Site-specific effects of the nonsteroidal anti-inflammatory drug lysine clonixinate on rat brain opioid receptors

Intravenous lysine clonixinate for the acute treatment of severe migraine attacks: a double-blind, randomized, placebo-controlled study

BACKGROUND

Several nonsteroidal anti-inflammatory drugs (NSAIDs) have been shown to be effective in the treatment of migraine. However, few commercially available NSAIDs can be administered IV. Lysine clonixinate (LC), an NSAID derived from nicotinic acid, has been proved effective in various algesic syndromes (eg, renal colic, muscular pain, nerve compression, odontalgia). The oral formulation of LC has been shown to be effective in the treatment of migraine of moderate severity.

OBJECTIVE

The aim of this study was to assess the efficacy and tolerability of the IV formulation of LC in the treatment of severe migraine.

METHODS

This double-blind, randomized, placebo-controlled, prospective study enrolled patients with severe migraine (without aura) as defined by the criteria of the International Headache Society. When patients presented to a neurology hospital with an outpatient headache unit (Instituto de Neurologia Deolindo Couto, Rio de Janeiro, Brazil) with a severe migraine attack that had lasted <4 hours, they were randomized to 1 of 2 groups (IV placebo [25 mL of 0.9% saline] or IV LC [21 mL of 0.9% saline plus 4 mL of LC 200 mg]). Headache intensity and adverse effects (AEs) were assessed before (0 minute) and 30, 60, and 90 minutes after study drug administration. Rescue medication was available 2 hours after study drug administration, and its use was compared between groups.

RESULTS

Thirty-two patients (23 women, 9 men; mean [SD] age, 32 [2] years; range, 18-58 years) entered the study. Twenty-nine patients (21 women, 8 men; mean [SD] age, 32 [2] years; range, 18-56 years) completed the study. Three patients (all in the placebo group) did not complete the study (1 patient was unable to rate the pain severity after drug administration and 2 patients refused IV drug administration). Among study completers, 17 patients received LC and 12 placebo. At 30 minutes, 1 patient (8.3%) in the placebo group and 5 patients (29.4%) in the LC group were pain free; the between-group difference was not statistically significant. At 60 and 90 minutes, respectively, 3 (25.0%) and 5 (41.7%) patients in the placebo group and 12 (70.6%) and 14 (82.4%) patients in the LC group were pain free (P = 0.021 and P = 0.028 between groups at 60 and 90 minutes, respectively). Six patients (50.0%) in the placebo group and 1 patient (5.9%) in the LC group required rescue medication at 2 hours (P = 0.010 between groups). Three patients (25.0%) in the placebo group experienced AEs, including vomiting, dizziness, and malaise (1 patient [8.3%] each); 11 patients (64.7%) in the LC group experienced 1 AE, including burning pain at the injection site (5 patients [29.4%]), heartburn (4 patients [23.5%]), and dizziness and malaise (1 patient [5.9%] each) (P = 0.025).

CONCLUSIONS

NSAIDs administered by the IV route cannot be used routinely in an outpatient environment, although an attempt to improve drugs in this class is clearly justified. This study demonstrated that IV LC was effective and well tolerated in the treatment of severe migraine attacks. This finding differs from results with the oral formulation, which is effective only in migraine of moderate severity.

Flurbiprofen axetil enhances analgesic effect of fentanyl associated with increase in β-endorphin levels

PURPOSE

To examine the analgesic effect of preoperative administration of flurbiprofen axetil and that of postoperative administration of a combination of flurbiprofen axetil and fentanyl, as well as perioperative plasma β-endorphin (β-EP) levels in patients undergoing esophagectomy.

METHODS

Forty-five patients were randomly divided into three groups: group A: 100 mg flurbiprofen axetil preoperative, 10 μg/kg fentanyl + 10 ml placebo postoperative; group B: 100 mg flurbiprofen axetil preoperative, 10 μg/kg fentanyl + 100 mg flurbiprofen axetil postoperative; group C: 10 ml placebo preoperative, 10 μg/kg fentanyl + 10 ml placebo postoperative. Postoperative analgesia was achieved by intravenous infusion containing flurbiprofen axetil and/or fentanyl at 2.0 ml/h (total volume, 100 ml) using infusion pumps. The β-EP was measured at preanesthesia (T(1)), the end of surgery (T(2)), 24 h (T(3)), and 48 h (T(4)) after surgery. Visual analog scale scores (VAS) at T3, T4 (at rest), and rescue analgesic tramadol requirement was recorded.

RESULTS

The VAS of group B was significantly lower than group A and C (P < 0.01) at T(3) and T(4). The β-EP levels at T(2)-T(4) in group A did not differ significantly from those at T(1) (P > 0.05); however, the β-EP levels in group B at T(3)-T(4) increased significantly (P < 0.05), while those in group C increased at T(2) and decreased at T(4) (P < 0.05). The β-EP levels in group B at T(3) and T(4) were the highest as compared to its levels in groups A and C (P < 0.01). Tramadol consumption in group B was significantly lower than in groups A and C (P < 0.01).

CONCLUSION

These results show that flurbiprofen axetil enhances the analgesic effect of fentanyl associated with increase in β-EP levels.

Assuring that 1080 toxicosis in the red fox (Vulpes vulpes) is humane. II. Analgesic drugs produce better welfare outcomes

Fluoroacetic acid (1080) is a widely used vertebrate pesticide in Australia and New Zealand. In Australia it is used in meat baits as the primary method of control for the introduced red fox (Vulpes vulpes). Subsequent to the onset of initial signs, collapse and convulsions are associated with central nervous system disruptions where the animal is unresponsive to external stimuli, making an assessment of humaneness difficult. Prior to collapse and unconsciousness it would appear that there is potential for suffering to occur although its extent and nature during the entire toxicosis remains unclear. We investigated various formulations of 1080 with either analgesic or anxiolytic drugs in order to manage possible suffering experienced during 1080 poisoning of red foxes. Oral doses of 0.5 mg kg−1 1080 alone produced no visible signs for a mean of 205.3 min (±28 min, P < 0.05), but were lethal after signs that lasted a mean of 103 min (±16 min, P < 0.05). Combinations of 0.5 mg kg−1 1080 with either 10 mg kg−1 carprofen (CA), 0.4 mg kg−1 copper indomethacin (CI) or 10 mg kg−1 buspirone (BS) were assessed in pen trials and compared with a group that received 0.5 mg kg−1 1080 only and one that received the drug dose only. CI reduced the time between the onset of signs and death (P < 0.01) and CA reduced the overall intensity of activity from dosage to death (P < 0.05). A significant reduction in the incidence of retching during the onset of signs was observed in foxes that were coadministered CA (P < 0.05) or CI (P < 0.01) with 1080 compared with 1080 alone. The combination of BS and 1080 halved the mean activity from first signs to death, but was not statistically significant. In a separate trial, drug and 1080 combinations were delivered to penned foxes using an M-44 ejector. Neither 70 mg CA nor 2.8 mg CI appeared to affect the lethality of 1080 doses, although 70 mg BS produced a result that was equivocal and warrants further investigation. Coadministration of 70 mg diazepam was associated with the survival of six of nine foxes and suggests that there may be the potential for diazepam to act in the treatment of accidentally poisoned domestic dogs and this is discussed briefly. Given evidence for both central and peripheral analgesia, its potential to reduce the duration of signs and incidence of retching, CI shows immediate potential to be used with 1080 fox baits and to assist in delivering better welfare outcomes in fox control.

Lysine clonixinate versus dipyrone (metamizole) for the acute treatment of severe migraine attacks: a single-blind, randomized study

BACKGROUND AND OBJECTIVE: Nonsteroidal anti-inflammatory drugs (NSAID) are effective to treat migraine attacks. Lysine clonixinate (LC) and dipyrone (metamizol) have been proven effective to treat acute migraine. The aim of this study was to evaluate the efficacy and tolerability of the intravenous formulations of LC and dipyrone in the treatment of severe migraine attacks. METHOD: Thirty patients (28 women, 2 men), aged 18 to 48 years with migraine according the International Headache Society (IHS) (2004) were studied. The patients were randomized into 2 groups when presenting to an emergency department with a severe migraine attack. The study was single-blind. Headache intensity, nausea, photophobia and side effects were evaluated at 0, 30, 60 and 90 minutes after the drug administration. Rectal indomethacin as rescue medication (RM) was available after 2 hours and its use compared between groups. RESULTS: All patients completed the study. At 30 minutes, 0% of the dipyrone group 13% of the LC group were pain free (p=0.46). At 60 and 90 minutes, 2 (13%) and 5 (33%) patients from the dipyrone group and 11 (73%) and 13 (86.7%) patients from the LC group were pain free (p<0.001). At 60 minutes, significantly more patients from the LC group were nausea-free (p<0.001). Regarding photophobia, there were no differences between groups at 60 minutes (p=0.11). The use of RM at 2 hours did not differ among groups (p=0.50). Pain in the site of the injection was reported by more patients of the LC group compared to the dipyrone group (p<0.0001). CONCLUSION: LC is significantly superior to dipyrone in treating severe migraine attacks. LC promotes significantly more burning at the site of the injection.

Effect of meloxicam and butorphanol on minimum alveolar concentration of isoflurane in rabbits

OBJECTIVE

To determine the effects of meloxicam and butorphanol on minimum alveolar concentration of isoflurane (MAC(ISO)) in rabbits.

ANIMALS

10 healthy young adult female rabbits.

PROCEDURE

Rabbits were anesthetized with isoflurane on 3 occasions in a blinded, randomized complete block design to determine the MAC(ISO) associated with administration of meloxicam (0, 0.3, or 1.5 mg/kg, PO) and butorphanol (0.4 mg/kg, IV). The MAC(ISO) was determined by use of a paw clamp technique as the end-tidal concentration of isoflurane halfway between the values that allowed or inhibited purposeful movement. Rectal temperature, end-tidal CO2 concentration, heart rate, oxygen saturation, and arterial blood pressure were measured to evaluate cardiopulmonary function.

RESULTS

Mean +/- SE MAC(ISO) in saline (0.9% NaCl) solution-treated rabbits was 2.49 +/- 0.07% and was not significantly different from that associated with administration of meloxicam at 0.3 mg/kg (2.56 +/- 0.07%) or 1.5 mg/kg (2.66 +/- 0.07%). Butorphanol significantly reduced the MAC(ISO) to 2.30 +/- 0.07% when administered with saline solution alone, 2.27 +/- 0.07% when administered with 0.3 mg of meloxicam/kg, and 2.33 +/- 0.07% when administered with 1.5 mg of meloxicam/kg. The percentage reduction in MAC(ISO) was significantly greater for rabbits that received butorphanol and meloxicam at either dose, compared with butorphanol and saline solution.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that meloxicam does not have a direct isoflurane-sparing effect and does not interfere with the anesthetic-sparing effect of butorphanol in rabbits.

Distribution of G-protein-coupled receptor kinase (GRK) isoforms 2, 3, 5 and 6 mRNA in the rat brain

There is limited knowledge about the distribution of the different G-protein-coupled receptor kinases (GRKs) in the rat brain, especially for the recently cloned isoforms GRK5 and GRK6. In this work an overview will be given of the mRNA expression patterns of four G-protein-coupled receptor kinases, GRK2 (betaARK1), GRK3 (betaARK2), GRK5 and GRK6 in the rat brain. As now shown by us and recently by others GRK2 and GRK3 are widely distributed in rat brain with nearly the same expression pattern. But GRK3, in general, appeared to be weaker expressed than GRK2 in most brain areas. Exceptions were the islands of Calleja, the compact part of the substantia nigra and the locus coeruleus. GRK3 mRNA was very low expressed or absent in the striatum and in some hypothalamic and thalamic nuclei. The expression pattern of GRK6 was also similar to GRK2. In the caudate putamen GRK6 yielded the strongest hybridization signal of all GRK types. GRK5 took a special position. The message for this form was not expressed ubiquitously in the brain but was mainly localized in limbic brain regions with a very prominent expression in the lateral septal area. GRK5 may therefore be involved in reward and addiction. Accordingly, a higher expression level of GRK5 mRNA was found in the lateral septum of cocaine-sensitized rats as compared to controls.