Anticonvulsant Hypersensitivity Syndrome: Implications for Pharmaceutical Care

Meta-analysis of EEG biofeedback in treating epilepsy

About one third of patients with epilepsy do not benefit from medical treatment. For these patients electroencephalographic (EEG) biofeedback is a viable alternative. EEG biofeedback, or neurofeedback, normalizes or enhances EEG activity by means of operant conditioning. While dozens of scientific reports have been published on neurofeedback for seizure disorder, most have been case series with too few subjects to establish efficacy. The purpose of this paper is to meta-analyze existing research on neurofeedback and epilepsy. We analyzed every EEG biofeedback study indexed in MedLine, PsychInfo, and PsychLit databases between 1970 and 2005 on epilepsy that provided seizure frequency change in response to feedback. Sixty-three studies have been published, 10 of which provided enough outcome information to be included in a meta-analysis. All studies consisted of patients whose seizures were not controlled by medical therapies, which is a very important factor to keep in mind when interpreting the results. Nine of 10 studies reinforced sensorimotor rhythms (SMR) while 1 study trained slow cortical potentials (SCP). All studies reported an overall mean decreased seizure incidence following treatment and 64 out of 87 patients (74%) reported fewer weekly seizures in response to EEG biofeedback. Treatment effect was mean log (post/pre) where pre and post represent number of seizures per week prior to treatment and at final evaluation, respectively. Due to prevalence of small groups, Hedges's g was computed for effect size. As sample heterogeneity was possible (Q test, p=.18), random effects were assumed and the effect of intervention was -0.233, SE = 0.057, z = -4.11, p<.001. Based on this meta-analysis, EEG operant conditioning was found to produce a significant reduction on seizure frequency. This finding is especially noteworthy given the patient group, individuals who had been unable to control their seizures with medical treatment.

Topiramate for Use in Adult Migraine Prophylaxis

Objective:

To review studies comparing topiramate with placebo or other migraine prophylaxis agents in order to outline the role of topiramate in the pharmacologic prevention of adult migraine and to provide clinicians with evidence for rationale of its use.

Data Sources:

Primary studies and review articles were identified via a MEDLINE search (1960–November 2008). Search terms included topiramate, antiepileptic, anticonvulsant, migraine prophylaxis, and migraine prevention. Additional references were obtained from bibliographies of those resources.

Study Selection and Data Extraction:

All relevant information extracted from randomized, controlled studies and systematic reviews evaluating the efficacy, safety, and pharmacology of topiramate in the prevention of adult migraine were included.

Data Synthesis:

Topiramate is approved for the prevention of adult migraine. It has historically been used in the treatment of seizure disorders but received approval for migraine prophylaxis in 2004. The exact mechanism of its antimigraine effect remains unknown, but modulation of sodium channels, γ-aminobutyric acid, and glutamate activity seem to be involved, given the proposed shared pathophysiology between seizure and migraine. Two pivotal trials comparing topiramate with placebo led to approval for migraine prophylaxis in the US and a third similar trial that compared topiramate with propranolol secured licensure in Europe. Additional studies evaluated optimal dosing up to 200 mg daily and duration of therapy through 14 months. These trials demonstrated the ability of topiramate 50 mg twice daily, administered for up to 14 months, to safely reduce migraine frequency, duration, and severity. Limited information from comparative studies suggests a similar effect of topiramate and other agents, including divalproex sodium, propranolol, and timolol. The most common adverse effect observed among all trials was mild-to-moderate paresthesias that were transient in nature. Other adverse effects commonly reported include gastrointestinal upset and cognitive impairment. Adverse effects were more likely to occur during titration periods. Topiramate's safety profile appears to be as good as or better than that of other prophylactic agents.

Conclusions:

Topiramate is an appropriate first-line drug to consider for prevention of adult migraine. The efficacy and safety of topiramate in migraine prophylaxis has been well established in clinical trials and is comparable with other approved agents for this indication. When choosing among these agents, prescribers should consider the adverse effect profile, route of administration, cost, and comorbidities.

ACPE Universal Program Number:

407-000-09-052-H01-P (Pharmacists); 407-000-09-052-H01-T (Technicians)

Physiological and pharmacological roles of ABCG2 (BCRP): recent findings in Abcg2 knockout mice

The multidrug transporter ABCG2 (BCRP/MXR/ABCP) can actively extrude a broad range of endogenous and exogenous substrates across biological membranes. ABCG2 limits oral availability and mediates hepatobiliary and renal excretion of its substrates, and thus influences the pharmacokinetics of many drugs. Recent work, relying mainly on the use of Abcg2(-/-) mice, has revealed important contributions of ABCG2 to the blood-brain, blood-testis and blood-fetal barriers. Together, these functions indicate a primary biological role of ABCG2 in protecting the organism from a range of xenobiotics. In addition, several other physiological functions of ABCG2 have been observed, including extrusion of porphyrins and/or porphyrin conjugates from hematopoietic cells, liver and harderian gland, as well as secretion of vitamin B(2) (riboflavin) and possibly other vitamins (biotin, vitamin K) into breast milk. However, the physiological significance of these processes has been difficult to establish, indicating that there is still a lot to learn about this intriguing protein.

Diarrhea, negative t-waves, fever and skin rash, rare manifestation of carbamazepine hypersensitivity: a case report

Introduction

Antiepileptic drug induced hypersensitivity syndrome is a rare side effect of some of the first line anticonvulsive drugs such as carbamazepine and other aromatic agents. We are the first to mention a rare case of gastrointestinal, skin and cardiac findings related to carbamazepine administration, which is very uncommon and needs to be reported.

Case presentation

We report on a 62-year-old Caucasian woman with carbamazepine associated hypersensitivity syndrome, who developed diarrhea, fever, skin lesions, pericardial effusion and pathology on electrocardiogram with terminal negative T waves in I, II, aVL, V₅ and V₆,. After withdrawal of carbamazepine and administration of methylprednisolone, all initial symptoms improved, white blood cell count normalized, pericardial effusion resolved and pathologic electrocardiogram findings resolved.

Conclusion

Anticonvulsive drug hypersensitivity syndromes can present with a wide spectrum of unspecific symptoms, which the prescribing clinician should be aware of.

Recent Publications on Medications and Pharmacy

Hospital Pharmacy presents this feature to keep pharmacists abreast of new publications in the medical/pharmacy literature. Articles of interest will be abstracted monthly regarding a broad scope of topics. Suggestions or comments may be addressed to: Jacyntha Sterling, Drug Information Specialist at Saint Francis Hospital, 6161 S Yale Ave., Tulsa, OK 74136 or e-mail: jasterling@saintfrancis.com .