Clinical issues in the use of carbamazepine in psychiatry: a review

Lithium but not carbamazepine augments antidepressant efficacy of mirtazapine in unipolar depression: an open-label study

BACKGROUND

The purpose of the present open-label study was to investigate the antidepressant efficacy of lithium and carbamazepine as augmentation strategies in unipolar depressed inpatients.

METHOD

Forty-six patients suffering from unipolar depression (major depressive episode according to DSM-IV criteria) were pre-treated with mirtazapine for 2 weeks initially (week -2 to week 0). Thereafter, the patients received either continuation of mirtazapine monotherapy (n = 23), combination treatment with mirtazapine and lithium (n = 13), or combination therapy with mirtazapine and carbamazepine (n = 10) for further 3 weeks (week 0 to week 3). Severity of depression was estimated weekly using the 21-item version of the Hamilton Depression Rating Scale (21-HAMD). Response was defined by a reduction of at least 50% in the 21-HAMD sum score after 3 weeks of pharmacotherapy (week 0-3).

RESULTS

Additional administration of lithium, but not adjunctive carbamazepine significantly augmented the antidepressant efficacy of mirtazapine in the unipolar depressed patients. Moreover, carbamazepine but not lithium significantly lowered the serum concentrations of mirtazapine.

CONCLUSION

Whereas the clinical importance of anticonvulsants in the treatment of bipolar disorder is not in doubt, the therapeutic efficacy of antiepileptic drugs such as carbamazepine is obviously limited in the pharmacotherapy of unipolar depression.

Comparative cognitive effects of carbamazepine and gabapentin in healthy senior adults

PURPOSE

This study compared the cognitive effects of carbamazepine (CBZ) and gabapentin (GBP) in healthy senior adults by using a randomized, double-blind crossover design.

METHODS

Thirty-four senior adults were randomized to receive one of the two drugs followed by a 5-week treatment period. A 4-week washout phase preceded initiation of the second drug. Antiepileptic drugs (AEDs) were titrated to target doses of either CBZ (800 mg/day) or GBP (2,400 mg/day). Primary outcome measures were standardized neuropsychological tests of attention/vigilance, psychomotor speed, motor speed, verbal and visual memory, and the Profile of Mood State (POMS), yielding a total of 17 variables. Each subject received cognitive testing at predrug baseline, end of first drug phase, end of second drug phase, and 4 weeks after completion of the second drug phase.

RESULTS

Fifteen senior adults (mean age, 66.5 years; range, 59-76 years) completed the study. Seniors completing the study did not differ significantly from noncompleting seniors in terms of demographic features or baseline cognitive performances. Fifteen of the 19 seniors not completing the study dropped out while receiving CBZ. Adverse events were frequently reported for both AEDs, although they were more common for CBZ. Mean serum levels for the completers were within midrange clinical doses (CBZ, 6.8 microg/ml; GBP, 7.1 microg/ml). Significant differences between CBZ and GBP were found for only one of 11 cognitive variables, with better attention/vigilance for GBP, although the effect was modest. Performances on the nondrug average were significantly better on 45% of cognitive variables compared with CBZ and 36% compared with GBP. The overall pattern of means favored GBP over CBZ on 15 of 17 (p < 0.001), nondrug over CBZ on 17 of 17 (p < 0.0000), and nondrug over GBP on eight of 17 (NS).

CONCLUSIONS

Mild cognitive effects were found for both AEDs compared with the nondrug average condition. The magnitude of difference between the two AEDs across the cognitive variables was modest. Self-reported mood was not significantly affected by either AED. However, overall tolerability and side-effect profile of CBZ were poorer than those of GBP in senior adults at doses and titration rates reported in this study.

Stress-dependent antinociceptive effects of carbamazepine: a study in stressed and nonstressed rats

1. The present study examined the antinociceptive effects of carbamazepine on the tail flick test in stressed and nonstressed rats. 2. Carbamazepine produced a bimodal antinociceptive effect in stressed rats, the first peak appearing 30 min and the second 4 h after injection. Antinociceptive effect was not observed in nonstressed rats. 3. The secondary, but not the initial, carbamazepine antinociception in stressed rats was blocked by naloxone (0.2 mg/kg, i.p.), an opioid receptor antagonist. 4. Caffeine (5 mg/kg, i.p.), an adenosine A1/A2 receptor antagonist, inhibited the both initial and secondary antinociceptive effects of carbamazepine in stressed rats. 5. Carbamazepine increased the antinociceptive effect induced by either i.p. or i.c.v. administration of N6-cyclohexyl adenosine (CHA), an adenosine A1 receptor agonist, in stressed rats, but decreased it in nonstressed rats. 6. These results suggest that the initial antinociceptive effect of carbamazepine in stressed rats may be produced via an activation of the adenosine A1 receptors, such as was produced by CHA. The secondary long-lasting antinociceptive effects of carbamazepine may be mediated by an activation of opioid systems. 7. Furthermore, the initial activation of the adenosine A1 receptors by carbamazepine may be a triggering factor for the subsequent long-lasting activation of the opioid system, which results in the antinociception effects.

Is carbamazepine a potential drug of abuse?

A case is reported of a 20-year-old female student who had been abusing carbamazepine with alcohol and described a resulting sense of euphoria. The literature is reviewed for evidence to support this claim, and possible mechanisms to account for the euphorigenic effect of alcohol and carbamazepine are discussed.

A clinical approach to the pharmacotherapy of aggression in children and adolescents

Overt aggression in its various forms is the most prevalent symptom presenting to pediatric mental health providers, regardless of setting. It is a behavior with a heterogeneous etiology and requires a comprehensive approach to evaluation and treatment. Evaluation of the aggressive child must assess medical, neurologic, psychiatric, psychosocial, familial, and/or educational contributions to behavioral dyscontrol. Multimodal treatment is generally required. At present, there is no single medication to recommend for the treatment of aggressive behavior. Multiple medications have clinically been used in a nonspecific fashion to target excessive childhood aggression. Although successful for some, this approach increases risk for ineffective interventions accompanied by side effects. Until a scientific understanding of the developmental neurobiology of aggression leads to more specific treatment, this review suggests the use of a diagnostic-based approach to the pharmacology of aggression (FIG. 1). Descriptive diagnostic techniques should be used to define the presence of any primary or comorbid psychiatric disorder that presents with aggression as an associated symptom. Treating aggression in the context of these psychiatric syndromes appears to be the most direct approach. Aggression occurring in the context of a medication-responsive psychiatric diagnosis appears most sensitive to pharmacologic intervention. Presently, evidence for efficacy is strongest for aggression in the context of ADHD, psychotic disorder, adolescent-onset bipolar disorder, and ictal aggression It remains less clear that medication can help aggression when it occurs independently of a pharmacologically treatable comorbid psychiatric disorder. Aggression may respond to a target symptom approach where discrete behavioral symptoms that contribute to aggression, such as irritability, explosiveness, fear, or impulsivity, may be modified by medication intervention (FIG. 1). When treatment is approached in this fashion, it is standard practice to use the least toxic and safest intervention first. Behavioral treatment based on contingency management principles could be initially recommended. Medication trials should first use medications that have demonstrated empiric efficacy in reducing aggression (TABLE 1) and that have a favorable safety profile. Neuroleptics to treat aggression in nonpsychotic psychiatrically referred youth should be kept to a minimum, secondary to their significant adverse risk profile. Alternative medications, such as selective serotonin reuptake-inhibiting antidepressants, buspirone, lithium, anticonvulsants, opiate blocking agents, propranolol, nadolol, and clonidine, deserve more clinical research in pediatric aggression. These medications may offer effective and less toxic alternatives in the pharmacologic treatment of inappropriate excessive childhood aggression.

Drug strategies and treatment-resistant schizophrenia

OBJECTIVES

The aims of the paper are to review the notion of treatment resistance in schizophrenia and consider the factors important in determining non-responsiveness to standard neuroleptic treatment, and to review the strategies currently available in the treatment of such patients, including an evaluation of recently-introduced, novel drug treatments.

METHOD

A selective review of the literature relating to treatment resistance was undertaken using medline searches, followed by cross-checking for further articles identified in these references.

RESULTS

The various treatment approaches available are considered, including adjunctive treatment with lithium or carbamazepine. The risks and benefits of high dose antipsychotic treatment are discussed. The possible benefits and side-effects of new treatments, particularly the atypical neuroleptics, are also reviewed.

CONCLUSIONS

The reasons why a proportion of patients with schizophrenia fail to respond to standard neuroleptic treatment are ill-understood. Nevertheless, initial assessment should include identification of any factors that may be related to a patient's poor response, such as poor compliance, substance use or epilepsy. This may help to determine an appropriate treatment strategy. There is a need to be systematic and to ensure that patients be given an adequate trial of each treatment tested in terms of duration and dosage. The available evidence does not support the use of high doses of neuroleptics for the majority of patients. Adjunctive treatments, such as lithium, carbamazepine or benzodiazepines may be beneficial in non-responsive patients, particularly if certain target symptoms are present. Atypical neuroleptics, particularly clozapine, have proved particularly effective in non-responsive patients as well as those sensitive to the motor side-effects of standard drugs. However, the high risk of agranulocytosis with clozapine is a problem; also the drug and the necessary haematological monitoring are expensive. There are hints that some of the other, new, atypical neuroleptics have some benefit in non-responsive patients, but controlled studies are required.

Recent advances in geriatric psychopharmacology

Psychopharmacotherapy of the elderly must take into account the effects of age-related changes in the structure and function of the brain and various organs. In general, older people are more sensitive than young people to both the therapeutic and toxic effects of psychotropic medications, necessitating lower doses and longer dosage intervals. This holds true for the treatment of 5 major types of psychiatric illness (depression, bipolar disorder, anxiety, psychotic disorders and dementia). The tricyclic antidepressants, although efficacious, inexpensive, and backed by 30 years of experience, are less well tolerated by the elderly than are newer antidepressants such as the selective serotonin uptake inhibitors. Problems with monoamine oxidase (MAO) inhibitors, including orthostatic hypotension and restrictions in diet and other medication use, have been overcome by the advent of reversible selective inhibitors of MAO-A, but the efficacy of these in the elderly has yet to be proven in clinical trials. Lithium remains the mainstay for the treatment of bipolar disorder. However, careful dosing and monitoring of plasma lithium concentrations are required in the elderly due to changes in pharmacokinetics and pharmacodynamics which make older patients very sensitive to the toxic effects of this medication. Similarly, age-related changes in the pharmacokinetics and pharmacodynamics of the benzodiazepines, the most frequently prescribed medications for anxiety in the elderly, result in recommendations for lower doses and preferential use of those agents metabolised by conjugation (e.g. oxazepam). Buspirone, a partial serotonin 5-HT1A-agonist which is better tolerated than benzodiazepines in the elderly, may be used as an alternative. The elderly are extremely sensitive to extrapyramidal adverse effects which the typical antipsychotics (neuroleptics) exhibit to varying extents. The selection of a suitable agent for the treatment of a psychotic disorder should be based upon the adverse effect profile of the drug and the specific symptoms and situation of the patient. The newer atypical antipsychotics, clozapine and risperidone, have yet to be well-studied in the elderly. Dementia, exemplified by Alzheimer's disease, is almost exclusively an illness of the elderly. Only one medication, tacrine, has been approved for its treatment, based on extensive basic research and positive results of several clinical trials. Its long-term benefits have yet to be determined and it has several adverse effects, including a tendency to increase liver enzymes to the extent that the medication has to be discontinued.(ABSTRACT TRUNCATED AT 400 WORDS)

Therapy and prevention of affective illness by total sleep deprivation

The therapeutic effect of total sleep deprivation (SD) given twice a week, for 4 weeks, was investigated in 16 drug-free patients with major affective disorders. The response was excellent in five patients, satisfactory in three and minimal in eight patients. Six of these patients were treated prophylactically once a week, and four had an excellent response. Additionally, out of five normothymic drug-free patients with affective illness treated prophylactically with SD, without prior therapeutic SD treatment, three had an excellent response. The majority of responders were rapid cycling patients. This method is worth applying to patients resistant to classical treatment.

Pharmacological manipulation of aggressiveness and impulsiveness in healthy volunteers

1. Pharmacological treatments used to control disruptive and aggressive behaviour in patient groups are discussed. 2. Techniques developed to elicit aggression in human volunteers in the laboratory are outlined. 3. Pharmacological manipulations tested on these techniques are described and both their relevance to the clinic and directions for future work are discussed.

Monotherapy with conventional and controlled-release carbamazepine: a double-blind, double-dummy comparison in epileptic patients

1. Twenty-one epileptic patients completed a double-blind, double-dummy, random order, crossover comparison of conventional carbamazepine (CBZ, Tegretol, Ciba-Geigy) with a new controlled-release formulation (CBZ-CR, Tegretol Retard). All participants were stabilised on maximally tolerated doses of CBZ as monotherapy (one twice daily, twelve three times daily, eight four times daily). Each preparation was taken with a matched placebo of the other for 4 weeks. 2. Peak serum CBZ concentrations (mean +/- s.e. mean) were lower (CBZ 11.4 +/- 0.4 mg l-1; CBZ-CR 10.4 +/- 0.5 mg l-1; P less than 0.01) and times to peak longer (CBZ 3.6 +/- 0.5 h, CBZ-CR 5.2 +/- 0.7 h, P less than 0.01) during CBZ-CR treatment. Mean CBZ concentrations, however, were also slightly reduced with the new formulation (CBZ 9.9 +/- 0.3 mg l-1; CBZ-CR 9.1 +/- 0.5 mg l-1, P less than 0.05) and this was associated with greater seizure frequency (CBZ 2.8 +/- 1.2, CBZ-CR 3.8 +/- 0.9; P less than 0.05) during the CBZ-CR treatment phase. 3. Diurnal fluctuations (CBZ 41 +/- 3%, CBZ-CR 28 +/- 2%, P less than 0.01) and variations (CBZ 53 +/- 5%, CBZ-CR 33 +/- 3%; P less than 0.01) in serum CBZ concentration were substantially less with CBZ-CR and were similar to those calculated during a 6 or 8 hourly dosage interval with conventional CBZ (fluctuation 33 +/- 3%, variation 42 +/- 5%).(ABSTRACT TRUNCATED AT 250 WORDS)