Tolfenamic acid and migraine--aspects on prostaglandins and leukotrienes

The Inclusion of Tolfenamic Acid into Cyclodextrins Stimulated by Microenvironmental pH Modification as a Way to Increase the Anti-Migraine Effect

PURPOSE

The poorly soluble nonsteroidal anti-inflammatory drug (NSAID), tolfenamic acid (TA), was studied to maximize its solubility, permeability through biological membranes, and pharmacological activity.

METHODS

A mixture with magnesium stearate (MS) - microenvironment pH-modifier was prepared, as well as systems additionally containing incorporating substances methyl-β-cyclodextrin (M-β-CD) and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD). The identification of TA-MS-CD systems was confirmed using experimental methods: X-ray powder diffraction (XRPD) and Fourier transform infrared spectroscopy (FT-IR) with the theoretical support. Apparent solubility study was performed using the paddle apparatus, while in vitro gastrointestinal tract (GIT) and blood-brain barrier (BBB) permeability were conducted by using PAMPA (Parallel Artificial Membrane Permeability Assay). The in vivo part of the study used the mouse nitroglycerin (NTG)-induced migraine pain model.

RESULTS

From practically insoluble substance, TA in TA-MS-M-β-CD system dissolved up to 80.13% ± 2.77%, and in TA-MS-HP-β-CD up to 92.39% ± 3.25% in 180 minutes. An increase in TA permeability was also obtained in the TA-MS-M-β-CD and TA-MS-HP-β-CD systems through GIT membranes (Papp values 2.057 x 10-5 cm s-1 and 2.091 x 10-5 cm s-1, respectively) and through BBB (Papp values 3.658 x 10-5 cm s-1 and 3.629 x 10-5 cm s-1, respectively). The enlargement of the solubility and permeability impacted analgesia. The dose 25 mg/kg of both TA-MS-HP-β-CD and TA-MS-M-β-CD was almost equally effective and only slightly less effective than the dose 50 mg/kg of pure TA. Both TA-MS-HP-β-CD and TA-MS-M-β-CD used at 50 mg/kg more effectively attenuated tactile allodynia in NTG-treated mice than the same dose of pure TA. None of TA forms influenced heat hyperalgesia.

CONCLUSION

Increasing solubility of TA caused an increase of its analgesic effect in an animal model of migraine pain.

Association Between Migraine and Atopic Diseases in Childhood: A Potential Protective Role of Anti-Allergic Drugs

BACKGROUND

Migraine is a common cause of headache in childhood. Several studies have investigated the association between migraine and atopic diseases, mostly in the adult population.

OBJECTIVE

This study aimed to investigate this association in children.

METHODS

A case-control study was conducted across 3 European tertiary care hospitals between June 2014 and August 2014. Cases (n = 229) were children aged 6-18 years consulting for a migraine episode. Controls in the same age range (n = 406) were consulting for a minor injury and did not have a history of recurrent headache. Logistic regression analyses tested the effect of atopic diseases and anti-allergic therapies on occurrence of migraine.

RESULTS

Children with migraine were more likely to have persistent asthma compared to absence of asthma (odds ratio [OR]: 4.57, 95% confidence interval [CI]: 2.04-10.24) and less likely to have been treated by inhaled or nasal corticosteroid (OR: 0.34, 95% CI: 0.15-0.76) or antihistamine therapy (OR: 0.33, 95% CI: 0.18-0.60). The median number of monthly migraine episodes was higher in children with persistent asthma (3; interquartile [IQR]: 1-4; range: 0.5-10) compared to children with intermittent asthma (2; IQR: 1-3; range: 0.1-4) or non-asthmatic children (2; IQR: 1-3; range: 0.1-12) (P < .01).

CONCLUSION

Persistent childhood asthma was associated with increased risk of migraine and higher frequency of migraine attacks. History of anti-asthmatic or anti-allergic therapies was associated with decreased risk of migraine in children and adolescents. The role of these therapies on the pathogenesis and occurrence of migraine needs to be further elucidated because of the huge potential impact in terms of public health.

Urinary leukotriene E4 and prostaglandin F2a concentrations in children with migraine: a randomized study

OBJECTIVES

Pro-inflammatory mediators are thought to play both peripheral and central roles in migraine pathophysiology. Prostaglandins and leukotrienes, known as the eicosanoids, are degradation products of arachidonic acid and constitute signalization components of inflammatory pathways. This study was designed to assess concentrations of leukotriene E4 (LT-E4) and prostaglandin F2a (PG-F2a) in children with migraine.

MATERIALS AND METHODS

This study involved patients aged ≤18 years who presented to the Ondokuz Mayis University Children's Hospital with migrainous headache between January and October 2011. Urinary LT-E4 and PG-F2a concentrations were measured in patients during a headache episode and at a headache-free time and in a control group.

RESULTS

The patient group consisted of 38 girls and 26 boys aged 5-18 years diagnosed with migraine and having at least 6 months of headache, whereas the control group consisted of 21 girls and 29 boys. Mean ± standard deviation (SD) urinary LT-E4 concentrations were significantly higher in patients during a migraine episode than in controls (1466.8±1052.5 pg/ml vs 811.6±460.0 pg/ml, P<0.001). In patients with migraine, both urinary LT-E4 (P<0.001) and PG-F2a (P=0.021) levels were significantly higher during headache than during non-headache periods.

CONCLUSION

Urinary LT-E4 and PG-F2a were both significantly higher in children with migraine during headache than during non-headache periods. The elevation in the levels of these inflammatory mediators was compatible with the hypothesis relating neuroinflammation in trigeminal vascular blood vessels with migraine pathophysiology. Leukotriene antagonists may be effective in the prophylaxis of migraine attacks.

Rofecoxib in migraine

Migraine is a highly prevalent primary headache. The disability of migraine attacks results in considerable economic and social losses. The acute treatment of migraine aims to rapidly and consistently alleviate the head pain and associated symptoms, therefore reducing the headache-related disability, ideally without side effects and recurrence of the attack within 24 h. Although several drug options and different formulations are available, the choice of a specific medication should depend on an individual patients characteristics. Among the available drugs, nonsteroidal anti-inflammatory drugs still represent effective options and a new class of nonsteroidal anti-inflammatory drugs known as selective cyclooxygenase-2 inhibitors may represent an even better-tolerated therapy with regard to gastrointestinal side effects. This article aims to discuss the role of rofecoxib in the acute treatment of migraine. Although this drug was recently withdrawn from the market, it provides a good model to understand the role of the cyclooxygenase-2 inhibitors in migraine therapy overall. The pharmacologic profile and therapeutic use in the acute treatment of migraine of rofecoxib is reviewed. In addition, the limitations of a monotherapeutic orally administered approach and possible ways of raising the efficacy of rofecoxib and other acute migraine treatments are reviewed.

Montelukast for migraine prophylaxis: a randomized, double-blind, placebo-controlled study

OBJECTIVE

To evaluate the efficacy and tolerability of montelukast 20 mg in the prophylactic treatment of migraine.

BACKGROUND

A previous small open-label study in migraine patients suggested prophylactic efficacy for montelukast, an antagonist of the cysteinyl leukotriene receptor that is used in the treatment of asthma. We sought to confirm these findings in a randomized controlled trial.

METHODS

This multicenter, randomized, double-blind, placebo-controlled, parallel-groups study enrolled adult migraine outpatients who experienced > or =3 and < or =8 migraine attacks per month for the last 6 months. Patients were entered into a 2-month, single-blind, placebo run-in phase. Only patients who experienced > or =3 migraine attacks in the second month were eligible to enter the subsequent 3-month, double-blind treatment phase of the study. The primary efficacy endpoint was the percentage of patients reporting at least a 50% decrease in migraine attack frequency per month during the double-blind treatment period (months 3-5) compared to baseline (run-in month 2).

RESULTS

A total of 93 patients were randomized to montelukast 20 mg and 84 patients to placebo at the end of the placebo run-in month 2; 76 patients on montelukast and 72 patients on placebo completed the double-blind treatment period. Over 3 months of treatment, there was no significant difference between the two groups in the percentage of patients who reported at least a 50% decrease in migraine attack frequency per month: 15.4% for montelukast versus 10.3% for placebo (P= .304). In addition, montelukast 20 mg was not significantly superior to placebo on any of the secondary endpoints. There were no differences between treatment groups for adverse events.

CONCLUSION

Montelukast 20 mg was well tolerated in migraine patients but was not an effective prophylactic for prevention of migraine.

The use of the leukotriene receptor antagonist montelukast (Singulair) in the management of dysmenorrhea in adolescents

PURPOSE

Previous studies have shown an increase in leukotrienes in the uterine tissue as well as in the menstrual flow of adult women with dysmenorrhea. An increase in leukotriene-E4, the major urinary leukotriene, was also reported in adolescent girls with dysmenorrhea, further suggesting a possible involvement of these potent vasoconstrictors and inflammatory mediators in generating dysmenorrhea symptoms. In the present study we examined whether blocking leukotrienes might alleviate symptoms of dysmenorrhea in adolescents.

METHODS

Twenty-five adolescents (age 16 +/- 1 years, 4 +/- 1 years post menarche, body mass index 23 +/- 1) with dysmenorrhea participated in a randomized, double blind, crossover study. Thirteen girls received one tablet of montelukast (Singulair, Merck, West Point, PA) 10 mg daily starting on day 21 of the cycle until the last day of the menstrual period for two menstrual cycles, followed by one tablet of placebo (Merck, West Point, PA) daily starting on day 21 of the cycle until the last day of the menstrual period for two additional menstrual cycles. The other 12 girls had a reverse schedule starting with placebo. Participants were instructed to use one or two 200-mg tablets of ibuprofen every 6 h in the event of continuing menstrual symptoms. The Cox Menstrual Symptom Scale was used to assess response to treatment. An intent-to-treat approach was used for data analysis.

RESULTS

Twenty-two girls completed the study. Two girls were noncompliant with the study protocol, and one was withdrawn because of Helicobacter pylori infection. Compared with Cox menstrual score (mean +/- SE) before study (46 +/- 6), there was no significant change in menstrual symptoms during treatment with placebo (Cox score 42 +/- 7) or during treatment with montelukast (Cox score 39 +/- 7), and there was no significant difference between montelukast and placebo treatments as well. Likewise, there was no significant difference between the amount of ibuprofen tablets consumed during the menstrual periods before study (4 +/- 1), while on placebo (3 +/- 1), and while on montelukast (4 +/- 1).

CONCLUSIONS

This study does not support the use of montelukast, in the current FDA-approved dose (for asthma) and commencing immediately before the menstrual period, for treatment of dysmenorrhea. It remains to be determined in further studies whether a higher dose or a prolonged daily use of montelukast may alleviate symptoms of dysmenorrhea in adolescents.

Montelukast in the prophylaxis of migraine: a potential role for leukotriene modifiers

OBJECTIVE

Clinical observation of a decrease in migraine frequency in patients with comorbid asthma taking montelukast, a specific D4 leukotriene receptor antagonist, or zafirlukast, another leukotriene receptor antagonist, prompted us to explore a possible role for leukotriene modifiers in the treatment of migraine. (A further prompt was a pharmacist colleague's observation that a number of patients on these agents reported a decreased sensitivity to perfume triggers and improvement in migraine.)

BACKGROUND

Nonsteroidal anti-inflammatory agents have been used widely in the treatment of migraine. Another class of anti-inflammatory agents, known as leukotriene modifiers, have not been studied to date with regard to their possible role in the treatment of migraine. The name "leukotriene is derived both from the parent molecule, which was originally isolated from leukocytes, and from its three double-bond carbon backbone or triene structure. Both prostaglandins and leukotrienes are derived from the metabolism of arachidonic acid, with prostaglandins coming off the cyclooxygenase pathway and leukotrienes derived via the enzyme 5-lipoxygenase. Both prostaglandins and leukotrienes mediate inflammatory responses. The latter have been studied with regard to their role in the pathophysiology of asthma.

METHODS

A prospective, open-label study evaluating the efficacy of montelukast, 10 mg or 20 mg, in the prophylaxis of migraine in 17 patients is presented in this paper. All 17 patients completed the study that consisted of a 2-month baseline run-in period and a 3-month treatment phase.

RESULTS

Montelukast was extremely well tolerated, and no adverse events were reported by any of the patients. Fifty-three percent showed a reduction of greater than 50% (P<.025) in the frequency of severe attacks, with 41% showing a reduction of greater than 60%. Responders, including modest responders, rated the drug as excellent.

CONCLUSIONS

We conclude, given the limitations of an open-label study design and the small sample size, that montelukast shows potential as an effective, well-tolerated prophylactic agent in migraine. Double-blinded, placebo-controlled studies are warranted. In addition, the leukotrienes, as suggested previously in the literature, may play a role in the pathogenesis of migraine.

Pharmacokinetics of tolfenamic acid in pediatric patients after single oral dose

The pharmacokinetics of tolfenamic acid, a non-steroidal anti-inflammatory drug, were determined following administration of a 1 mg/kg single oral dose of tolfenamic acid suspension to 6 feverish children. Their ages were from 2-14 years (mean 7.5 years) and their weights were from 12-50 kg (mean 29.2 kg). Tolfenamic acid produced a significant fall in temperature (about 2 degrees C) compared to the initial value before oral intake of the drug and was well tolerated without adverse effects. Blood samples for determination of tolfenamic acid concentrations in plasma were obtained at timed intervals for up to 8 h post-dose. Plasma concentrations of tolfenamic acid were determined using a reversed phase HPLC method and pertinent pharmacokinetic parameters were estimated by model-independent standard methods and were the following: the mean peak plasma concentration (Cmax +/- SEM) was 1.09 +/- 0.44 micrograms/ml (range, 0.65-1.63 micrograms/ml) and the mean time (tmax +/- SEM) to reach peak plasma concentration was 1.4 +/- 0.4 h (range, 0.5-3.0 h). The mean area under the plasma concentration-time curve (AUC0-->infinity +/- SEM) was 4.61 +/- 0.40 micrograms.h/ml (range, 2.74-5.98 micrograms.h/ml), the mean elimination half-life (t1/2 +/- SEM) was 2.82 +/- 0.21 h (range, 2.19-3.40 h) and the mean apparent total clearance (CL/F +/- SEM) was 3.83 +/- 0.41 ml/min/kg (range, 2.79-6.08 ml/min/kg).