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The vasorelaxant effect of dipyrone on an experimental cerebral vasospasm model in rabbits.

Cerebral vasospasm is an important clinical phenomenon associated with a high mortality rate and therefore any promising findings in the laboratory deserve assessment in clinical practice. Dipyrone (Metamizol) has been in clinical use for its non-narcotic analgesic effect since 1922. In addition to its analgesic effect, dipyrone has been shown to possess spasmolitic activity in various smooth muscle organs. In our recent study, it was shown that dipyrone also has a relaxing effect in vascular smooth muscle preparations and that the smooth muscle relaxing effect on the rabbit thoracic aorta was produced by one of dipyrone's spontaneous degradation products. The present study was designed to examine the possible effects of dipyrone on the rabbit basilar artery in a model of cerebral vasospasm. Dipyrone was shown to have a clear spasmolitic effect in the rabbit basilar artery vasospasm produced by an intracisternal injection of autologous blood. This effect was apparent with either local or intravenous administration of dipyrone. These data suggest that dipyrone is potentially useful in the treatment of patients suffering from cerebral vasospasm in combination with other agents or alone.

Animals↗

Endoscopic assessment of the effects of dipyrone (metamizol) in comparison to paracetamol and placebo on the gastric and duodenal mucosa of healthy adult volunteers.

The potentially damaging gastric and duodenal effects of dipyrone, a nonnarcotic analgesic agent, were evaluated in three phases in comparison to placebo and paracetamol. Three groups of 12 healthy adult volunteers were treated in a double-blind study, according to a cross-over, randomization sequence, using the double-dummy technique, for two 15-day periods, with dipyrone 3 g/day and placebo (group I), dipyrone 1.5 g/day and placebo (group II), and dipyrone 1.5 g/day and paracetamol 1.5 g/day (group III). An esophagogastroduodenoscopy was performed at the beginning and end of each treatment period. In the first treatment group, grade-3 and 4 mucosal lesions were found after dipyrone administration (3 g/day) in 3 of 12 (25%) subjects (multiple antral erosions, gastric ulcer and duodenal ulcer, 1 case each), whereas grade-2 mucosal lesions (antral erosions) were detected in 1 of 12 cases (8%) after the corresponding placebo treatment. The difference between the two treatments, however, was not statistically significant (p > 0.05). Only in the gastric ulcer case were subjective symptoms reported (feeling of hunger). At the 1.5-g/day dose (groups II and III), dipyrone produced no gastroduodenal lesions, the endoscopic results showing no appreciable difference between dipyrone and either placebo (p = 0.54) or paracetamol (p = 0.99). No subjective symptoms were reported in any of these subjects. Dipyrone, administered for 2 weeks, has effects on the gastric and duodenal mucosa comparable to those of paracetamol and placebo, though noticeable damage is detectable at a dosage of 3 g/day.

Acetaminophen↗

Intravenous dipyrone for the acute treatment of episodic tension-type headache: a randomized, placebo-controlled, double-blind study.

Acute headaches are responsible for a significant percentage of the case load at primary care units and emergency rooms in Brazil. Dipyrone (metamizol) is easily available in these settings, being the most frequently used drug. We conducted a randomized, placebo-controlled, double-blind study to assess the effect of dipyrone in the acute treatment of episodic tension-type headache. Sixty patients were randomized to receive placebo (intravenous injection of 10 ml saline) or 1 g dipyrone in 10 ml saline. We used seven parameters of analgesic evaluation. The patients receiving dipyrone showed a statistically significant improvement (P<0.05) of pain compared to placebo up to 30 min after drug administration. The therapeutic gain was 30% in 30 min and 40% in 60 min. The number of patients needed to be treated for at least one to have benefit was 3.3 in 30 min and 2.2 in 60 min. There were statistically significant reductions in the recurrence (dipyrone = 25%, placebo = 50%) and use of rescue medication (dipyrone = 20%, placebo = 47.6%) for the dipyrone group. Intravenous dipyrone is an effective drug for the relief of pain in tension-type headache and its use is justified in the emergency room setting.

Analgesics↗

The opiate-sparing effect of dipyrone in post-operative pain therapy with morphine using a patient-controlled analgesic system.

OBJECTIVE: To determine whether dipyrone has an opiate-sparing effect in post-operative pain therapy compared with placebo during patient-controlled morphine therapy (PCA) and to compare the effects on analgesia and respiratory and coagulation parameters. DESIGN: Randomized, observer-blind, parallel-group, placebo-controlled study. SETTING: Surgical intensive care unit of a university hospital. PATIENTS: 106 adult patients who were to undergo abdominal or urological surgery under 90-min standardized inhalational anaesthesia were entered and 103 were included in the efficacy analysis (53 on dipyrone, 50 on placebo). INTERVENTIONS: Preprogrammed PCA (0.03 mg morphine/kg per bolus) with either dipyrone (initially 2.0 g i.v. and 1.0 g/2 ml i.v. at 4, 8 and 16 h) or placebo (saline). MEASUREMENTS AND RESULTS: Cumulative morphine consumption was calculated automatically during PCA. Pain intensity and pain relief and the investigator's global assessments of efficacy and tolerability were recorded on five-point verbal rating scales. Vital signs, standard laboratory parameters, respiratory rate, partial pressure of carbon dioxide (PCO2) and of oxygen, partial thromboplastin time (PTT) and Quick values were recorded. Total consumption of opiates in the dipyrone group (median 31.6 mg) was significantly less (p = 0.00015) than in the placebo group (median 50.3 mg), while pain relief (area under the curve) AUC was the same for both PCA+dipyrone (median 4.1) and PCA+placebo (median 3.9). Global assessment of efficacy was good to excellent in more than 90% of cases in both groups. Vital signs, respiratory rate, PCO2, PTT and Quick did not differ between groups. Adverse events were mainly nausea and/or vomiting (dipyrone, n = 4; placebo, n = 1); 1 patient in the placebo group had bradycardia. Three serious adverse events were unrelated to study medication. In 1 patient, the PCA programme malfunctioned and had to be changed. CONCLUSIONS: Concomitant administration of dipyrone with on-demand morphine (PCA) reduces opiate consumption while maintaining post-operative pain relief with a low incidence of side-effects.

Adult↗

The effect of short-term dipyrone administration on cyclosporin pharmacokinetics.

BACKGROUND: A large number of drugs have been shown to affect the metabolism of cyclosporin A (CSA) and, since cyclosporin is characterized by a narrow therapeutic range, the consequences of such drug interactions may often be of clinical importance. OBJECTIVE: To evaluate the effect of short-term administration of dipyrone on steady state CSA pharmacokinetics. METHODS: Six kidney- and two heart-transplanted patients on chronic CSA therapy participated in this study, which consisted of two 4-day study periods separated by 3-week washout periods. The patients received, in addition to their usual drugs, dipyrone 500 mg or placebo t.i.d., as identical-looking tablets, and the order of administration was randomized. CSA concentrations were measured in whole blood by means of radio-immunoassay (CYCLO-Trac SP) daily during the study periods and periodically over 24 h on the fourth study day. RESULTS: CSA concentrations over time were reduced after dipyrone (ANOVA, P < 0.01), but statistical significance was noted only at 2, 4, 5 and 10 h after drug intake (P < 0.05). Peak CSA concentration was not altered by dipyrone, but the time required to reach maximal concentration was longer with dipyrone treatment than with the placebo (3.8 +/- 2.6 h vs 2.1 +/- 0.6 h, P < 0.05). No consistent changes were noted for CSA trough level, elimination half-life and area under the concentration-time curve from 0 h to 12 h. Separate analysis of the kidney transplanted patients yielded similar results. CONCLUSIONS: Short-term administration of dipyrone is associated with a mild decrease in CSA blood concentration, which is most prominent in the first few hours after drug intake. In practice, no dose adjustment of CSA seems to be indicated during a short course of dipyrone treatment.

Adult↗

Endogenous opioids are involved in morphine and dipyrone analgesic potentiation in the tail flick test in rats.

The combined administration of low doses of opiates with non-steroidal anti-inflammatory drugs can produce additive or supra-additive analgesic effects while reducing unwanted side effects. We have recently reported that co-administration of morphine with dipyrone (metamizol) produces analgesic potentiation both in naïve and in morphine-tolerant rats. The purpose of this work was to determine the role of opioids on the acute potentiation observed between morphine and dipyrone i.v. in the rat tail flick test. To do this, two experiments were done. In the first one, naloxone was administered 10 min before morphine (3.1 mg/kg), dipyrone (600 mg/kg) or their combination at the same doses. Control animals received saline instead of naloxone. In the second experiment, naloxone (or saline) was given 2 min after reaching the maximal peak effect with each individual analgesic treatment. When naloxone was i.v. administered prior to analgesics, it completely blocked morphine effects, partially prevented morphine/dipyrone antinociception and delayed dipyrone-induced nociception. At 3.1 mg/kg, naloxone produced an increased nociception. When naloxone was given after analgesics, it dose-dependently blocked the effects of morphine alone and in combination with dipyrone but with different potency in each case. As to dipyrone, naloxone delayed the time to antinociceptive peak effect. Taken together, these results support the notion that endogenous opioids are involved in the analgesic potentiation observed with the combination of morphine plus dipyrone.

Analgesics, Opioid↗

Does dipyrone have any effect on respiratory function in COPD patients?

OBJECTIVE: Dipyrone (Novalgin) is an effective analgesic, antipyretic agent also with spasmolytic effects on various types of smooth muscles. It has recently been reported that dipyrone relaxes tracheal smooth muscle of guinea pig. In this present study, we aimed to investigate whether this and previously reported in vitro results have any consequences on the respiratory function of normal healthy volunteers and chronic obstructive pulmonary disease (COPD) patients. METHODS: In this one-centered, non-randomized, non-comparative, open labelled study, 15 normal healthy volunteers and 15 stable COPD patients, with partially reversible bronchospasm, diagnosed according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria were enrolled in the study at the time they had any indication of dipyrone use. The spirometric tests were performed by a portable notebook and Medikro Spiro2000 spirometry programme-software 1.6 version, before 30, 60, 90, and 120 min after 20 mg/kg of orally dipyrone intake. Groups were compared with the General Linear Model Repeated Measures analysis of variance. RESULTS: None of the spirometric parameters evaluated showed any significant differences when compared with the baseline values in both groups. CONCLUSION: While dipyrone had no bronchodilator effects on either COPD patients or normal volunteers, it also did not impair the spirometric parameters. Since COPD is a disease characterized by a progressive and largely irreversible airflow limitation, dipyrone has no observable bronchodilator effect. However, since dipyrone does not impair the pulmonary function, it can be used safely in COPD patients when there is an indication.

Adult↗

Morphine and dipyrone co-administration delays tolerance development and potentiates antinociception.

This work analyses the time course of tolerance development and antinociceptive potentiation throughout repeated co-administration of morphine (an opioid receptor agonist) plus dipyrone (a non-steroidal anti-inflammatory drug) in the tail-flick test. Male Wistar rats were i.v. injected with morphine (3.1 mg/kg), dipyrone (600 mg/kg) or the combination morphine/dipyrone twice a day for 5 days. Dipyrone produced antinociceptive effects with a trend towards tolerance development at the end of the treatment. Morphine was initially effective, but complete tolerance developed after its fifth administration. The combination of morphine plus dipyrone produced a significant potentiation and longer duration of antinociceptive effects. The antinociceptive efficacy of morphine and dipyrone co-administration gradually decreased after the sixth injection. An additional group of rats treated with dipyrone for 11 days developed complete tolerance after the 19th administration. These data suggest that repeated co-administration of morphine plus dipyrone results in a delay of tolerance development and in a potentiation of their individual antinociceptive effects.

Analgesics↗

Efficacy and safety of dipyrone versus tramadol in the management of pain after hysterectomy: a randomized, double-blind, multicenter study.

BACKGROUND AND OBJECTIVES: We assessed the efficacy and safety of dipyrone in comparison with tramadol in the relief of early postoperative pain following abdominal hysterectomy. METHODS: A total of 151 women between 18 and 60 years of age undergoing abdominal hysterectomy during general anesthesia participated in a randomized, double-blind, controlled, multicenter study. Seventy-three patients received dipyrone and 78 received tramadol. Patients received an intravenous loading dose of the study drug immediately after operation followed by intravenous (IV) maintenance infusion and IV on-demand boluses up to a maximum number of predetermined doses/day of 8 g dipyrone and 500 mg tramadol. The duration of the study was 24 hours. RESULTS: The mean (SD) number of boluses in the dipyrone group was 3.8 (2.4) and 3.5 (2.5) in the tramadol group (95% confidence interval, -0.455 to 1.175), and the percentage of patients requiring rescue IV morphine (dipyrone 26.9%, tramadol 26.8%) was not statistically significant. Other analgesic efficacy parameters, such as pain intensity differences, sum of pain intensity differences, pain relief assessed by the patient, or patients who required the maximum number of demand doses, were not different between treatment groups. A significantly higher percentage of adverse gastrointestinal effects was found in patients given tramadol (42.1%) than in patients given dipyrone (20.2%) (P <.05). Also, a significantly higher number of tramadol-treated patients required ondansetron to control nausea and vomiting at 1 hour (19% v 7%), 2 hours (26% v 11%), and 24 hours (46% v 29%) (P <.05) after surgery. Patients and the investigators reported similar tolerability for both study arms. CONCLUSIONS: Dipyrone and tramadol showed similar efficacy for early pain relief after abdominal hysterectomy. Nausea and vomiting, possibly caused by the tramadol, occurred more frequently in those patients. In this group, the need of the antiemetic drug ondansetron was also higher.

Adolescent↗

Dipyrone overdose.

BACKGROUND: Dipyrone is a pyrazolone derivative used as an analgesic and antipyretic. Agranulocytosis, dipyrone's most serious and potentially fatal adverse effect, has led to its withdrawal in several countries. However, agranulocytosis is subject to geographical variability, ratio with at risks ranging from 0.8-23.7. In many countries dipyrone is still widely used in adults and children and even as an over-the-counter (OTC) preparation. Information on the effects of dipyrone overdose is scanty. OBJECTIVE: To determine the demographic and clinical characteristics of dipyrone overdose. METHODS: Retrospective review of prospectively collected poison center data on acute exposure to dipyrone over a three-year period. The data were subjected to descriptive analysis. Mann-Whitney test and Chi-square analysis were performed where relevant. RESULTS: A total of 243 records met the inclusion and exclusion criteria. Median age was 17y (4m-83y), median amount 5 g (250 mg-45 g), and median time to consultation was 2 h (5 min-48 h). Toxic events (49) occurred in 39 (16%) patients; 57% of these were gastrointestinal and all were mild. Time to consultation was longer in the symptomatic patients (4 h vs. 1.5 h, respectively, p=0.001) and in children (8 h vs. 3.5 h in adults). Suicidal patients ingested significantly larger amounts (8 g vs. 3.7 g, respectively, p=0.001), as did patients with gastrointestinal symptomatology (7.5 g vs. 5 g in asymptomatics, p=0.001). No agranulocytosis was reported. DISCUSSION: Dipyrone overdose is associated with mild, mainly gastrointestinal toxicity; this was noted at a median dose of 7.5 g. Early gastrointestinal decontamination may have prevented toxicity. The suggested treatment includes gastrointestinal decontamination (if <1 h since ingestion) and supportive measures.

Adolescent↗

The anti-inflammatory drugs phenylbutazone and dipyrone in the treatment of field cases of bovine mastitis.

The efficacy of phenylbutazone vs. dipyrone for the treatment of acute clinical mastitis were compared in a clinical trial. All cows were treated with 20 g sulfadiazine and 4 g trimethoprim i.m. upon diagnosis and half dosage once daily thereafter. In addition, the NSAIDs treated cows received once daily either 4 g phenylbutazone or 20 g dipyrone i.m. for the duration of the antimicrobial therapy. In all treatment groups the major causative organisms were coliforms. Recovery rates for the controls, the phenylbutazone and dipyrone treatment groups were 81.8%, 89.4% and 86.6%, respectively. Recovery was evaluated by the logistic regression analysis, the odds ratios (OR) and their 95% confidence interval (CI) of treatment success for phenylbutazone and dipyrone treatments relative to the control treatment were calculated. Odds ratio of recovery was high for phenylbutazone (OR = 2.42; CI = 0.98-5.96; P = 0.054) as well as for dipyrone (OR = 1.71; CI = 0.98-3.00; P = 0.060), demonstrating a strong trend towards improved recovery in NSAID groups. The odds of treatment failure for the phenylbutazone group relative to the dipyrone group was 0.71 with 95% CI of 0.28-1.78. Clearly no significant difference could be demonstrated between phenylbutazone and dipyrone in this field trial.

Animals↗

Differential effect of acetylsalicylic acid and dipyrone on prostaglandin production in human fibroblast cultures.

Human skin fibroblasts incubated with arachidonic acid in culture show basal release of prostaglandins. They produce the same prostaglandins after stimulation with bradykinin. Basal release of prostaglandins I2 (6-oxo-PGF1 alpha), F2 alpha and E2 is inhibited dose-dependently by both acetylsalicylic acid (ASA) and dipyrone (P less than 0.05). The examined dose-range was 10(-7) to 10(-4) M for both drugs. During the first 5 min after removal of the drugs from the incubation medium, bradykinin-stimulated release remains dose-dependently inhibited (P less than 0.001) in ASA-, but not in dipyrone-treated cultures. The difference between the effects of ASA and of dipyrone is highly significant (P less than 0.0001), whereas the dipyrone-treated cultures are not different from controls. The findings are consistent with cyclo-oxygenase inhibition by ASA as well as by dipyrone. However, the data demonstrate rapid reversibility of the effect of dipyrone. This suggests that in contrast to ASA, dipyrone does not inhibit cyclo-oxygenase by binding covalently to the enzyme.

Aminopyrine↗

Effect of the GABAB agonist baclofen on dipyrone-induced delayed gastric emptying in rats.

Dipyrone administered intravenously (iv) or intracerebroventricularly (icv) delays gastric emptying (GE) in rats. Gamma-aminobutyric acid (GABA) is the most potent inhibitory neurotransmitter of the central nervous system. The objective of the present study was to determine the effect of icv baclofen, a GABAB receptor agonist, on delayed GE induced by dipyrone. Adult male Wistar rats received a saline test meal containing phenol red as a marker. GE was indirectly evaluated by determining the percent of gastric retention (%GR) of the meal 10 min after orogastric administration. In the first experiment, the animals were injected iv with vehicle (Civ) or 80 mg/kg (240 micromol/kg) dipyrone (Dpiv), followed by icv injection of 10 microl vehicle (bac0), or 0.5 (bac0.5), 1 (bac1) or 2 microg (bac2) baclofen. In the second experiment, the animals were injected icv with 5 microl vehicle (Cicv) or an equal volume of a solution containing 4 micromol (1333.2 microg) dipyrone (Dpicv), followed by 5 microl vehicle (bac0) or 1 microg baclofen (bac1). GE was determined 10 min after icv injection. There was no significant difference between control animals from one experiment to another concerning GR values. Baclofen at the doses of 1 and 2 microg significantly reduced mean %GR induced by iv dipyrone (Dpivbac1 = 35.9% and Dpivbac2 = 26.9% vs Dpivbac0 = 51.8%). Similarly, baclofen significantly reduced the effect of dipyrone injected icv (mean %GR: Dpicvbac1 = 30.4% vs Dpicvbac0 = 54.2%). The present results suggest that dipyrone induces delayed GE through a route in the central nervous system that is blocked by the activation of GABAB receptors.

Animals↗

A population-based case-control teratologic study of oral dipyrone treatment during pregnancy.

OBJECTIVE: To study the possible human teratogenic effect of oral dipyrone, an antipyretic and analgesic drug treatment during pregnancy. DESIGN AND SETTING: The analysis of cases with different congenital abnormalities and their matched population controls without congenital abnormalities, in addition to a comparison between cases and malformation controls (Down's syndrome) in the population-based, large data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996. STUDY PARTICIPANTS: 22 843 neonates or fetuses with congenital abnormalities (cases), 38 151 matched newborns without congenital abnormalities (population controls) and 834 neonates or fetuses with Down's syndrome (malformation controls). MAIN OUTCOME MEASURES: 25 congenital abnormality groups. RESULTS: 1382 (6%) cases, 1911 (5%) population controls and 74 (8.9%) malformation controls were born to mothers treated with dipyrone during pregnancy. The case-matched population control analysis showed a higher rate of diaphragmatic defect (adjusted prevalence odds ratio [POR] 2.7; 95% CI 1.0, 6.8), cardiovascular malformations (POR 1.3; 95% CI 1.0, 1.7) and other isolated congenital abnormalities (POR 1.8; 95% CI 1.1, 2.9) after oral dipyrone treatment during the second and third months of gestation, i.e. in the critical period for most major congenital abnormalities. However, the evaluation of only medically recorded dipyrone use did not confirm these possible associations. The comparison of dipyrone treatment between 25 congenital abnormalities groups and malformation controls as the referent group also did not show any difference in the dipyrone use during the second and third months of gestation. CONCLUSIONS: The higher occurrence of dipyrone treatment in the case mothers compared with population control mothers can be explained by recall bias and/or chance. However, the higher rate of diaphragmatic congenital abnormalities can be considered as a signal and merits further investigation.

Abnormalities, Drug-Induced↗

Effect of dexamethasone and dipyrone on lingual and inferior alveolar nerve hypersensitivity following third molar extractions: preliminary report.

AIMS: To study the effect of dexamethazone and dipyrone on sensory changes in the innervation territories of the inferior alveolar, infraorbital, and lingual nerves caused by third molar extractions. METHODS: Fourteen patients (8 men and 6 women) were divided randomly into 2 groups. The first group received dipyrone preoperatively, while the second group received dipyrone and dexamethazone preoperatively. All patients in the study received a prophylactic preoperative dose of amoxicillin (500 mg) as well as dipyrone postoperatively. In all patients, a single mandibular third molar was removed, while in 2 patients the contralateral third molar was removed at a subsequent time. Electrical detection thresholds were assessed in the inferior alveolar, lingual, and infraorbital nerve regions prior to surgery and 2 and 8 days following surgery. The level of perioperative pain, difficulty of extraction, and distance of molar root apices from the inferior alveolar nerve canal were also assessed. RESULTS: Patients who received only dipyrone had significantly reduced lingual and inferior alveolar nerve electrical detection thresholds 2 days after surgery, which returned to nearly baseline values by the eighth day postoperatively. In patients who received dexamethasone, no significant reduction in the electrical detection threshold was found. CONCLUSION: Preoperative treatment with dexamethasone and dipyrone but not dipyrone alone prevents sensory hypersensitivity following third molar extraction.

Anti-Inflammatory Agents↗

Efficacy of two different intramuscular doses of dipyrone in acute renal colic. Cooperative Study Group.

A randomized multicenter clinical trial was designed to compare the efficacy and tolerance of two different intramuscular doses of dipyrone (1 g and 2 g) with those of the reference drug, diclofenac sodium (75 mg), in the treatment of acute renal colic. A total of 129 patients were included; 43 patients were alloted to receive dipyrone 1 g, 45 to dipyrone 2 g, and 41 to diclofenac. Evaluation of pain (100 mm visual analogue scale) was carried out at 10, 20, 30, 60 min and 2, 4 and 6 h after drug administration. There were no significant differences between the three groups in terms of pain relief in the first 60 min, but dipyrone 2 g provided significantly more pain relief than diclofenac and dipyrone 1 g from 60 min to 6 h after drug injection. It is concluded that dipyrone 2 g produced a longer lasting analgesic response than dipyrone 1 g in the treatment of renal colic.

Acute Disease↗

Double-blind study with dipyrone versus tramadol and butylscopolamine in acute renal colic pain.

To investigate the combined analgesic and spasmolytic effect of dipyrone, 104 patients suffering from "severe" or "excruciating" colic pain due to a confirmed calculus in the upper urinary tract were randomized to receive i.v. either 2.5 g dipyrone (36 patients), 100 mg tramadol (35 patients), or 20 mg butylscopolamine (33 patients) in a multicentre, observer-blind, parallel-group study conducted in 8 German centres. The three treatment groups were homogeneous when analyzed by age, sex, height, and baseline pain intensity. Dipyrone was significantly more effective than tramadol in reducing pain for the primary endpoint, pain intensity differences (PID) at 20, 30, and 50 min after drug administration, and was significantly more effective than butylscopolamine at 30 and 50 min for the secondary efficacy endpoint, pain intensity differences on a categorical scale. Dipyrone had the highest SPID0-2 h of the three drugs (P < 0.05). Only 5 patients receiving dipyrone needed "rescue" medication as compared with 13 patients given tramadol and 11 patients receiving butylscopolamine. Adverse events were observed in 4 patients receiving butylscopolamine and in 1 patient each given dipyrone and tramadol. "Distinct" pain relief as assessed on a visual analogue scale (VAS) is a reliable method of determining the onset of analgesic action in the colic pain model.

Acute Disease↗

Analgesic and antiinflammatory effects of dipyrone in rat adjuvant arthritis model.

Dipyrone, a pirazolone derivative, is a known analgesic drug with minor toxic effects associated with its administration. The aim of the present study was to determine the analgesic and antiinflammatory effects of dipyrone in a model of chronic inflammation (adjuvant-induced arthritis in rats). Hind-paw hyperalgesia was detected in arthritic rats from the 10th to the 16th day of observation. Edema development was maximum (twofold increase) at the 14th day of observation compared to control animals and reduced at the 16th day of observation. Dipyrone (1-50 mg/kg) dose-dependently reduced both hind-paw hyperalgesia and edema from arthritic rats. However, it was shown to be more potent as analgesic than antiinflammatory in the present model. In contrast, indomethacin (2 mg/kg) and dexamethasone (0.4 mg/kg) completely inhibited hind-paw hyperalgesia and edema development. Our results indicate that dipyrone reduced the hyperalgesia and edema in arthritic rats by a mechanism not involving release of prostaglandin-like substances. The possibility of dipyrone inducing analgesia in arthritic rats through a peripheral action supports the use of dipyrone as an alternative choice drug for the treatment of pain associated with arthritislike diseases in selected cases.

Analgesics↗