Fluoxetine for migraine prophylaxis: a double-blind trial

Selective serotonin reuptake inhibitors have recently been used in the treatment of migraine. OBJECTIVE: We studied the safety and efficacy of fluoxetine in the prevention of migraine. PATIENTS: Between February 1997 and December 1997, we examined 52 patients (33 women) at the Headache Diagnosis and Therapy Service of the Second University of Naples. Ages ranged from 18 to 65 years, and all patients suffered from migraine without aura according to IHS 1988 criteria. The sample was divided into two groups: group A included 32 patients (19 women; mean age, 36.8 years [SD 12.4]) who received fluoxetine at a dosage of 20 mg per day; group B included 20 patients (14 women; mean age, 38.8 years [SD 15.6]) who received placebo. METHODS: Our study was a single-center, randomized, double-blind, parallel study of fluoxetine for the prophylactic control of migraine and consisted of two phases: 30 days of pharmacological wash out and 6 months of therapy with monthly follow-up. Patients were randomly assigned to two groups: A, fluoxetine or B, placebo. At the first visit, patients provided a detailed history and underwent neurological evaluation and a Zung test for depression. No pathological values were revealed. In order to monitor symptomatology, all patients received a form for the calculation of the total pain index at monthly follow-up. RESULTS: A comparison of the total pain index between basal values (calculated during the period of wash out) and monthly follow-up (calculated monthly during the period of 6 months of the therapy) showed significant reduction (P < .05) beginning from the third month of treatment in the fluoxetine group and no significant reduction in the placebo group. CONCLUSION: Even if preliminary and to be confirmed, these data seem to support the use of fluoxetine in the treatment of migraine.     

Dihydroergokryptine versus dihydroergotamine in migraine prophylaxis: a double-blind clinical trial

Dihydroergokryptine has been evaluated in the prophylaxis of headache attacks in patients with migraine without aura. The study was controlled vs dihydroergotamine with a double-blind crossover design. After a 1-month run-in period, 30 patients were randomized into two groups and submitted to 4 months treatment with dihydroergokryptine 10 mg b.i.d. or dihydroergotamine (controlled release) 5 mg b.i.d. The treatment was repeated in crossover after 2 months washout. The clinical patients' evaluation was determined by monthly Pain Total Index recording, headache daysmonth and analgesic consumption. The patients were considered responsible when Pain Total Index decreased by 50% or more in 1 or more months of each treatment period; otherwise the patients were considered unresponsive. The response rate to dihydroergokryptine was 66% while 48% of cases were responsive to dihydroergotamine. The response rate to both treatments was 41%, while 26 % did not respond to either treatment. Seven cases unresponsive to dihydroergotamine responded positively to dihydroergokryptine while two cases only, resistant to dihydroergokryptine, responded positively to dihydroergotamine. Three cases dropped out during treatment with dihydroergotamine due to gastric pain and nausea, while they did not show any side effects during dihydroergokryptine therapy. During treatment with dihydroergokryptine there was one case of skin rash which disappeared after drug withdrawal. In conclusion, dihydroergokryptine appears to be an effective drug for the prophylaxis of migraine attacks.     

Efficacy of gabapentin in migraine prophylaxis

OBJECTIVE: To compare gabapentin with placebo for use as a prophylactic agent in patients with migraine (with or without aura). STUDY DESIGN AND TREATMENT: After screening, a 4-week, single-blind, placebo baseline period was followed by a 12-week, double-blind, treatment period. The 12-week treatment period consisted of a 4-week titration phase and an 8-week stable-dosing phase. During the 4-week titration phase, patients were started on one 300-mg capsule of gabapentin or matching placebo. Patients were titrated weekly from 900 mg/day (end of week 1) to 2400 mg/day (end of week 4) and had to be receiving a stable dose of study medication by the end of the titration period. Study medication was to be given on a three-times-a-day dosing regimen. METHODS: The study hypothesis was defined a priori as a lower 4-week migraine rate during the second stabilization period for the gabapentin-treated patients as compared with the placebo-treated patients. The analyses were performed with the 4-week migraine rate at baseline as a covariate and center as a blocking factor. RESULTS: At seven participating centers, 143 patients with migraine were randomized in a 2:1 ratio and received either gabapentin (n = 98) or matching placebo (n = 45). Thirty-three patients (24.1%) discontinued prematurely from the study, including 24 (24.5%) of 98 gabapentin-treated patients and 9 (20.0%) of 45 placebo-treated patients; the majority of patients discontinued due to adverse events (16 [16.3%] of 98 gabapentin-treated patients; 4 [8.9%] of 45 placebo-treated patients). Patients included in the analysis were evenly balanced for age, sex, race, weight, and height. The majority of these patients were white (80 [92.0%] of 87) and women (72 [82.8%] of 87), with a mean age of approximately 39.4 years and a history of migraine episodes for a mean of about 21 years. At the end of the 12-week treatment phase, the median 4-week migraine rate was 2.7 for the gabapentin-treated patients maintained on a stable dose of 2400 mg/day and 3.5 for the placebo-treated patients (P =.006), compared with 4.2 and 4.1, respectively, during the baseline period. Additionally, 26 (46.4%) of 56 patients receiving a stable dose of 2400 mg/day gabapentin and 5 (16.1%) of 31 patients receiving placebo showed at least a 50% reduction in the 4-week migraine rate (P =.008). The average number of days per 4 weeks with migraine was also statistically significant and favored gabapentin (P =.006) during stabilization period 2. The median change in 4-week headache rate was statistically significant as well (P =.013). The most frequently reported adverse events for both treatment groups were asthenia, dizziness, somnolence, and infection. Adverse events determined by the investigator to be associated with study drug resulted in patient withdrawal in 13 (13.3%) of 98 gabapentin-treated patients and 3 (6.7%) of 45 placebo-treated patients. Somnolence and dizziness accounted for many of the premature withdrawals among those taking gabapentin. CONCLUSION: Gabapentin is an effective prophylactic agent for patients with migraine. In addition, gabapentin appears generally well tolerated with mild to moderate somnolence and dizziness.     

Amlodipine for migraine prophylaxis

Migraine is among the most common neurologic disorders encountered in clinical practice. In the general US population, the annual incidence has been calculated to be approximately 250 per 100,000 with a point prevalence of 10%. Females are affected more than males. A variety of prophylactic and abortive medications are being used for treatment and several are being studied in clinical trials. Calcium-channel blockers are frequently used prophylactic medications. We report two patients with migraine successfully treated with amlodipine (Norvasc, Pfizer, Inc), a slow calcium-channel blocker. To our knowledge, these are the first reported cases of amlodipine used in migraine prophylaxis.     

Telmisartan in migraine prophylaxis: a randomized, placebo-controlled trial

We evaluated telmisartan 80 mg for migraine prophylaxis. Migraine patients ( n  = 95) with three to seven migraine attacks in 3 months were randomized, double-blind to telmisartan or placebo. The primary end-point was the reduction in the number of migraine days (i.e. a day with ≥ 1 h of symptoms) between the 4-week baseline period and the last 4 weeks of the 12-week treatment period. A responder was recorded when there was a symptom reduction of ≥ 50% in these 4-week baseline and treatment periods. The reduction in migraine days was 1.65 with telmisartan and 1.14 with placebo ( P  > 0.05). Post hoc analyses adjusting for baseline and centre showed a 38% reduction in migraine days with telmisartan vs. 15% with placebo ( P  = 0.03), and a borderline significant difference in responders (40% vs. 25%, P  = 0.07). The incidence of adverse events was similar between treatments. This study indicates that telmisartan might be effective in migraine prophylaxis.     

A randomized double-blind placebo-controlled trial of thioctic acid in migraine prophylaxis

BACKGROUND: Impaired mitochondrial phosphorylation potential may play a role in migraine pathogenesis. Metabolic enhancers, such as riboflavin or coenzyme Q, are effective in migraine prophylaxis and quasi-devoid of adverse effects. Thioctic acid (-lipoic acid) is another substance known to enhance energy metabolism in mitochondria and to be beneficial in diabetic neuropathy. OBJECTIVE: After an open pilot study suggesting its therapeutic antimigraine potentials, we embarked therefore in a randomized controlled trial of thioctic acid (Thioctacid) in migraine prophylaxis steered by the Belgian Headache Society. METHODS: Five Belgian centers recruited 54 migraineurs (43 migraine without aura, 11 with aura; mean age 38 +/- 8 years; 7 males). After a 1-month single-blinded run-in period, 44 patients received either placebo (n = 18) or thioctic acid 600 mg p.o./day (n = 26) for 3 months. RESULTS: Statistical analysis was carried out on an intention-to-treat basis. Monthly attack frequency tended to be reduced between run-in and the 3rd month of treatment in the thioctic acid group compared to placebo (P= .06). The proportion of 50% responders was not significantly different between thioctic acid (30.8%) and placebo (27.8%). Within-group analyses showed a significant reduction of attack frequency (P= .005), headache days (P= .009), and headache severity (P= .03) in patients treated with thioctic acid for 3 months, while these outcome measures remained unchanged in the placebo group. No adverse effects were reported. For logistical reasons this trial was interrupted before the planned 80 patients were enrolled. CONCLUSION: Albeit underpowered, this study tends to indicate that thioctic acid may be beneficial in migraine prophylaxis. Before any firm conclusion can be drawn, however, a large multicenter trial is necessary.     

Efficacy of nimodipine in the prophylaxis of migraine

The efficacy of nimodipine in the prophylaxis of migraine was assessed in a double-blind, placebo-controlled, cross-over study carried out on 33 patients, 20 of whom suffered from classic and 13 from common migraine. Four patients dropped out, but not as a result of the side effects of the drug. The duration of drug treatment was 8 weeks. The dosage used was 30 mg four times daily. Nimodipine proved to be better than placebo, the number of migraine attacks and severity of headache showing a significant reduction. The drug was well tolerated and no marked side effects were noted. The results suggest that nimodipine is a useful new prophylactic drug for migraine, but further studies are needed before its final value can be evaluated.     

Acupuncture in migraine prophylaxis: a randomized sham-controlled trial

The purpose of the present trial was to evaluate semi-standardized acupuncture efficacy in migraine prophylaxis. Twenty-eight subjects with migraine were randomized to the real or sham acupuncture groups. Semi-standardized and standardized minimal acupuncture were used, respectively, in the two groups of patients. They were all treated with 16 acupuncture sessions in 12 weeks. Both groups exhibited similar reductions in: percentage of patients with reduction of migraine>or=40% and >or=50% regarding frequency of migraine attacks, days with migraine, frequency of migraine attacks, average duration of a migraine attack, rate of rescue medication used, average headache severity rate and other parameters compared with the baseline period. Associated symptoms, such as nausea and vomiting, also showed equal estimates in both groups. These findings showed that semi-standardized acupuncture shows no difference from sham acupuncture in preventing migraine attacks.     

Topiramate as an adjunctive treatment in migraine prophylaxis

BACKGROUND: Anticonvulsants now are commonly used for headache prevention. Topiramate, one of the newer anticonvulsants, recently has been demonstrated to be effective as monotherapy for migraine prophylaxis. OBJECTIVE: To assess the efficacy, safety, and tolerability of topiramate as adjunctive prophylactic therapy for migraine. MATERIAL AND METHODS: A prospective trial involving patients with more than 3 migraine attacks per month was performed. Patients continued their usual prophylactic treatment. Baseline analgesic use and frequency and duration of migraine attacks were recorded. A 4-point visual analog scale evaluated severity. Laboratory tests, electrocardiogram, and computed tomography or magnetic resonance imaging were performed before study entry. After informed consent was obtained, patients were instructed to take 25 mg of topiramate per day, with 25- to 50-mg weekly increments to a maximum of 100 mg per day. Safety was assessed at the first month; tolerability and efficacy were assessed every week for the first month and then every month for 3 months. Effectiveness was assessed by comparing baseline and on-treatment migraine status, and data were analyzed by the Fisher exact test. RESULTS: Twenty-five women and 11 men (mean age, 44 years) were evaluated. Existing prophylactic treatment was either propranolol or flunarizine (or both) in 80% of the patients. At 3 months of therapy with topiramate, headache frequency decreased from 17 to 3 episodes per month, headache duration from 559 to 32 minutes, and intensity from 9 to 1 by visual analog scale (P <.001). Improvement in frequency and severity of migraine was observed in 83% of patients. Slight or no changes in headache were observed in 6 patients. Tolerability was good in 30 patients. The most common side effects were acroparesthesias, weight loss, sleepiness, and headache worsening. No adverse interaction with propranolol or flunarizine was observed. CONCLUSIONS: These results suggest that topiramate is efficacious and safe as an adjunctive treatment in patients with migraine whose prior response to prophylactic management has been less than satisfactory.     

Sodium valproate prophylaxis in childhood migraine

Migraine is a cause of recurrent headache in childhood. The efficacy of sodium valproate is well known in the prophylactic treatment of adult migraine, but there are few studies involving the drug's effect in pediatric migraine. OBJECTIVE: To determine the efficacy of sodium valproate in the prophylactic treatment of childhood migraine. METHODS: Fifteen children with migraine according to International Headache Society criteria were included in the study. Headache severity was measured and assessed by Algology unit by a using visual analog scale and a numerical rating scale. All of the subjects were asked to keep a headache diary for 8 weeks. Three subjects who had no headache attacks during the baseline period and two cases who were lost to follow up were excluded. Thus, sodium valproate was initiated in 10 subjects (six boys, four girls), 500 mg/night, and the daily dose was increased up to 1000 mg according to blood levels. Their ages ranged from 9 to 17 (mean age 13.6 +/- 3.2 years). Therapy continued for at least 12 weeks. RESULTS: Headache severity as measured via the mean visual analog score was 6.8 +/- 1.8 at baseline and was 0.7 +/- 1.2 at the end of the treatment period (P = 0.000). Mean headache attacks per month were 6 +/- 4.2 at baseline and were 0.8 +/- 1.9 at the end of the treatment period (P = 0.002). The duration of headache was significantly decreased from a mean of 5.5 +/- 3.9 hours to 1.1 +/- 2.5 hours with treatment (P = 0.001). The observed side effects were dizziness, drowsiness, and increase in appetite; none required drug withdrawal. In two cases, headache attacks recurred after the cessation of valproate, and therapy was restarted. Headache control lasted for six months following cessation of the drug in the remainder of the subjects. CONCLUSION: Sodium valproate appears to be effective and safe in selected patients with childhood migraine.     

A quantification of the placebo response in migraine prophylaxis

To quantify the placebo response of prophylactic therapy in migraine, a meta-analysis of prophylactic, double-blind, placebo controlled migraine studies was performed. The total analysis included 22 studies testing 19 different products, including 2013 patients, of which 828 were treated with placebo. A reduction in migraine attacks of 50% or more (responders) was seen in 23.5%+/-8.0 (95% C.I. 18.3-28.8%) of the patients in the placebo groups and 45.5%+/-15.5 (95% C.I. 37.4-53.6%) in the active groups. A reduction in migraine attacks of 16.8%+/-12.7 (95% C.I. 10.9-22.6%) was observed in the placebo groups and 41.8%+/-11.7 (95% C.I. 36.9-46.6%) in the active groups. We propose that if the percentage of responders in an open-label prophylactic trial in migraine is above 35-40%, or if a reduction in migraine attack frequency is found of 40% or more, further studies are indicated to determine the prophylactic activity of the drug. In all studies included in this analysis, no placebo response was seen above these limits.     

Topiramate for migraine prophylaxis among Chinese population

We evaluated the efficacy and safety of topiramate for migraine prophylaxis among Chinese patients in a multicenter prospective observational study. We found that topiramate at low doses was effective in preventing migraine headache in Chinese patients and was generally well tolerated. There was no difference in baseline headache frequency or intensity between responders and nonresponders.     

Low-dose aspirin for migraine prophylaxis in women

Although migraine is more common among women than men, the only two large, randomized trials of low-dose aspirin for migraine prophylaxis have been conducted in men. As part of the Women's Health Study, an ongoing randomized trial of low-dose aspirin and vitamin E among 39 876 female health professionals aged 45 and older, 1001 women with frequent migraine attacks were assigned to 100 mg of aspirin every other day (n = 525) or aspirin placebo (n = 476). Migraine frequency, as well as severity, duration, and degree of incapacitation, were assessed by self-report on questionnaires 12 months and 36 months after randomization, and also by monthly diaries kept before and after randomization. Women assigned to aspirin reported small and consistent decreases in migraine frequency (59.6% vs. 56.4% assigned to placebo reporting improvement at 36 months; odds ratio 1.13, 95% confidence interval, 0.86--1.48), as well as decreases in severity, duration, and migraine-related incapacitation. These reductions were not, however, statistically significant. These data are compatible with a small treatment effect of low-dose aspirin in the prophylaxis of migraine among middle-aged women.     

Classic migraine: Effective prophylaxis with metoprolol

Metoprolol slow-release tablets (Durules®), 200 mg, given once daily in the morning were compared with placebo in the prophylaxis of classic migraine. The trial comprised eight Scandinavian neurologic centres and was designed as a double-blind cross-over study with 4 weeks' run-in, four weeks washout, and 8 weeks of either treatment. Seventy-seven patients with two to eight migraine attacks per month were entered in the trial, and 73 completed it. A total of 1119 attacks with aura symptoms and 374 without were recorded. Metoprolol was significantly better than placebo with regard to the total frequency of attacks (1.8 versus 2.5 attacks/4 weeks), mean duration of attacks (6.0 versus 8.0 h/attack), mean global rating, and consumption of analgesics per attack: Similar differences could be shown for attacks with aura symptoms alone, except for the duration of attacks. Metoprolol is the first drug for which a prophylactic effect in classic migraine has been convincingly demonstrated.     

A migraine prophylaxis educational intervention in a Medicaid population

OBJECTIVES: To assess migraine prophylactic drug utilization in the Idaho Medicaid population and to evaluate responsiveness of practitioners to an educational intervention from the Idaho Medicaid Drug Utilization Review (DUR) Program. BACKGROUND: While established guidelines recommend migraine prophylactic therapies for defined patient populations and several drugs have demonstrated efficacy, their actual utilization is reportedly low. METHODS: Profiles for Idaho Medicaid patients were reviewed retrospectively to identify candidates for migraine prophylactic therapy based on excessive triptan utilization. Use of a prophylactic agent was then characterized for these patients, and an educational mailing was sent to practitioners directly involved in the care of patients who did not appear to be using prophylaxis. Patient profiles were again assessed 6 months following the mailing to determine if a trial of a prophylactic drug had been attempted. RESULTS: A total of 1909 patients were identified as having at least one claim for a triptan drug in the year studied. Of these patients, 360 appeared to be candidates for prophylaxis, but 154 had no record of prophylactic drug use. In the 6 months following the intervention mailing, 27 of the 91 non-prophylaxis patients (30%) who were still active clients of Idaho Medicaid and who had seen their physician during that time, appeared to have been given a trial of a migraine prophylactic drug. CONCLUSIONS: Following an educational intervention for Idaho Medicaid patients identified through retrospective DUR, a trial of a migraine prophylactic drug was initiated for approximately one-third of potential candidates.     

Selective serotonin reuptake inhibitors for migraine prophylaxis

The objective of this study was to assess the efficacy of sertraline in migraine prophylaxis. Other selective serotonin reuptake inhibitors have been studied for migraine prophylaxis, but this is the first report with sertraline. Twenty-seven subjects were enrolled and baseline assessment of migraine frequency and severity were measured over a 4-week period. Subjects were then randomized to receive placebo or sertraline in a double-blind fashion with headache frequency and severity measured over an 8-week period. Subjects completed a daily diary reporting the occurrence, severity, and degree of impairment associated with migraine.
The headache index, a composite measure of migraine frequency and severity, scores did not significantly improve between assessments at baseline (20.8 ± 14.88), 8 weeks (17.6 ± 12.27), and 12 weeks (16.7 ± 6.38) in the treatment group (n=6) ( P =0.956). This finding is compared to other studies with the serotonin selective reuptake inhibitors, fluoxetine, fluvoxamine, and paroxetine. The authors believe that the selective serotonin reuptake inhibitors are not as effective as conventional migraine prophylaxis medications such as β-blockers, tricyclic antidepressants, or divalproex sodium, but that in patients with comorbid depression who have failed conventional therapy selective serotonin reuptake inhibitors may be effective.     

The dose of propranolol for migraine prophylaxis. Efficacy of low doses

Although propranolol is still the drug of first choice for migraine prophylaxis, the optimal antimigraine dose of this drug is still unknown. The main aim of our study is to clarify this point. Fifty-three patients suffering from severe migraine attacks were given propranolol at low doses, close to or up to 1 mgkg body weight daily, for one month. If the patient responded, then treatment was maintained unchanged for a further two months. If the patient did not respond, propranolol was progressively increased until control was obtained. Thirty-nine (73.5%) patients responded to low doses, and 7 of the 17 patients whose dose had been increased, because of poor or absent response, showed improvement. Five patients did not finish the study because of intolerable side effects, which intensified as the dose was increased. Tolerance was not noticed. In addition to confirming the well-known utility of propranolol in migraine prophylaxis, our results show that low doses are effective in controlling serious migraine bouts in many patients. Fewer than a third of patients will need higher doses in controlling migraine attacks.     

Topiramate prophylaxis and response to triptan treatment for acute migraine

OBJECTIVE: To evaluate the effect of topiramate migraine prophylaxis on subject responsiveness to triptans used for acute symptomatic migraine treatment. BACKGROUND: Clinical experience suggests that prophylactic migraine treatment may enhance the efficacy of symptomatic medications used to treat acute migraine attacks. METHODS: This open-label, single-arm multicenter study consisted of a 6-week baseline period followed by a 16-week topiramate treatment period. Subjects meeting International Headache Society (IHS) criteria for migraine with and without aura signed consent and entered the baseline period. Those with 3 to 12 migraine periods per month during baseline received topiramate prophylactic treatment. Only patients who completed at least 12 weeks of topiramate treatment were included in the data analysis. RESULTS: Of 55 patients screened, 40 subjects entered the topiramate treatment period and 21 subjects received at least 12 weeks of treatment. Mean final dose of topiramate was 124 mg per day (range 50 to 200 mg per day). During the baseline period, the mean percentage of attacks rendered pain-free at 2 hours for the 21 subjects was 46.9% (SD = 31.9), while during the topiramate treatment period it was 44.6% (SD = 32.2) (P= .8). On topiramate, after the first 8 weeks of dosage titration, patients experienced a mean of 3.68 migraine attacks/month, compared to 4.31 during the baseline period (P < .03). Thirteen subjects discontinued because of adverse events. The most commonly reported adverse events were paresthesia, fatigue, anxiety, and dizziness. CONCLUSION: Although topiramate prophylaxis did reduce migraine attack frequency, in this pilot study topiramate prophylactic migraine treatment did not increase the proportion of patients pain-free 2 hours after symptomatic triptan therapy.     

Flunarizine in migraine prophylaxis: predictive factors for a positive response

The efficacy o flunarizine in migraine prophylaxis is confirmed in both open and controlled trials. However, it is unknown what factors may influence a good response to prophylaxis with flunarizine. The aim of this study was to determine the possible predictive factors for therapeutic responsiveness to 3 months' treatment with flunarizine. One-hundred headache patients treated with flunarizine were evaluated. We considered "responders" those patients who recorded a reduction in migraine frequency of 75% after treatment. Statistical analysis revealed four factors which might influence therapeutic responsiveness in our patients. Positive factors were a family history ( p <0.0l) and high intensity of pain ( p <0.0l); negative factors were frequent attacks ( p <0.0l) and a history of analgesic abuse ( p <0.001). Patients with no previous history of analgesic abuse, low frequency of attacks at baseline, higher levels of migraine pain, and positive family history constitute the prototype of flunarizine long-term treatment responders.     

Divalproex extended-release in adolescent migraine prophylaxis: results of a randomized, double-blind, placebo-controlled study

Objective.— To evaluate the efficacy, tolerability, and safety of 3 different doses of divalproex sodium extended‐release vs placebo in the prophylaxis of migraine headaches in adolescents. Background.— Divalproex sodium has been approved for migraine prophylaxis in adults, and previous uncontrolled data suggest divalproex sodium may be effective in preventing migraine in children and adolescents with acceptable tolerability. Methods.— This was a 12‐week, phase 3, randomized, placebo‐controlled, double‐blind, parallel‐group, multicenter study in approximately 300 adolescents aged 12 to 17 years with migraine headaches. At the end of the baseline phase, subjects still meeting study criteria were randomized in a 1 : 1 : 1 : 1 ratio to receive divalproex sodium extended‐release 250 mg, 500 mg, or 1000 mg once daily, or placebo. The primary efficacy variable was reduction from baseline in 4‐week migraine headache rate for each active treatment group vs placebo. Standard safety assessments were conducted and testosterone and sex hormone‐binding globulin levels were collected for postmenarchal females. Results.— There was no statistically significant treatment difference between any divalproex sodium extended‐release dose group and placebo for the primary efficacy variable, reduction from baseline in 4‐week migraine headache rate. There were no statistically significant differences in adverse events between any active treatment group and placebo. A notable dose‐related decrease in platelets was observed, and individuals in all 4 treatment groups had increases in ammonia levels; treatment differences in other laboratory variables were generally small. Among postmenarchal female subjects who were not taking hormonal contraceptives or other steroids, there was no statistically significant change in testosterone levels, but a statistically significant dose‐related increase in sex hormone‐binding globulin was observed. Conclusions.— In the current study, divalproex sodium extended‐release did not differentiate from placebo in the prophylactic treatment of migraine headaches but was generally well‐tolerated in adolescents aged 12 to 17 years.