Imipramine and seizures

Outside the box: Medications worth considering when traditional antiepileptic drugs have failed

PURPOSE

Review and discuss medications efficacious for seizure control, despite primary indications for other diseases, as treatment options in patients who have failed therapy with traditional antiepileptic drugs (AEDs).

METHODS

Literature searches were conducted utilizing PubMed and MEDLINE databases employing combinations of search terms including, but not limited to, "epilepsy", "refractory", "seizure", and the following medications: acetazolamide, amantadine, bumetanide, imipramine, lidocaine, verapamil, and various stimulants.

RESULTS

Data from relevant case studies, retrospective reviews, and available clinical trials were gathered, analyzed, and reported. Experience with acetazolamide, amantadine, bumetanide, imipramine, lidocaine, verapamil, and various stimulants show promise for cases of refractory epilepsy in both adults and children. Many medications lack large scale, randomized clinical trials, but the available data is informative when choosing treatment for patients that have failed traditional epilepsy therapies.

CONCLUSIONS

All neurologists have encountered a patient that failed nearly every AED, diet, and surgical option. For these patients, we often seek fortuitous discoveries within small series and case reports, hoping to find a treatment that might help the patient. In the present review, we describe medications for which antiepileptic effect has been ascribed after they were introduced for other indications.

Tricyclic antidepressant poisoning: an evidence-based consensus guideline for out-of-hospital management

A review of U.S. poison center data for 2004 showed over 12,000 exposures to tricyclic antidepressants (TCAs). A guideline that determines the conditions for emergency department referral and prehospital care could potentially optimize patient outcome, avoid unnecessary emergency department visits, reduce healthcare costs, and reduce life disruption for patients and caregivers. An evidence-based expert consensus process was used to create the guideline. Relevant articles were abstracted by a trained physician researcher. The first draft of the guideline was created by the lead author. The entire panel discussed and refined the guideline before distribution to secondary reviewers for comment. The panel then made changes based on the secondary review comments. The objective of this guideline is to assist poison center personnel in the appropriate prehospital triage and management of patients with suspected ingestions of TCAs by 1) describing the manner in which an ingestion of a TCA might be managed, 2) identifying the key decision elements in managing cases of TCA ingestion, 3) providing clear and practical recommendations that reflect the current state of knowledge, and 4) identifying needs for research. This guideline applies to ingestion of TCAs alone. Co-ingestion of additional substances could require different referral and management recommendations depending on their combined toxicities. This guideline is based on the assessment of current scientific and clinical information. The panel recognizes that specific patient care decisions may be at variance with this guideline and are the prerogative of the patient and the health professionals providing care, considering all the circumstances involved. This guideline does not substitute for clinical judgment. Recommendations are in chronological order of likely clinical use. The grade of recommendation is in parentheses. 1) Patients with suspected self-harm or who are the victims of malicious administration of a TCA should be referred to an emergency department immediately (Grade D). 2) Patients with acute TCA ingestions who are less than 6 years of age and other patients without evidence of self-harm should have further evaluation including standard history taking and determination of the presence of co-ingestants (especially other psychopharmaceutical agents) and underlying exacerbating conditions, such as convulsions or cardiac arrhythmias. Ingestion of a TCA in combination with other drugs might warrant referral to an emergency department. The ingestion of a TCA by a patient with significant underlying cardiovascular or neurological disease should cause referral to an emergency department at a lower dose than for other individuals. Because of the potential severity of TCA poisoning, transportation by EMS, with close monitoring of clinical status and vital signs en route, should be considered (Grade D). 3) Patients who are symptomatic (e.g., weak, drowsy, dizzy, tremulous, palpitations) after a TCA ingestion should be referred to an emergency department (Grade B). 4) Ingestion of either of the following amounts (whichever is lower) would warrant consideration of referral to an emergency department: an amount that exceeds the usual maximum single therapeutic dose or an amount equal to or greater than the lowest reported toxic dose. For all TCAs except desipramine, nortriptyline, trimipramine, and protriptyline, this dose is >5 mg/kg. For despiramine it is >2.5 mg/kg; for nortriptyline it is >2.5 mg/kg; for trimipramine it is >2.5 mg/kg; and for protriptyline it is >1 mg/kg. This recommendation applies to both patients who are naïve to the specific TCA and to patients currently taking cyclic antidepressants who take extra doses, in which case the extra doses should be added to the daily dose taken and then compared to the threshold dose for referral to an emergency department (Grades B/C). 5) Do not induce emesis (Grade D). 6) The risk-to-benefit ratio of prehospital activated charcoal for gastrointestinal decontamination in TCA poisoning is unknown. Prehospital activated charcoal administration, if available, should only be carried out by health professionals and only if no contraindications are present. Do not delay transportation in order to administer activated charcoal (Grades B/D). 7) For unintentional poisonings, asymptomatic patients are unlikely to develop symptoms if the interval between the ingestion and the initial call to a poison center is greater than 6 hours. These patients do not need referral to an emergency department facility (Grade C). 8) Follow-up calls to determine the outcome for a TCA ingestions ideally should be made within 4 hours of the initial call to a poison center and then at appropriate intervals thereafter based on the clinical judgment of the poison center staff (Grade D). 9) An ECG or rhythm strip, if available, should be checked during the prehospital assessment of a TCA overdose patient. A wide-complex arrhythmia with a QRS duration longer than 100 msec is an indicator that the patient should be immediately stabilized, given sodium bicarbonate if there is a protocol for its use, and transported to an emergency department (Grade B). 10) Symptomatic patients with TCA poisoning might require prehospital interventions, such as intravenous fluids, cardiovascular agents, and respiratory support, in accordance with standard ACLS guidelines (Grade D). 11) Administration of sodium bicarbonate might be beneficial for patients with severe or life-threatening TCA toxicity if there is a prehospital protocol for its use (Grades B/D). 12) For TCA-associated convulsions, benzodiazepines are recommended (Grade D). 13) Flumazenil is not recommended for patients with TCA poisoning (Grade D).

The serotonergic and noradrenergic effects of antidepressant drugs are anticonvulsant, not proconvulsant

Contrary to existing evidence, convulsant liability of the antidepressants has been attributed to noradrenergic and serotonergic increments. This is a classic case of confusing treatment effects with the manifestations of illness. In fact, the remarkable anticonvulsant effectiveness of antidepressant-induced noradrenergic and serotonergic activation has been ignored. Some antidepressant drugs such as the specific serotonin reuptake inhibitor (SSRI) fluoxetine may be devoid of convulsant liability entirely, while having distinct anticonvulsant properties. Some authorities advance the notion that the seizure predisposition of patients with epilepsy increases risks for antidepressant-induced seizures. However, evidence does not support this contention. Instead, data increasingly support the concept that noradrenergic and serotonergic deficiencies contribute to seizure predisposition. Indeed, the antidepressants have the potential to overcome seizure predisposition in epilepsy. Whereas therapeutic doses of antidepressants elevate noradrenergic and serotonergic transmission, larger doses can activate other biological processes that may be convulsant.

Pharmacological treatment of depression in children and adolescents

Major depression is a common disorder during childhood and adolescence. Over the past decade, many new antidepressants have been marketed in the US. In adults, these newer agents have been shown to be as effective as the prototypic tricyclic antidepressants (TCAs). Further, when compared with the TCAs these medications are better tolerated and are safer in overdose. Although TCAs are effective in the treatment of depressed adults, controlled clinical trials have not demonstrated their efficacy in either children or adolescents. In addition, concerns about the safety of TCAs and the monoamine oxidase inhibitors has left disappointingly few pharmacological treatment options available for depressed children and adolescents. For this reason, clinicians have begun to prescribe the newer agents for this population, despite the fact that relatively little is known about their disposition, safety or effectiveness in the young. Investigators have begun to examine whether the use of newer antidepressant medications such as fluoxetine, sertraline, paroxetine, fluvoxamine, nefazodone, and venlafaxine is truly indicated for children and adolescents with major depression. Pharmacokinetic studies of sertraline, paroxetine and nefazodone have been performed in depressed youths. The results of these studies have provided data for rational administration strategies for these agents. They have also provided evidence that these agents may be well tolerated in children and adolescents. Further evidence that these agents are often well tolerated when prescribed to depressed youths has been obtained from both open-label and double-blind studies. Published studies have generally shown that open-label treatment with these newer agents often leads to symptom amelioration in paediatric patients with major depression. Since high rates of placebo response are often seen in depressed children and adolescents, results from these studies cannot be interpreted to suggest that these medications have true antidepressant efficacy in this population. At present, the results of only two such studies have been published. The results of one of these trials are difficult to interpret because of methodological considerations. The other study reported that treatment with fluoxetine was superior to placebo. This paper critically reviews what has been published about the pharmacological treatment of depressed paediatric patients and provides some guidance to the use of antidepressants in this patient population, paying particular attention to what is known about the newer antidepressants as well as considering directions for future research.

A pilot study of clomipramine in young autistic children

OBJECTIVE

To assess the short-term efficacy and safety of clomipramine in hospitalized young children with autism.

METHOD

This was an open pilot study; after a 1-week placebo baseline, subjects were treated with clomipramine for 5 weeks. Dosage was individually regulated; starting dose was 25 mg/day; increments were 25 mg/day. Maximum dose was 250 mg/day or 5.0 mg/kg per day, whichever was less. Multiple raters, under several conditions, used the Children's Psychiatric Rating Scale, Clinical Global Impressions, Conners Parent Teacher Questionnaire, and the Clinical Global Consensus Ratings.

RESULTS

Eight children, aged 3.5 to 8.7 years, were enrolled in the study; seven of these completed the study. A 3.5-year-old boy was excluded during the third week of treatment after having urinary retention on two occasions. At doses ranging from 2.50 to 4.64 mg/kg per day (mean = 3.14), one child improved moderately and six were rated as worse on the Clinical Global Consensus Ratings. Untoward effects were common. CONCLUSIONS; Clomipramine was not therapeutic and was associated with serious untoward effects in this sample. Young autistic children may be more prone to experience untoward effects than older patients.

Side effects of methylphenidate and desipramine alone and in combination in children

OBJECTIVE

To investigate side effects of methylphenidate and desipramine alone and in combination in hospitalized children with symptoms of attention-deficit hyperactivity disorder and depression.

METHOD

A double-blind placebo controlled crossover design was used to investigate each medication alone and in combination. Side effect ratings and EKGs were done weekly. Pulse and blood pressure were monitored daily.

RESULTS

Nausea, dry mouth, and tremor were present in at least twice as many children on combined methylphenidate and desipramine compared with any other condition. Nausea/vomiting, headaches, other aches, refusal of food, and feeling "tired" were significantly more frequent during the combined methylphenidate plus desipramine condition when compared with either methylphenidate alone or with baseline. Significantly higher ventricular heart rate was found on combined methylphenidate plus desipramine compared with desipramine alone, methylphenidate alone, and baseline. Prolonged PR interval and significantly higher heart rate occurred during desipramine alone compared with baseline.

CONCLUSIONS

During the several-month duration of the study, there were more frequent side effects during combined methylphenidate plus desipramine treatment than with either medication alone. Clinically, side effects present during combined medication appeared to be similar to and no more serious than those associated with desipramine alone.

Diagnostic and assessment issues related to pharmacotherapy for children and adolescents with autism

Autism involves not only developmental delays but also aberrant behavior, both of which change in nature over time. Rating instruments may be useful to assess maladaptive and adaptive behaviors of autistic children in a standardized way and, perhaps, to measure change due to treatment. With the expansion of basic science, knowledge, and technology, there is increasing evidence that autism is etiologically heterogeneous. Currently, there is no biological marker specific to autism, although hyperserotonemia is a consistent finding in one third of autistic children. An aim of basic science research has been to develop a rational pharmacotherapy based upon the underlying neurochemistry. However, at the present time, this approach has not always been successful. It is expected that the development and use of more restrictive criteria, delineation of subtypes of autism, and interaction of descriptive, behavioral, clinical, and basic research will lead to more effective planning for treatment. The relationship of assessment to treatment response is presented and discussed.

Psychoactive agents, seizure production, and sudden death in epilepsy

Major tranquilizers as well as antidepressant agents have been associated with clinical seizures in patients administered these agents. The incidence of such seizures is generally low when these drugs are administered in therapeutic doses. However, administration of large doses of these agents has been associated with many cases of convulsion production. The effects that these drugs have on animal models of epilepsy have been examined. It appears that the phenothiazines act as convulsant agents at lower doses, whereas, at higher doses, they act as anticonvulsant drugs. Antidepressants, on the other hand, appear to exert an anticonvulsant effect at low doses and convulsant effects at high doses. The mechanism by which these agents alter the seizure threshold is not yet known. Clinically, drugs of lower seizure production potential should be substituted for those drugs with greater potential in treating epileptic patients for psychiatric ailments. The problem of sudden death in epileptic patients is one that must be confronted. Sudden death has most frequently been attributed to autonomic dysfunction and cardiac arrhythmia in these patients. The contribution of stress in sudden death production also must be taken into account. In addition, some psychoactive agents have been associated with sudden death as well as cardiac arrhythmia and seizure production. Thus, in light of the possible additivity of the factors involved in the production of sudden death, the administration of a psychoactive agent to an epileptic patient should be approached with caution. Those agents that do not alter cardiac rhythm or seizure threshold should be administered if a psychoactive agent is deemed necessary for the management of psychiatric illness in the epileptic patient.

Preliminary study of imipramine in profoundly retarded residents

This was a double-blind, placebo-controlled crossover trial of imipramine (3 mg/kg/day) in 10 profoundly retarded residents. Two groups were formulated: one with depressivelike (or affective) symptoms and one with acting-out behaviors. Measures of drug response included ratings of ward behavior using the Aberrant Behavior Checklist, interval samples of behavior in the living units, and observations of behavior in a playroom situation. Results indicated that the drug caused behavioral deterioration in the Irritability, Lethargy/social withdrawal, and Hyperactivity dimensions of the rating scale, irrespective of subgroup. In addition, gross motor activity was significantly increased on the wards due to imipramine, and it was found that the affective group became less active and the acting-out group more active during free play. Physical side effects were uncommon. These unexpected adverse behavioral effects were discussed with respect to dosage and diagnostic considerations.

Effect of anticonvulsant drugs on inhibitory and excitatory pathways

A conditioning stimulus to the periventricular gray matter inhibits the response of spinal trigeminal neurons to maxillary nerve stimulation. Sodium valproate and ethosuximide decrease the periventricular inhibition without significantly affecting the response of these neurons to the unconditioned maxillary nerve stimulus. We have now found that carbamazepine and phenytoin decrease the response to the unconditioned maxillary nerve stimulus, and only depress the periventricular inhibition secondarily. These results further support the hypothesis that the ability to depress selectively inhibitory pathways in the CNS is an important characteristic of antiabsence drugs, and that absence seizures may represent paroxysmal discharges in inhibitory pathways.

Ineffectiveness of imipramine in children who fail to respond to methylphenidate

Ten hyperactive children who had failed to respond to methylphenidate were treated with imipramine in a placebo-controlled, crossover design. No significant drug effects were obtained either on parent and teacher ratings of the child's behavior or on the child's performance in a laboratory measure of sustained attention. Findings suggest that imipramine has limited clinical usefulness in the treatment of hyperactive children who fail to respond to methylphenidate.

Psychopharmacological treatment of psychotic children. A survey

Controlled investigations on the psychopharmacological treatment of psychotic children are reviewed. Children with infantile autism might benefit from psychopharmacological medication when they grow older, e.g. above the age of 7 years. Learning might be facilitated when the psychoactive medication is able to inhibit psychotic preoccupations and idiosyncratic reactions. Schizophrenic and manic-depressive psychoses are rarely seen in childhood. A subgroup of the children with infantile autism might develop schizophrenic symptoms. Schizophrenia and manic-depressive psychosis in children are treated as in adults. Special caution must be paid to the toxic effects of imipramine.

Tricyclic antidepressant toxicity

Tricyclic antidepressants are dibenzazepine derivatives with adrenergic, anticholinergic, and direct cardio-depressant activity. Double-blind clinical studies show TCAD to be efficacious for two-thirds of depressed patients. Cardiac toxicity is significant, especially on diseased myocardium. Serious arrhythmias and intracardiac blocks have been reported on therapeutic doses. Tricyclic antidepressant overdose is a serious condition which is becoming progressively more common. The agents' principal toxicities are to the nervous system and the heart. The syndrome can be divided into three stages of varying severity. The vast majority of cases are in the mild Stage I. Some patients reach Stage II with major CNS effects and increasing intracardiac block. Stage III, which encompassed less than 5% of poisonings, is a potentially fatal situation with respiratory arrest, convulsions, and ventricular arrhythmias. Prevention is extremely important in poisoning therapy. Supportive measures are all that is generally needed for mild poisoning. Moderate and severe overdoses will require respiratory support, anticonvulsants, physostigmine, and beta-blockers. Cardioversion and pacing may be necessary.