Update: new uses for lithium and anticonvulsants

The adverse event profile of pregabalin: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

Despite the widespread use of antiepileptic drugs (AEDs) across different neurologic and psychiatric disorders, no study has systematically reviewed all available randomized controlled trials (RCTs) of a given AED to fully uncover its tolerability profile. We aimed at identifying treatment emergent adverse events (AEs) associated with pregabalin through a systematic review and meta-analysis of all available RCTs. We also assessed the association between serious AEs and pregabalin, and investigated whether pregabalin AEs display a dose-response relationship.

METHODS

We searched MEDLINE, EMBASE, and Cochrane CENTRAL to February 2010 for RCTs. Additional studies were identified from reference lists of retrieved papers and from online clinical databases. We selected placebo-controlled, double-blind RCTs investigating the therapeutic effects of pregabalin in adults with any condition. Studies had to include at least 20 subjects per arm and have a duration of at least 4 weeks. AEs were assessed for their association with pregabalin after identification/exclusion of synonyms, rare AEs, and nonassessable AEs due to methodologic limitations. We used relative risks (RRs) to assess the association of any [99% confidence intervals (CIs)] or serious AEs (95% CIs) with pregabalin, and risk differences (RDs, 95% CIs) to investigate dose-response relationships of pregabalin AEs.

KEY FINDINGS

Thirty-eight RCTs were included in our study. Of 39 AEs, 20 (51%) were significantly associated with pregabalin (dizziness, vertigo, incoordination, balance disorder, ataxia, diplopia, blurred vision, amblyopia, tremor, somnolence, confusional state, disturbance in attention, thinking abnormal, euphoria, asthenia, fatigue, edema, peripheral edema, dry mouth, constipation). The highest RRs were found for cognition/coordination AEs. There was no significant association between serious AEs and pregabalin. There was a selective dose-response pattern in the onset of pregabalin AEs, with certain AEs appearing at lower doses than others.

SIGNIFICANCE

Individuals starting treatment with pregabalin are at increased risk for several AEs, particularly those affecting cognition/coordination. Pregabalin AEs appear according to a selective dose-response pattern, possibly reflecting the severity of dysfunction of distinct anatomic structures. These findings may aid clinicians in providing better patient management, and support the value of including in meta-analyses of AED tolerability profiles RCTs performed in different conditions.

Mood stabilizers increase prepulse inhibition in DBA/2NCrl mice

RATIONALE

Lithium and several antiepileptic drugs have mood-stabilizing effects in bipolar disorder and schizophrenia. Both disorders are characterized by deficits in prepulse inhibition (PPI) of the acoustic startle response.

OBJECTIVES

Using the DBA/2 model of naturally low PPI, which is reliably increased by antipsychotics, five mood stabilizers in clinical use were tested to determine whether they would also increase PPI in this model. All drugs were administered intraperitoneally (i.p.) 30 min before testing.

RESULTS

Lithium chloride (30 mg/kg), topiramate (100 and 300 mg/kg), carbamazepine (30, 60, and 100 mg/kg), valproic acid (178 and 316 mg/kg), and lamotrigine (3, 10, and 30 mg/kg) increased percent PPI. The antiepileptic drugs carbamazepine, valproic acid, and lamotrigine at high doses also decreased no-stimulus amplitudes and increased startle amplitudes. At high doses of carbamazepine, valproic acid, and lamotrigine, increases in percent PPI were independent of the increases in startle amplitude.

CONCLUSIONS

The demonstrated efficacy of five mood stabilizers in the DBA/2 model of naturally low PPI points to the translational value of this model in predicting therapeutic activity in schizophrenia and bipolar disorder of compounds with diverse mechanisms of action.

An analysis of the high psychotropic off-label use in psychiatric disorders The majority of psychiatric diagnoses have no approved drug

OBJECTIVE

The authors' goals were to determine the extent of unapproved indications in the DSM-IV-TR, to highlight common off-label uses of psychotropic medications and offer insights into the rationale of the widespread off-label prescribing in psychiatry.

METHOD

Indications for approved psychotropic agents, obtained from the Physicians Desk Reference and the Drug Information Handbook, Clinical Handbook of Psychotropic Drugs, 15th edition, and the Drugs@FDA online database were analyzed in the context of the DSM-IV-TR to determine the percent of DSM-IV-TR disorders that are indications for psychotropic agents. A literature search was performed to determine common off-label uses of major classes of psychotropic medications.

RESULTS

88.5% of all DSM-IV-TR categorized disorders lack an approved medication for their treatment. Atypical Antipsychotics had the most extensive off-label use for DSM-IV-TR categorized disorder, whereas Mood Stabilizers showed the greatest off-label use with regards to disorders and symptoms that are not DSM-IV classified. For each class of medications, more off-label uses exist than FDA-approved uses.

CONCLUSIONS

The vast majority of DSM-IV-TR categorized disorders lack approved medications for their treatment. The large unmet need for approved psychiatric indications may explain the widespread off-label use of psychotropic medications in clinical practice.