtains nefopam by prescription forgery and self-administers intramuscular nefopam 300 mg/d. She experiences anticholinergic effects of nefopam and, when attempting withdrawal, depressive symptoms. CASE 2: A 40-year-old white woman with osteoporosis has injected 120 mg of nefopam intramuscularly daily for several years. When she tried to increase doses due to worsening of her symptoms, she experienced tremor, involuntary movements, and dry mouth, and became aggressive. She then resumed the initial doses. She now reports symptoms of depression when attempting withdrawal. CASE 3: A 33-year-old white man, with a history of alcohol and benzodiazepine dependence and ileostomy, and an implanted drug delivery system, has been prescribed nefopam. Fifteen days after therapy was initiated, his daily consumption was 840 mg/d, and further increased to 1840 mg/d. He experienced violent behavior, agitation, facial dysesthesia and myoclonus, tremor of fingers, and sweating. He did not attempt withdrawal.

DISCUSSION:

The patients described above are drug-dependent according to the Diagnostic and Statistical Manual, 4th Edition. All patients developed a pharmacodynamic tolerance phenomenon, which can develop rapidly. Violent behavior, tremor after massive intake, and depressive symptoms during withdrawal are similar to those reported with psychostimulant abuse.

CONCLUSIONS:

When abused, nefopam has primarily psychostimulant-like effects, which are probably linked to its dopamine reuptake inhibition properties.

THE USE OF DEXMEDETOMIDINE IN COMBINATION NEFOPAM FOR POSTOPERATIVE ANALGESIA AFTER LAPAROSCOPIC CORRECTION OF MORBID OBESITY

AIM

To study the possibility of using a combination of dexmedetomidine with nefopam for postoperative analgesia in patients with morbid obesity after bariatric surgery in anesthesia quality aspects and theimpact of the study on the combination during the inflammatory response to surgical trauma.

SUBJECTS AND METHODS

A prospective cohort study of 48 patients with obesity.

RESULTS

Based on the analysis of hemodynamic parameters, evaluation of pain using a numeric rating scale pain concluded that selective agonist of o-2 adrenergic dexmedetomidine in combination with nefopam provides effective postoperative pain relief in patients who underwent bariatric surgery, and is not a factor for suppression of postoperative inflammatory response Unlike the effects of ketorolac tromethamine, do not always provide a sufficient level of analgesia and reduce the rate of growth in the level of IL-6.

CONCLUSION

The combination of dexmedetomidine with nefopam provides sufficient analgesic effect after bariatric surgery, with noted a more rapid onset of analgesia than with ketorolac. Postoperative analgesia and dexmedetomidine nefopam, unlike the use of ketorolac tromethamine, are not violated ratio of interleukins 1 and 6 was not a factor and suppression of postoperative acute phase inflammatory response.

Effect of nefopam- versus fentanyl-based patient-controlled analgesia on postoperative nausea and vomiting in patients undergoing gynecological laparoscopic surgery: a prospective double-blind randomized controlled trial

OBJECTIVE

This study comparatively evaluated the effect of patient-controlled analgesia (PCA) regimens using equipotent doses of nefopam or fentanyl during laparoscopic gynecological surgery on postoperative nausea and vomiting (PONV).

RESEARCH DESIGN AND METHODS

Patients undergoing gynecological laparoscopic surgery were randomly allocated to receive either nefopam- (non-opioid; N group) or fentanyl-based (F group) PCA. PONV and postoperative pain were assessed during the 72 hours following discharge from the post-anesthetic care unit (PACU). The adverse effects of nefopam were also evaluated.

CLINICAL TRIAL REGISTRATION

Cris.nih.go.kr ID KCT0000783.

RESULTS

In total, 94 patients were included in the final analysis. The PONV incidence and scale and the Rhodes index scores were significantly lower in the N group than the F group at all measured times. The N group exhibited a significantly lower incidence of PONV (15/47 [31.9%] vs. 27/47 [57.4%], respectively; P = 0.022) and severity of PONV (0 [1] vs. 1 [2], respectively; P = 0.005) 24 hours after PACU discharge and a significantly lower Rhodes index score (0 [3] vs. 5 [9], respectively; P = 0.002) from 30 minutes after PACU arrival to 24 hours after PACU discharge than did the F group. There was no significant difference in postoperative pain at any time between the two groups. Dry mouth on PACU arrival was significantly more frequent in the N group. However, the frequency of dry mouth decreased after PACU arrival in the N group, resulting in a significantly lower incidence 24 hours after PACU discharge.

CONCLUSIONS

Use of a PCA regimen with nefopam for analgesia was associated with a similar degree of pain control and superior PONV outcomes 24 hours after PACU discharge and no adverse events compared with a PCA regimen using an equipotent dose of fentanyl.

Mechanical Antiallodynic Effect of Intrathecal Nefopam in a Rat Neuropathic Pain Model

Nefopam has a pharmacologic profile distinct from that of opioids or other anti-inflammatory drugs. Several recent studies demonstrate that nefopam has a mechanism of action similar to those of anti-depressants and anticonvulsants for treating neuropathic pain. The present study investigates the mechanical antiallodynic effect of nefopam using immunohistochemical study and western blot analysis in a rat neuropathic pain model. Twenty-eight male Sprague-Dawley rats were subjected to left fifth lumbar (L5) spinal nerve ligation and intrathecal catheter implantation, procedures which were not performed on the 7 male Sprague-Dawley rats in the sham surgery group (group S). Nefopam, either 10 or 100 µg/kg (group N10 or N100, respectively), and normal saline (group C) were intrathecally administered into the catheter every day for 14 days. The mechanical allodynic threshold of intrathecal nefopam was measured using a dynamic plantar aesthesiometer. Immunohistochemistry targeting cluster of differentiation molecule 11b (CD11b) and glial fibrillary acidic protein (GFAP) was performed on the harvested spinal cord at the level of L5. Extracellular signal-regulated kinase 1/2 (ERK 1/2) and cyclic adenosine monophosphate response element binding protein (CREB) were measured using western blot analysis. The N10 and N100 groups showed improved mechanical allodynic threshold, reduced CD11b and GFAP expression, and attenuated ERK 1/2 and CREB in the affected L5 spinal cord. In conclusion, intrathecal nefopam reduced mechanical allodynia in a rat neuropathic pain model. Its mechanical antiallodynic effect is associated with inhibition of glial activation and suppression of the transcription factors' mitogen-activated protein kinases in the spinal cord.

[Thrombocytopenia and postoperative analgesia]

OBJECTIVE

To develop effective and safe measures of postoperative multimodal analgesia (optimizing the use of narcotic analgesics) in surgical treatment of hematological patients with thrombocytopenia.

DESIGN

A pilot and prospective comparative controlled study.

METHODS

We studied 27 patients with acquired thrombocytopenia who underwent laparoscopic splenectomy. Three schemes of anesthesia were used: 1) Nefopam 20 mg/day + trimeperidin (n = 7); 2) Paracetamol 4 g/day + trimeperidin (n = 10); 3) paracetamol + trimeperidin + glucocorticosteroids (GC) (through treatment of the underlying disease) (n = 10). Analgesic properties and effect of each scheme were assessed according to a rating scale of pain NRS (10 points) and VAS (100 points) studied. Additionally we evaluated the effect of nefopam and paracetamol on the functional properties of platelets and hemostasis, platelet levels while monitoring and indicators of thromboelastogram (TEG).

RESULTS

Application of paracetamol + trimeperidin accompanied with effectively reducing of postoperative pain (less than 5 points on the NRS). The level of postoperative pain was lower in patients who were treated with corticosteroids within the therapy of the underlying disease before surgery and who continued to receive it in postoperative period (2-3 points NRS). Nefopam use in the perioperative period is not only inferior to the analgesic effect of paracetamol, but also causes frequent side effects. Consumption of narcotic analgesic--trimeperidin when applying nefopam averaged 43 mg/day, the appointment of paracetamol--28 mg/day, using a combination of paracetamol + GC--20 mg/day. Thus, GC within the underlying disease treatment substantially reduces the need for opioid analgesics. A monitoring of the number of platelets and TEG did not shows negative effect of paracetamol and nefopam on platelet and plasma hemostasis.

CONCLUSIONS

Nefopam and paracetamol may be used in patients with thrombocytopenia, as do not affect the hemostasis and platelet count. Application of postoperative analgesia scheme paracetamol + trimeperidin in patients receiving corticosteroids provides the maximum reduction of pain with the least consumption of narcotic analgesics.

[Postoperative analgesia with nefopam and non-steroidal anti-inflammatory drugs in patients after surgery for tumors of head and neck]

MATERIALS AND METHODS

83 adult patients included in the study were divided into two groups. Patients of the group-1 (n-49) had medium level of pain after cancer head and neck surgery. Patients of the group-2 (n-34) had severe pain. Three first postoperative days their post-operative multimodal analgesia started with tenoxycam 20 mg i.m. after induction of anesthesia, then every 24 hour (58 patients). 25 patients got ketoprofen 100 mg i.m. every 8-12 hours instead of tenoxycam. All patients had nefopam 30 mg i.m. 30 min prior the end of surgery procedure, and every 8 hours afterwards. 7 patients of the group-1 had more than 4 pain scores (day 1), 4 patients--at the day 2. They received tramadol or paracetamol additionally. 7 patients (group-2) also had up to 5 pain scores on the day 1, 5 patients had 4 pain scores on the day 2, and 3 patients 4 pain scores on the day 3. All that patients received additional analgesia with tramadol or trimeperidine once a day. 8.4% of patients suffered from adverse reactions (tachycardia, PONV and sweating).

CONCLUSION

This method of multimodal postoperative analgesia is very simple and fairly efficient.

[Ketoprophen and nefopam combination for postoperative analgesia with minimal use of narcotic analgesics in cardio-surgical patients]

4 combinations of analgesia were studied: 1) Nefopam and patient-controlled analgesia (PCA) with Trimeperidine; 2) Ketoprofen (100 microg each 12 hours intramuscular) and PCA with Trimeperidine; 3) Nefopam, Ketoprofen and PCA with Trimeperidine; 4) PCA with Trimeperidine as monotherapy in early postoperative period in cardio-surgical patients. 80 patients (age from 40 to 70) were divided into 4 groups, 20 patients in each group. Administration of Nefopam and Ketoprofen before extubation reduced the intensity of pain syndrome (in average on 90%) and promoted the early stirring up of patients. Combination of Nefopam and Ketoprofen provided the most expressed analgesic and opioids-saving effects. In this group average amount of Trimeperidine per 24 hours was 14.7 microg that was 4.9 times less than in group of PCA with Trimeperidine as monotherapy. Dynamics of maximal inspiratory capacity of the lungs in the first three groups was better than in group of PCA with Trimeperidine as monotherapy beginning from 6th hour of study. In common undesirable effects was connected with Trimeperidine administration and depended on its dose. The frequency of nausea, vomit, dizziness and weakness was authentically higher in the group of PCA with Trimeperidine as monotherapy than in other groups.

[The use of central acting analgesic nefopam in postoperative analgesia in cardiac surgery patients]

A prospective, randomized, comparative study was conducted. 3 analgesia protocols were used: 1) patient controlled analgesia (PCA) with trimeperidine in combination with a nefopam constant infusion; 2) PCA with trimeperidine in combination with a nefopam bolus; 3) PCA with trimeperidine separately during early postoperative period in cardiac surgery patients. The study included 60 patients agedf rom 40 to 65 years of age (20 patients in each group). The analgesia efficacy was evaluated with a 5-point verbal rating scale (VRS) for pain intensity and inspiratory lung capacity (ILC), measured with incentive spirometer. The safety of nefopam during early postoperative period in cardiac surgery patients was shown. The combination of nefopam and trimeperidine led to a more pronounced analgetic effect. Trimeperidine consumption was significantly lower in nefopam groups than in the group of isolated PCA. Wholly adverse effects were associated with trimeperidine and were dose-related The incidence of nausea, vomiting, dizziness, weakness, bowel paresis was significantly higher in isolated PCA group than in the other two groups.

Median effective dose (ED50) of paracetamol and nefopam for postoperative pain: isobolographic analysis of their antinociceptive interaction

BACKGROUND

The analgesic efficacy of nefopam and of paracetamol has been shown in the postoperative period after mild- and moderate-pain surgery. The aim of this study was to define the median effective analgesic doses of each drug and of their combination, in order to determine the nature of their interaction.

METHODS

Ninety adult patients scheduled to undergo tonsillectomy under general anesthesia were enrolled in one out of three groups: nefopam group, or paracetamol group, or nefopam-paracetamol group. The median effective dose for each drug and also for their combination was defined using an up-and-down sequential allocation technique. The analgesic interaction of their combination was assessed using an isobolographic analysis.

RESULTS

The median effective analgesic dose (median value and 95% confidence interval) of nefopam and paracetamol were 21.7 mg (21.1-22.3 mg) and 628 mg (600-656 mg), respectively. The median effective analgesic doses of the combination were 8.9 mg (8.7-9.1 mg) for nefopam and 265 mg (256-274 mg) for paracetamol. The isobolographic analysis demonstrated a supra-additive interaction of the two drugs.

CONCLUSION

The combination of nefopam and paracetamol produces effective analgesia with a synergistic interaction.

[Comparison between two analgesic protocols on IVF success rates]

OBJECTIVES

Analgesic protocols administered before a follicular puncture under local anesthesia are well tolerated when using NSAIDs, but we still do not know their possible impacts on in vitro fertilization (IVF) outcomes.

MATERIAL AND METHODS

A retrospective monocentric study using two consecutive temporal cohorts of patients was conducted to compare two analgesic protocols: paracetamol/alprazolam (P/A), then nefopam/ketoprofen (N/K).

RESULTS

We demonstrated that biochemical pregnancy rate and the others outcomes of IVF are not significantly influenced by the type of analgesic protocol used.

CONCLUSION

The protocol N/K enhances patient comfort without jeopardizing the IVF success rates.

Development and evaluation of nefopam transdermal matrix patch system in human volunteers

Nefopam hydrochloride, a nonsteroidal anti-inflammatory drug, is administered in tablet form three times daily or as intramuscular injection at 6-h intervals to treat disorders such as acute or constant pain. It is also used for a prolonged treatment of severe pain, when morphine therapy has to be withdrawn for morphine-related dependence. To achieve a constant drug-plasma level of nefopam for a prolonged period, a transdermal drug delivery system was fabricated in our present study by employing suitable experimental hydrophilic and lipophilic polymeric combinations of polyvinyl pyrrolidone (PVP) and ethyl cellulose (EC). Physical studies including weight variation, moisture content, moisture uptake, flatness, external morphology of the formulations, and in vitro drug release were performed. Drug-excipient interaction studies were carried out using Fourier transform infrared spectroscopy. In vitro skin permeation study with cadaver skin was conducted using modified Keshary-Chein diffusion cells. Interactions between nefopam and PVP seem to contribute to the slow and controlled release pattern of nefopam. The scanning electron microscopy evaluation of prepared matrix patches revealed that drug was dispersed uniformly in polymeric matrix. In vitro drug release study showed that an increase in concentration of hydrophilic polymer, PVP, enhanced drug release substantially. In vitro skin permeation study showed variable permeation profiles of nefopam from the experimental patches. Among the formulations, PVP:EC (1:3) was found to provide slowest release and maximum sustained skin permeation of drug in vitro. Application of those patches, PVP:EC (1:3), on human volunteers was found to provide systemic availability of the drug till 48 h.

Single dose oral nefopam for acute postoperative pain in adults

BACKGROUND

Nefopam is a centrally-acting but non-opioid analgesic drug of the benzoxazocine chemical class, developed in the early 1970s. It is widely used, mainly in European countries, for the relief of moderate to severe pain as an alternative to opioid analgesic drugs, and used in rheumatic disease and other musculoskeletal disorders in the UK. This review sought to evaluate the efficacy and safety of oral nefopam in acute postoperative pain, using clinical studies of patients with established pain, and with outcomes measured primarily over 6 hours using standard methods. This type of study has been used for many decades to establish that drugs have analgesic properties.

OBJECTIVES

To assess the efficacy of single dose oral nefopam in acute postoperative pain, and any associated adverse events.

SEARCH STRATEGY

We searched CENTRAL (Issue 2, 2009), MEDLINE (1966 to May 2009); EMBASE via Ovid (1980 to May 2009); the Oxford Pain Relief Database (1950 to 1994); and reference lists of studies found.

SELECTION CRITERIA

Randomised, double-blind, placebo-controlled clinical trials of oral nefopam for relief of acute postoperative pain in adults.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. The area under the "pain relief versus time" curve was used to derive the proportion of participants with nefopam and placebo experiencing least 50% pain relief over 4 to 6 hours, using validated equations. The number-needed-to-treat-to-benefit (NNT) was calculated using 95% confidence intervals (CIs). The proportion of participants using rescue analgesia over a specified time period, and time to use of rescue analgesia, were sought as additional measures of efficacy. Information on adverse events and withdrawals was also collected.

MAIN RESULTS

No included studies were identified after examining in detail thirteen studies on oral nefopam in participants with established postoperative pain.

AUTHORS' CONCLUSIONS

In the absence of evidence of efficacy for oral nefopam in acute postoperative pain, its use in this indication is not justified. Because trials clearly demonstrating analgesic efficacy in the most basic of acute pain studies are lacking, use in other indications should be evaluated carefully. Given the large number of available drugs of this and similar classes, there is no urgent research agenda.

Cyclodextrin Inclusion Complexes of the Central Analgesic Drug Nefopam

Inclusion complexes of nefopam base (NEF) with various beta-cyclodextrins (betaCDs) were investigated. All tested betaCDs increased the apparent solubility of NEF according to a Higuchi AL type plot (except betaCD: AN type plot), which indicates the formation of 1:1 stoichiometry inclusion complexes. 1H-NMR and 13C-NMR experiments showed that complexation by CDs allowed an easy separation of the R and S enantiomers. Based on spectral data obtained from the two-dimensional rotating frame nuclear Overhauser effect spectroscopy (2D-ROESY), a reasonable geometry for the complexes could be proposed implicating the insertion of the benzoxazocine ring into the wide end of the torus cavity.

Analgesic efficacy of bilateral superficial cervical plexus block administered before thyroid surgery under general anaesthesia

BACKGROUND

The use of regional anaesthesia in thyroid surgery remains controversial. This double-blind, randomized controlled study was conducted to evaluate the analgesic efficacy of bilateral superficial cervical plexus block (BSCPB) performed under general anaesthesia in patients undergoing total thyroidectomy.

METHODS

Eighty-seven consecutive consenting patients were randomized to receive a BSCPB with saline (Group P, n = 29), ropivacaine 0.487% (Group R, n = 29), or ropivacaine 0.487% plus clonidine 5 microg ml(-1) (Group RC, n = 29). Sufentanil was given during the intraoperative period for a 20% increase in arterial mean pressure or heart rate in a patient with a bispectral index between 40 and 60. All patients received 4 g of acetaminophen during the first 24 h after operation. The pain score was checked every 4 h and nefopam was given for pain score >4 on a numeric pain scale.

RESULTS

During surgery, the median sufentanil requirements were significantly reduced in Group RC compared with Groups R and P (0.32 vs 0.47 and 0.62 microg kg(-1); P < 0.0001). After surgery, the number of patients requiring nefopam within 24 h of surgery was significantly lower in Groups R and RC than in Group P (16 and 19 vs 25; P = 0.03). At post-anaesthetic care unit admission, median (range) pain scores were significantly lower in Groups R [3 (0-10)] and RC [3 (0-8)] than in Group P [5 (0-8), P = 0.03]. No major complications of BSCPB occurred during study.

CONCLUSIONS

BSCPB with ropivacaine and clonidine improved intraoperative analgesia. BSCPB with ropivacaine or ropivaciane and clonidine was effective in reducing analgesic requirements after thyroid surgery.

Effective dose of nefopam in 80% of patients (ED80): a study using the continual reassessment method

AIMS

The effective dose in 50% of patients (ED(50)) is far from being relevant for clinical purposes. We used the continual reassessment method (CRM) to determine the effective dose of nefopam in 80% of the patients suffering from moderate pain in the postoperative period (ED(80)).

METHODS

Patients with a pain intensity >3 on a 1-10 numerical pain score (NPS) received increasing or decreasing doses of nefopam (20, 30, 40, 60, 80 mg) postoperatively. The criterion of success was a NPS <or=3, 30 min after the beginning of infusion. The initial dose was 20 mg and the subsequent doses were determined by the continuous reassessment method (CRM). The data were also fitted a posteriori with the maximum likelihood technique.

RESULTS

Twenty-four patients were enrolled. Nefopam 60 mg gave a probability of success of 0.818 (95% credibility interval 0.606-0.941). Using the maximum likelihood technique, we determined an ED(50) of 27.3 mg and a dose leading to a probability of 0.8 (ED(80)) of 74.4 mg. We did not observe a high incidence of side-effects.

CONCLUSIONS

The ED(80) of nefopam, close to 60 mg is higher than the usual dose of 20 mg. The CRM allowed us to determine the ED(80) of nefopam with reasonable accuracy in a small number of patients as compared with the classical dose-probability curve fitting. We did not observe an increased incidence of side-effects when compared with the literature or to our previous studies.

[What are the cardiovascular complications of the analgesics and glucocorticoids?]

When prescribing a non-steroidal anti-inflammatory treatment but also an analgesic or a glucocorticoid, the cardiovascular risk of the patient should be assessed. The analgesics have few cardiovascular side effects and the main complications observed are linked essentially to the vagal action of the opioids. Acetaminophen is considered by several scientific societies to be the first line analgesic treatment, particularly in case of cardiovascular risk but with caution since cardiovascular toxicity of acetaminophen cannot be totally excluded. An overdose of dextropropoxyphene can result in cardiotoxicity. On the other hand, the glucocorticoids need to be prescribed cautiously, at the lowest possible dose and for the shortest possible duration due to the non-negligible cardiovascular risk, hypertension, dyslipidemia, hypokaliemia.

Median effective dose (ED50) of nefopam and ketoprofen in postoperative patients: a study of interaction using sequential analysis and isobolographic analysis

BACKGROUND

The analgesic efficacy of ketoprofen has been shown after moderate- and severe-pain surgery, and the analgesic efficacy of nefopam has been shown after moderate-pain surgery. The aim of this study was to define the median effective analgesic doses of each drug and to determine whether the interaction of nefopam and of ketoprofen is synergistic.

METHODS

Seventy-two patients scheduled to undergo moderately painful surgery were enrolled in one of three groups. The dose of nefopam and ketoprofen received by a particular patient was determined by the response of the previous patient of the same group, using an up-and-down technique. Initial doses were 18 and 40 mg, with dose adjustment intervals of 2 and 5 mg, in the nefopam and ketoprofen groups, respectively. The initial doses of nefopam and ketoprofen were 8 and 20 mg, respectively, in the nefopam-ketoprofen group, with the same dose adjustment intervals. Analgesic efficacy was defined as a decrease to less than 3 on a 0-10 numeric pain scale, 45 min after the beginning of drug infusion.

RESULTS

The median effective analgesic dose (median value and 95% confidence interval) of nefopam and ketoprofen were, respectively, 28 mg (17-39 mg) and 30 mg (14-46 mg). The median effective analgesic dose of the combination was 1.75 mg (0.9-2.3 mg) for nefopam and 4.3 mg (2.2-6.5 mg) for ketoprofen.

CONCLUSION

The isobolographic analysis demonstrated that the combination of the two drugs produces effective analgesia with an important synergistic interaction.

Effets analgésiques de l'administration intraveineuse continue de néfopam après chirurgie urologique

OBJECTIVES

To evaluate the efficacy of continuous infusion of nefopam. Indeed this analgesic is commonly used by continuous infusion by many anaesthetists to reduce its adverse effects. However whether the analgesic effect of an intermittent administration of nefopam has been proven, the efficacy of continuous infusion has not been established.

STUDY DESIGN

Double-blind placebo controlled prospective randomised study.

PATIENTS AND METHODS

Sixty patients ASA 1 to 3 undergoing planned urological surgery with laparotomy were included. At the end of surgery, bolus doses of placebo (Group 3) or nefopam 20 mg (Group 1 and 2) were administered to all the patients. Placebo (Group 3), nefopam 80 mg (Group 1) or 120 mg (Group 2) was thereafter continuously infused over 24 hours. All patients received additional analgesia with PCA morphine. We measured pain at rest and on cough with VAS. Adverse side effects such as nausea and vomiting, sedation and respiratory depression were evaluated. Mental performance was measured with mini mental status tests.

RESULTS

Patients were older in the placebo group by approximately six years but anesthetic and surgical variables were not different between groups. Pain at rest and on cough was not statistically different between groups. In the placebo group, the median (interquartile range) morphine consumption reached 29 mg (13-53) whereas in patients receiving 80 and 120 mg nefopam, it levelled to 44 mg (11-54) and 35 mg (9-82) respectively (p > 0.05). Patients needed morphine during the same time period whether they received nefopam or not. Patients suffering from adverse effects were similar between groups.

CONCLUSION

In this study, continuous administration of nefopam did not reduce morphine consumption nor ameliorate analgesia and thus may not be recommended in urological surgery. Nefopam pharmacokinetics when used with continuous infusion as well as surgery types and differences in age between groups may explain these results.

A comparison of nefopam and clonidine for the prevention of postanaesthetic shivering: a comparative, double-blind and placebo-controlled dose-ranging study

Postanaesthetic shivering is a frequent complication following general anaesthesia. The aim of this study was to compare the effectiveness of three doses of nefopam with clonidine and placebo in the prevention of postanaesthetic shivering. We studied 371 patients undergoing abdominal or orthopaedic surgery. Patients were allocated to one of five groups: Group A (n = 73) received 0.2 mg x kg(-1) nefopam, Group B (n = 75) 0.1 mg x kg(-1) nefopam, Group C (n = 76) 0.05 mg x kg(-1) nefopam, Group D (n = 73) 1.5 microg x kg(-1) clonidine, and Group E (n = 74) saline 0.9% as placebo. We found a significant reduction in the incidence of shivering in Group A compared to Group C and clonidine as well as to the placebo group. All active treatments reduced the incidence and the severity of shivering compared to placebo. At 5 min postoperatively clonidine-treated patients showed a significant decrease in MAP and a significantly lower Aldrete score compared to all other groups. No haemodynamic or sedative adverse events were observed in the nefopam-treated patients. The results of our study indicate that nefopam (0.2 mg x kg(-1)) is superior to clonidine (1.5 microg x kg(-1)) in the prophylaxis of postanaesthetic shivering and not accompanied by sedative or haemodynamic side-effects.

Prise en charge des douleurs aiguës en médecine ambulatoire

An emergency. When treating a patient, relief of any acute pain is a priority. Such pain should be treated as an emergency, rapidly and effectively. Assessment is the first step Pain is a subjective phenomenon. Assessment of its intensity is the first step to its management. Regarding treatment The molecules that can be used for the treatment of acute pain in ambulatory patients can be classified into two categories, co-analgesics (antispasmodics and non-steroidal antiinflammatories) and pure analgesics classified by the WHO into three grades, although this classification presents certain limits. Nefopam is a central analgesic, with non-opiate action and, because of this inscribed by the WHO in the first grade, but with an analgesic capacity that corresponds to the substances of grade II analgesics. Its efficacy relies on medullar and/or supramedullar mechanisms. Via intramuscular injection The delay before action is of around 10 to 20 minutes and lasts for around 6 hours. The advantages of intramuscular nefopam are its analgesic capacity, its simplicity of use and its tolerance. The indications In ambulatory patients, Acupan is administered during acute arthritic pain, post-trauma and dental pain, renal colic, extremely severe migraine and headaches, dysmenorrhoea, and intense spasmodic colic.

The Median Effective Dose of Nefopam and Morphine Administered Intravenously for Postoperative Pain After Minor Surgery: A Prospective Randomized Double-Blinded Isobolographic Study of Their Analgesic Action

The aim of this study was to characterize the nature of analgesic interaction between nefopam and morphine administered i.v. for postoperative pain after minor surgery. To do so, we defined the median effective analgesic dose (ED(50)) for each drug and also the median ED(50) of their combination and compared them using the isobolographic method. Determination of median effective doses was performed by the up-and-down sequential drug administration in a two-stage study. First, in a prospective, randomized, double-blinded study, we enrolled 60 patients with mild to moderate pain after minor surgery; this was followed by an open study enrolling 30 patients. The end-point was a pain score less than 3 on a Numerical Pain Scale (0-10). Initial doses were 16 mg in group N, 5 mg in group M, and 7.5 mg of N combined with 2.5 mg of M in group N+M. The testing interval was 2 mg in group N, 1 mg in group M, and 1.5 mg of N combined with 0.5 mg of M in group N+M. ED(50) (95% confidence interval) was 5 mg (4-6 mg) for morphine, 18 mg (16-18 mg) for nefopam, and 4 mg (3.5-4.5 mg) with 12 mg (10.5-13.5 mg) for the combination of morphine and nefopam administered at a 3:1 dose ratio. Isobolographic analysis demonstrated a significant infra-additive interaction. The incidence of side effects did not differ significantly among morphine, nefopam, and their combination. These findings suggest that the combination of nefopam and morphine does not offer any advantage compared to each drug administered i.v. or alone after minor surgery. This study is the first to define the ED(50) of nefopam and morphine in postoperative patients. In conclusion, the addition of nefopam has a morphine-sparing effect, but the combination is infra-additive.

IMPLICATIONS

Pharmacologic interaction between nefopam and morphine shows infra-additivity but their combination may be clinically useful as morphine consumption is decreased in postoperative patients.

Effect of route of administration on the pharmacokinetic behavior of enantiomers of nefopam and desmethylnefopam

Nefopam hydrochloride is a non-narcotic analgesic used parenterally and orally as a racemic mixture for the relief of postoperative pain. However, no information is presently available on the oral kinetics of (+) and (-) nefopam in humans. Also, nefopam is metabolized by N-demethylation but it is not known whether the desmethylnefopam enantiomers (DES1 and DES2) are present in plasma following intravenous (I.V.) or oral administration of parent drug. To address these issues, 24 healthy white male subjects received two treatments using a double-blind, placebo-controlled crossover design: oral administration of 20 mg nefopam hydrochloride solution or a placebo solution on a sugar cube, simultaneously with a continuous infusion of 20 mg nefopam hydrochloride or placebo infusion. A chiral assay using LC-MS was developed for the simultaneous determination of both enantiomers of the parent drug and its metabolite in plasma and urine. Following I.V. administration, the kinetics of (+) and (-) nefopam could be fitted to a bi-exponential equation but exhibited no stereoselectivity. Both enantiomers had large clearances (53.7 and 57.5 L/hr) and volumes of distribution (390 and 381 L) and half-lives around 5 hours. Following oral administration, (+) and (-) nefopam were rapidly absorbed with bioavailabilities of 44% and 42%, respectively, probably due to a first-pass effect. After I.V. administration, the enantiomers of desmethylnefopam exhibited lower concentrations and longer half-lives (20.0 h for DES1 and 25.3 h for DES2) relative to nefopam enantiomers. Following oral administration, desmethylnefopam enantiomers' plasma concentrations peaked earlier and higher than after I.V. administration (P < 0.05). Following I.V. and oral administration, desmethylnefopam enantiomers showed stereoselectivity in AUC and Cmax values. Urinary excretion of parent and metabolite enantiomers was less than 5% of dose. This study shows that desmethylnefopam enantiomers can contribute to the analgesic effect of racemic nefopam only when it is administered orally.

Fatal overdosage with nefopam (Acupan)

This paper presents a fatality due to massive, intravenous self-administration of nefopam (Acupan), a non-opiate central analgesic, in a 37-year-old female. Nefopam was measured in various postmortem samples by means of high-pressure liquid chromatography coupled to mass spectrometry via an ionspray interface. Heart blood concentration was 4.38 microg/mL and exceeded by approximately 30 times the highest therapeutic levels with the usual reservations concerning possible postmortem redistribution. This is only the third case of death following nefopam overdose reported in the literature.

Managing postoperative pain

The postoperative course of a patient can be complicated by events such as pain, nausea and vomiting. These in themselves can have a significant impact upon morbidity and even survival. This article outlines key points to minimize such adverse outcomes.

[The use of Oxadol in tablet form for the treatment of chronic pain syndrome in late-stage cancer patients]

Chronic pain management with tablets of oxadol, a non-narcotic central-action analgetic, was studied in 30 patients, focusing on combinations with "basic" drugs of the opiate and opioid group. Combined administration of tramal and oxadol for moderate pain relief raised the analgesic effect and improved certain parameters of quality of life. Possible side-effects and indications in cases of well-advanced tumor were established.

[Postoperative oxadol analgesia in oncologic patients]

Oxadol (nefopam hydrochloride), a central analgesic, was used for postoperative pain relief in patients operated on the abdominal and pelvic organs for cancer. The analgesic effect of oxadol was sufficient for arresting moderate postoperative pain. Although the drug exerts rather many side effects, none of them notably deteriorated the clinical status of patients.

Control of post anaesthetic shivering with nefopam hydrochloride in mildly hypothermic patients after neurosurgery

Postoperative shivering may be prevented by maintaining normothermia intraoperatively or it may be treated using specific drugs. The aim of this study was to compare the efficacy of nefopam hydrochloride (nefopam) to that of clonidine and meperidine in patients undergoing elective neurosurgical procedures. Three groups of patients were included in the study. Patients in group A (60) received i.v., at random, 20 mg of nefopam, 50 mg of meperidine or 150 micrograms of clonidine in the immediate postoperative period. The incidence of shivering and the time at which shivering ceased were noted, along with central temperature and main haemodynamic changes. Group B (20) received i.v., at random, either 10 mg of nefopam or saline before awakening from anaesthesia. The effects of nefopam on central temperature, oxygen consumption (Vo2), carbon dioxide production (VcO2), basal metabolic rate (BMR) and energy expenditure (EE) were investigated. Group C (10) received i.v. 20 mg of nefopam during surgery: cerebrospinal fluid pressure (CSFP), cerebral perfusion pressure (CPP) and electroencephalogram (EEG) were monitored. In group A nefopam stopped shivering in 95% of patients when compared to meperidine and clonidine, which were effective in 32% and 40% of patients respectively. In group B, only 10% of patients receiving nefopam had postoperative shivering, Vo2, VcO2 and EE were significantly lower in patients treated with nefopam than those in the control group. No changes in CSFP, CPP or EEG were observed in group C. In conclusion, nefopam seems to be more effective than clonidine or meperidine in quickly suppressing shivering, without producing significant adverse reactions.

[The treatment of postoperative shivering with nefopam hydrochloride]

After having considered the physiopathological mechanism of shivering, the authors have estimated in a randomised study the effects of the resolution of shivering by nefopam hydrochloride. This drug a dose of 0.20 mg/kg resolved the symptoms in 100% of cases and the placebo hasn't resolved a case so that case it also obtained the same effects. The authors have proved the efficacy of the nefopam hydrochloride in the control of postoperative shivering in the recommended dose.

Postoperative nefopam and diclofenac. Evaluation of their morphine-sparing effect after upper abdominal surgery

The aim of the study was to assess the relative morphine-sparing effects of nefopam and diclofenac when used singly or in combination after upper abdominal surgery. Eighty-four patients of ASA grade 1 or 2 were allocated randomly to one of three groups. Group A received nefopam 20 mg by intramuscular injection 6 hourly after surgery for the 24-hour study period. Group B received diclofenac 75 mg 12-hourly and placebo injections at 6 and 18 hours after surgery. Group C received both 6-hourly nefopam and 12-hourly diclofenac. Supplemental analgesia was given on demand via a patient-controlled analgesia system which delivered intravenous morphine. Morphine requirements in the diclofenac group were significantly lower than in either of the other groups (p less than 0.01). Patients who received the combination of nefopam and diclofenac required significantly less morphine than those who received nefopam alone (p less than 0.01). Pain scores assessed 6 hours after surgery were significantly lower in the diclofenac and combination groups compared with the nefopam group (p less than 0.01).

[Infusion therapy of acute vertebragenic pain syndrome]

In the course of a double blind study 67 patients with acute vertebragenic pain syndromes have been treated with 3 infusion solutions, which only differed from each other by the analgetic component. Nefopam as an analgeticum showed a clearly prolonged effect and a quicker analgetic effect. As far as pains which occurred during a resting period and pains which occurred during a movement were concerned no differences in the effect were observed. Patients treated with Nefo-Dolpasse showed a smaller rate of side effects than those treated with comparable solutions.

[Valium-Acupan combination--its value at an isolated health center]

Twelve anaesthesias of the diazo-analgesia type have been carried out using a combination of two non depressive analgesics: a narcotic one and a powerful central one. These interventions are classified; used technique is described and results are commented on. Indications are not too painful quick surgical acts performed on patients with an empty stomach.

The need for analgesic cover after ENT surgery--comparison of nefopam and papaveretum

Intra-operative intramuscular injections of either papaveretum 0.3 mg/kg or nefopam 0.4 mg/kg were given to alternate patients to promote smooth emergence from ENT anaesthesia in a consecutive series of 40 children. Observations over a period of 30 minutes following completion of surgery showed that emergence was satisfactory in 19 out of 20 children given papaveretum, and in 15 out of 20 children given nefopam. The study confirms that this indication for papaveretum is justifiably popular and that nefopam is a useful alternative mainly because it does not cause respiratory depression. There are no previous reports of the use of nefopam in children.

Quantitative determination of nefopam in human plasma, saliva and cerebrospinal fluid by gas-liquid chromatography using a nitrogen-selective detector

A sensitive and selective gas-liquid chromatographic method for the determination of nefopam in human plasma, saliva and cerebrospinal fluid has been developed. The method includes the selective extraction of nefopam and the internal standard, orphenadrine, from biological fluids by a double extraction procedure. The extracted nefopam and internal standard are analyzed by a gas chromatograph equipped with a 3% OV-17 glass column and a nitrogen-phosphorus flame ionization detector (NPFID) operated in the nitrogen mode. The detector provides the needed high sensitivity and also selectivity due to the inherent characteristics of NPFID to discriminate against non-nitrogen containing materials. Five nanograms nefopam per ml plasma or saliva are routinely quantitated with a 1-ml sample or as little as 2 ng per ml cerebrospinal fluid with a 3-ml sample. The intra-day reproducibilities, expressed as the relative standard deviation, are 5, 2 and 3% at 10, 35 and 75 ng/ml plasma levels, respectively. The accuracies expressed by relative error at these levels are 12, -4 and -2%, respectively. The inter-day reproducibility is demonstrated by the small relative standard, deviation, 2%, of the slopes from ten plasma standard curves run on ten different days. In various clinical studies in humans the method has been successfully applied to the study of single-dose pharmacokinetics of nefopam and the monitoring of nefopam concentrations in saliva and cerebrospinal fluids.

Nefopam: a review of its pharmacological properties and therapeutic efficacy

Nefopam is a non-narcotic analgesic not structurally related to other analgesic drugs. It is effective by the oral and parenteral routes, and when appropriate dose ratios were compared in short term studies it was shown to produce analgesia comparable to that with the oral analgesics aspirin, dextropropoxyphene and pentazocine, as well as that with 'moderate' doses of parenteral morphine, pethidine and pentazocine. However, when 'higher' dose ratios were compared, morphine and pethidine were usually more effective than nefopam, possibly due to a 'ceiling effect' for analgesia which may occur with higher doses of nefopam, as with other simple analgesics. Although a few patients with chronic pain have received nefopam for several weeks, further studies are needed to clarify its continued effectiveness and safety when used over long periods. In most patients nefopam has been relatively well tolerated, the most frequent side effects being sweating, nausea and in some studies sedation.

Comparison of the analgesic dose-effect relationships of nefopam and oxycodone in postoperative pain

The analgesic dose-effect relationship of nefopam was compared in a double-blind randomised trial with that of oxycodone in immediate postoperative pain. Nefopam 15 mg or oxycodone 4 mg was given every 10 min i.v. (maximum six times) to patients in pain after upper abdominal surgery until their wound pain (scored 0-3) disappeared. The mean pain intensity (PI), initially 2.2 in both groups, descreased by approximately the same extent for up to two doses in both groups (to 1.5 after nefopam 30 mg and to 1.1 after oxycodone 8 mg). Thereafter PI was significantly less in the oxycodone group and diminished almost linearily to 0.1 after the sixth dose (24 mg). In the nefopam group, the PI score fell to 1.1 after the fourth dose (60 mg). This seemed to be the "ceiling" effect since additional doses up to 90 mg did not result in greater pain relief. In the oxycodone group, only two patients (12%) needed maximal dosage (6 x 4 mg), one of them requiring 32 mg of oxycodone. In the nefopam group, 12 patients (75%) needed further pain relief after the maximal dosage (6 x 15 mg). In these patients, oxycodone (maximally 16 mg) gave satisfactory analgesia. Drowsiness and a decrease in the respiratory rate were the principal side-effects of oxycodone, whereas tachycardia, restlessness, sweating and nausea were more frequent after nefopam.

Nefopam in postoperative pain

Three comparable groups of surgical patients were given nefopam 0.2 mg kg-1 or 0.4 mg kg-1 or morphine 0.15 mg kg-1 for pain relief after operation. Nefopam 0.4 mg kg-1 was equi-analgesic with morphine 0.15 mg kg-1 and produced no obvious cardiovascular or respiratory side-effects.

Oral nefopam and aspirin

Analgesia through nefopam (30 mg, 60 mg, 90 mg), aspirin (325 mg, 650 mg), and placebo were compared in 122 hospitalized patients with moderate to severe postoperative, fracture, or other somatic pain. A double-blind noncrossover study design was used, and patients were evaluated for pain intensity and pain relief over a 6-hr period. Based on sum of pain intensity differences (SPID) scores, treatment effects were consistent and indicative of good dose response to both active medications. Pain relief scores were more variable but were generally in accordance with SPID values. Time-effect curves were similar. Estimated relative potency of nefopam to aspirin was 10.4 with a 95% confidence interval of 6.3 to 20.8 for SPID, indicating that the analgesic potency of nefopam, 60 mg, was equivalent to that of aspirin, 650 mg. Side effects were minimal.

Comparison of nefopam and pethidine in postoperative pain

A double-blind, between-patient, two-dose comparison was comparison was performed with pethidine and nefopam in 100 subjects, the majority of whom were recovering from upper abdominal surgery. Either 15 or 30 mg of nefopam or 50 or 100 mg of pethidine were given by i.m. injection in a random order. All assessments were made by the same observer on the first day after operation, at least 4 h after the previous analgesic injection. Nefopam 15 mg was equipotent with pethidine 50 mg, peak analgesia being achieved 1 h after the i.m. injection. Pethidine 100 mg provided significantly better pain relief than nefopam 30 mg, the latter being not more effective than nefopam 15 mg apart from the duration of analgesia which was longer. The incidence of nausea and vomiting was similar after both drugs. Sweating and tachycardia were observed more frequently after nefopam, whereas sedative side-effects were more common after pethidine.