Differential cognitive and behavioral effects of topiramate and valproate.

OBJECTIVE: Cognitive effects have been reported during topiramate (TPM) treatment, but effects relative to standard antiepileptic drugs are unclear. METHODS: The authors compared TPM and valproate (VPA) added to carbamazepine (CBZ) in adults with partial seizures. A comprehensive neuropsychological test battery including cognitive, mood, and quality of life measures was used in this multicenter, randomized, double-blind study. After a 4-week baseline, study drug was titrated over 8 weeks to target dosages of 400 mg/d TPM, 2,250 mg/d VPA, or placebo and then maintained for an additional 12 weeks. The neuropsychological test battery was administered at baseline and at the end of titration and maintenance periods. RESULTS: Slightly more patients on TPM dropped out. Neuropsychological data at all three test periods were available for 62 patients. At the end of maintenance, effects of TPM and VPA were comparable, except for two variables (Symbol Digit Modalities Test and Controlled Oral Word Association Test), in which TPM had greater negative effects relative to VPA. The statistical differences appeared to be due in large part to a small subset of patients who were more negatively affected by TPM. Cognitive effects of TPM relative to VPA were greater at the end of titration than at the end of maintenance. CONCLUSIONS: With adjunctive therapy at moderate dose escalation rate, the cognitive effects of TPM are slightly worse overall than VPA in patients who tolerate therapy over several months.

Topiramate titration and tolerability.

OBJECTIVE: To evaluate the tolerability and efficacy of two titration rates for topiramate initiated as adjunctive therapy in adults with partial-onset seizures, with or without secondary generalization, in a multicenter, double-blindtrial. METHODS: After a two-week baseline phase, 188 patients were randomized to either a 50/50 titration schedule (initial dosage 50 mg/d increased in 50-mg/d increments at weekly intervals; n = 95) or to a 100/200 titration schedule (initial dosage 100 mg/d increased by 100-200 mg/d at weekly intervals; n = 93). The maximum dosage of 400 mg/d was therefore achieved in eight weeks or three weeks, respectively. RESULTS: Compared with the 100/200 titration rate, the 50/50 titration rate significantly reduced the cumulative incidence of treatment-emergent adverse events (TEAEs) leading to changes in topiramate therapy (ie., dosage reductions, interruptions or discontinuations of therapy) (p = 0.048) and significantly reduced treatment interruptions or withdrawals due to TEAEs (p = 0.040). Mild or moderate effects involving the central nervous system were the most frequent adverse events. At the final visit, therapeutic responses were comparable in the 50/50 and 100/200 titration groups: median percent seizure reduction was 42% vs. 33%, proportion of patients with 250% seizure reduction was 42% vs. 38%, and proportion of patients with no seizures during double-blind treatment was 14% vs. 10%, respectively. Seizure frequency was substantially reduced from baseline during topiramate titration. At day 22, with the 50/50 titration group receiving 150 mg/d and the 100/200 titration group receiving 400 mg/d, the mean percent seizure reduction was 51% and 54%, respectively. CONCLUSIONS: Gradual initiation of topiramate therapy can significantly enhance patient tolerability without delaying therapeutic response.

Maintenance of the long-term effectiveness of tramadol in treatment of the pain of diabetic neuropathy.

OBJECTIVE: The objective of this study was to evaluate the efficacy and safety of tramadol in a 6-month open extension following a 6-week double-blind randomized trial. RESEARCH DESIGN AND METHODS: Patients with painful diabetic neuropathy who completed the double-blind study were eligible for enrollment in an open extension of up to 6 months. All patients received tramadol 50-400 mg/day. Self-administered pain intensity scores (scale 0-4; none to extreme pain) and pain relief scores (scale -1-4; worse to complete relief) were recorded the first day of the open extension (last day of the double-blind phase) and at 30, 90, and 180 days. RESULTS: A total of 117 patients (56 former tramadol and 61 former placebo) entered the study. On the first day of the study, patients formerly treated with placebo had a significantly higher mean pain intensity score (2. 2+/-1.02 vs. 1.4+/-0.93, P<0.001) and a lower pain relief score (0. 9+/-1.43 vs. 2.2+/-1.27, P<0.001) than former tramadol patients. By Day 90, both groups had mean pain intensity scores of 1.4, which were maintained throughout the study. Mean pain relief scores (2. 4+/-1.09 vs. 2.2+/-1.14) were similar after 30 days in the former placebo and former tramadol groups, respectively and were maintained for the duration of the study. Four patients discontinued therapy due to ineffective pain relief; 13 patients discontinued due to adverse events. The most common adverse events were constipation, nausea, and headache. CONCLUSIONS: Tramadol provides long-term relief of the pain of diabetic neuropathy.

Efficacy of tramadol in treatment of chronic low back pain.

OBJECTIVE: To evaluate the efficacy and safety of tramadol in the treatment of chronic low back pain. METHODS: A 3 phase trial: (1) a washout/screening phase; (2) a 3 week, open label, run-in phase; and (3) a 4 week, randomized, placebo controlled, double blind treatment phase. Three hundred eighty outpatients between 21 and 79 years with chronic low back pain with no or a distant history of back surgery enrolled in the open label phase and were treated with tramadol up to 400 mg/day. At the end of the open label phase, patients who tolerated tramadol and perceived benefit from it were randomized to continue treatment with tramadol or to convert to placebo in the double blind phase. Reasons for discontinuing from the open label phase included adverse events, 78 patients (20.5%); drug ineffective, 23 patients (6.1%); and other reasons, 25 patients (6.6%). Two hundred fifty-four patients entered the double blind phase, during which the daily dose was maintained within the range 200-400 mg tramadol or equivalent amount of placebo. The primary outcome measure in the double blind phase was the time to discontinuation due to inadequate pain relief. RESULTS: The distribution of time to therapeutic failure was significantly (p < or = 0.0001) different in the tramadol group compared to placebo. Kaplan-Meier estimate of the cumulative discontinuation rate due to therapeutic failure was 20.7% in the tramadol group and 51.3% in the placebo group. There were significantly lower (p < or = 0.0001) mean pain visual analog scores (10 cm scale) among tramadol patients (3.5 cm) compared to placebo patients (5.1 cm) at the final visit of the double blind phase. Tramadol patients scored significantly better on the McGill Pain Questionnaire (p = 0.0007) and the Roland Disability Questionnaire (p = 0.0001). Five of 127 tramadol treated patients and 6/127 placebo treated patients discontinued treatment during the double blind phase due to an adverse event. Commonly reported adverse events with tramadol included nausea, dizziness, somnolence, and headache. CONCLUSION: Among patients who tolerated it well, tramadol was effective for the treatment of chronic low back pain.

Efficacy of tramadol in treatment of pain in fibromyalgia.

An outpatient, randomized, double-blind, placebo-controlled clinical trial was conducted to evaluate the efficacy and safety of tramadol in the treatment of the pain of fibromyalgia syndrome. One hundred patients with fibromyalgia syndrome, (1990 American College of Rheumatology criteria), were enrolled into an open-label phase and treated with tramadol 50-400 mg/day. Patients who tolerated tramadol and perceived benefit were randomized to treatment with tramadol or placebo in the double-blind phase. The primary efficacy outcome measurement was the time (days) to exit from the double-blind phase because of inadequate pain relief, which was reported as the cumulative probability of discontinuing treatment because of inadequate pain relief. One hundred patients entered the open-label phase; 69% tolerated and achieved benefit with tramadol. These patients were then randomized to continue tramadol (n = 35) or convert to a placebo (n = 34) during a 6-week, double-blind treatment period. The Kaplan-Meier estimate of cumulative probability of discontinuing the double blind period because of inadequate pain relief was significantly lower in the tramadol group compared with the placebo group (p = 0.001). Twenty (57.1%) patients in the tramadol group successfully completed the entire double-blind phase compared with nine (27%) in the placebo group (p = .015). These results support the efficacy of tramadol over a period of 6 weeks in a double blind study for the treatment of the pain of fibromyalgia in a group of patients who had been determined to tolerate it and perceive a benefit.

Tramadol allows reduction of naproxen dose among patients with naproxen-responsive osteoarthritis pain: a randomized, double-blind, placebo-controlled study.

OBJECTIVE: To demonstrate that in patients receiving naproxen for the pain of osteoarthritis (OA), the addition of tramadol will allow a reduction in the naproxen dosage without compromising pain relief. METHODS: This trial consisted of a 5-week open-label run-in and an 8-week double-blind phase. Patients with at least moderate pain (> or =40 mm on a 100-mm visual analog scale) of OA of the knee after a 1-week medication washout were treated with naproxen 500 mg/day for 1 week. Patients whose pain scores were reduced to <20 mm were discontinued. The remaining patients received naproxen 1,000 mg/day for 3 weeks. Tramadol 200 mg/day was added during the third week. Patients were then randomized in a double-blind manner to continue tramadol 200 mg/day or to begin placebo in addition to naproxen. Randomization was stratified based on response to naproxen 1,000 mg/day. During the double-blind phase, the naproxen dose was reduced by 250 mg every 2 weeks. The primary efficacy end point was the minimum effective naproxen dose (MEND). The MEND was defined as 250 mg above the naproxen daily dosage at which pain relief was no longer adequate. Patients discontinuing the double-blind phase of the study for reasons other than lack of efficacy were assigned a MEND equal to the last naproxen dose received. If the effect of treatment between the responder and nonresponder groups was statistically different, the difference in the MEND was assessed separately within the groups. RESULTS: Of 236 patients randomized (mean age 61 years; 147 females), 90 were stratified as naproxen responders and 146 as naproxen nonresponders. There was a significant difference (P = 0.040) in the treatment effect between the naproxen responders and nonresponders, thus demonstrating a difference in the way responders and nonresponders react to a decrease in naproxen dosage after the addition of tramadol. Among naproxen responders, the MEND was significantly lower in patients receiving tramadol (n = 36) than in patients receiving placebo (n = 54), 221 mg versus 407 mg, respectively (P = 0.021). For the naproxen nonresponders, the mean MEND was 419 mg in the tramadol group and 396 mg in the placebo group (P = 0.706). CONCLUSION: In patients with painful OA of the knee responding to naproxen 1,000 mg/day, the addition of tramadol 200 mg/day allows a significant reduction in the dosage of naproxen without compromising pain relief.

Slowing the titration rate of tramadol HCl reduces the incidence of discontinuation due to nausea and/or vomiting: a double-blind randomized trial.

BACKGROUND: Ultram [tramadol hydrochloride (HCl)] is a centrally acting analgesic that is widely prescribed for the treatment of moderate to moderately severe chronic pain. Although tramadol is generally well tolerated, some patients discontinue use early in the course of treatment because of nausea and vomiting. OBJECTIVE: To investigate the effect of three initial titration rates of tramadol HCl on the incidence of discontinuation due to nausea and/or vomiting in patients who previously did not tolerate tramadol HCl. METHOD: A multicentre, outpatient, randomized double-blind study was conducted, comprised of two phases: a 14-day open-label run-in phase and a 28-day double-blind phase. In the run-in phase the dose of tramadol was titrated over 4 days to the target of 200 mg/day. Patients who discontinued tramadol HCl due to nausea and/or vomiting in the open-label phase were eligible to enter the 28-day double-blind phase after a 10-day wash-out. Patients were randomized to one of three groups using a 10-, 16- or a 13-day titration schedule in order to achieve a target dosage of either 200 mg/day (10- and 16-day titration groups) or 150 mg/day (13-day titration group). The number of discontinuations due to nausea and/or vomiting in each group were compared. RESULTS: Significantly fewer patients (22%) discontinued because of nausea and/or vomiting in the 13- and 16-day titration groups compared to the 10-day group (P=0.008 and P=0.006, respectively). The time to discontinuation was also significantly delayed in the 13- and 16-day groups compared to the 10-day group (P=0.006 and P=0.007, respectively). The outcome of the 13-day titration to 150 mg/day was essentially the same as that of the 16-day titration to 200 mg/day, suggesting that this is a true rate effect rather than being dose related. CONCLUSION: This study demonstrated that a slower titration rate of tramadol HCl improves tolerability in patients who previously discontinued therapy due to nausea and/or vomiting. This study also demonstrates that the rate of titration of tramadol HCl rather than the target dose is the major determinant of tolerability.

Double-blind randomized trial of tramadol for the treatment of the pain of diabetic neuropathy.

OBJECTIVE: The objective of this study was to evaluate the efficacy and safety of tramadol in treating the pain of diabetic neuropathy. BACKGROUND: The pain of diabetic neuropathy is a major cause of morbidity among these patients and treatment, as with other small-fiber neuropathies, is often unsatisfactory. Tramadol is a centrally acting analgesic for use in treating moderate to moderately severe pain. METHODS: This multicenter, outpatient, randomized, double-blind, placebo-controlled, parallel-group study consisted of a washout/screening phase, during which all analgesics were discontinued, and a 42-day double-blind treatment phase. A total of 131 patients with painful diabetic neuropathy were treated with tramadol (n=65) or placebo (n=66) tramadol, which were administered as identical capsules in divided doses four times daily. The primary efficacy analysis compared the mean pain intensity scores in the tramadol and placebo groups obtained at day 42 of the study or at the time of discontinuation. Secondary efficacy assessments were the pain relief rating scores and a quality of life evaluation based on daily activities and sleep characteristics. RESULTS: Tramadol, at an average dosage of 210 mg/day, was significantly (p < 0.001) more effective than placebo for treating the pain of diabetic neuropathy. Patients in the tramadol group scored significantly better in physical (p=0.02) and social functioning (p=0.04) ratings than patients in the placebo group. No statistically significant treatment effects on sleep were identified. The most frequently occurring adverse events with tramadol were nausea, constipation, headache, and somnolence. CONCLUSIONS: The results of this placebo-controlled trial showed that tramadol was effective and safe in treating the pain of diabetic neuropathy.

Efficacy of felbamate monotherapy in patients undergoing presurgical evaluation of partial seizures.

The efficacy and safety of felbamate monotherapy were evaluated in 52 patients with refractory partial seizures with or without secondary generalization in a double-blind, randomized, placebo-controlled trial. Each patient completed a routine evaluation for epilepsy surgery and was randomized to receive either felbamate, titrated to a maximum daily dose of 3600 mg over 2 days, or placebo during the 10-day, inpatient, treatment phase. An intent-to-treat analysis was performed on the data of all 52 patients who received study medication, while a separate efficacy analysis also was performed on the data of 43 evaluable patients, which excluded protocol violators. The endpoint of the trial was completing 10 days of treatment or the occurrence of a fourth seizure. The primary efficacy variable was the average daily seizure frequency during the treatment phase for each patient. For the intent-to-treat analysis based on all 52 patients who received study medications, the mean rank of the daily seizure frequency for patients treated with felbamate was 21.6 compared to 29.6 for patients treated with placebo (P = 0.065). In the analysis based on the 43 evaluable patients, the mean rank of the daily seizure frequency for felbamate-treated patients was 17.0 compared to 25.4 for placebo-treated patients. This difference was statistically significant (P = 0.032) in favor of felbamate. Seizure frequency was decreased by 89.5% compared to baseline in nine patients who completed 10 days of felbamate therapy. This study permitted the rapid determination of the anticonvulsant activity of felbamate and demonstrated that felbamate is effective as monotherapy for the treatment of partial seizures.

Prototype antiepileptic drug clinical development plan.

Antiepileptic drug (AED) development has been generally difficult owing to many factors: regulatory requirements for demonstration of efficacy and safety, subject availability, traditional trial designs, and physicians' beliefs about epilepsy and its treatment. The U.S. Food and Drug Administration (FDA) regulations require a new drug to be shown safe and effective for its intended use before it can be marketed. The unambiguous proof required is a formidable hurdle for AED development. We report a recent clinical development plan highlighting innovations in clinical trial design that have addressed these requirements, discuss alternative endpoints, and compare the results of various trial designs at various stages of development. This model clinical development plan includes trials relevant to all three clinically relevant contexts in which an AED might be used: as an adjunct to an existing regimen, as a substitution for much of an existing AED regimen, and as monotherapy.

Felbamate: a double-blind controlled trial in patients undergoing presurgical evaluation of partial seizures.

We studied the efficacy and safety of felbamate, an investigational antiepileptic drug, in a unique, double-blind, placebo-controlled trial. Sixty-four patients with refractory partial-onset seizures who completed a routine evaluation for epilepsy surgery met seizure frequency entry criteria. Each patient received felbamate or placebo in addition to the anticonvulsant regimen present at the conclusion of the presurgical evaluation. The treatment phase consisted of an 8-day inpatient period and a 21-day outpatient period. The efficacy variable was time to fourth seizure. The difference in time to fourth seizure was statistically significant (p = 0.028) in favor of felbamate. Eighty-eight percent of the patients in the placebo group had a fourth seizure during the treatment phase compared with 46% of the patients in the felbamate group (p = 0.001). Adverse experiences with felbamate were generally mild or moderate in severity. This trial demonstrated the ability of felbamate to quickly and safely reduce the occurrence of frequent partial-onset seizures and maintain effective seizure control following reductions in the dosages of standard antiepileptic drugs.

Creutzfeldt-Jakob Disease. Possible transmission to humans by consumption of wild animal brains.

Although the natural mode of spread of the agent responsible for Creutzfeldt-Jakob disease is unknown, several reports suggest oral transmission through consumption of contaminated food or brain. This report summarizes four cases of Creutzfeldt-Jakob disease in which a history of eating the brains of wild goat or squirrel was obtained. These cases support the hypothesis of possible acquisition of Creutzfeldt-Jakob disease by ingestion of the agent from a presumptive reservoir in the central nervous system of wild animals.

Conservative management of focal intracerebral infection.

One case of bacterial brain abscess and one case of multiple tuberculomas with tuberculous meningitis were treated non-surgically for an extended time with the aid of serial CT. Complete clinical and radiologic resolution was demonstrated in both cases. The features and the sequence of events in these cases suggest that conservative management of focal intracerebral infection may often obviate the need for surgical intervention.