Genotoxic evaluation for the tricyclic antidepressant drug,amitriptyline

Tryptizol^® [amitriptyline HCl (AT); El-Kahira Pharmacological and Chemical Co., Cairo, Egypt], a widely used antidepressant drug in Egypt, was evaluated for its genotoxicity. The evaluation was performed in somatic (bone marrow) and germ (spermatocytes) cells, as well as well as the sperm morphology (i.e., head and tail) and count of the resulting sperm. Three doses were tested (low, medium, and high); they were chosen according to the drug manufacturer. The low-dose group received orally 1?mg/kg body weight (b.w.) daily for a total period of 1 month; the medium-dose group received 1?mg/kg b.w. daily for 15 days and 2?mg/kg b.w. daily for another 15 days; and the high-dose group received 1?mg/kg b.w. daily for 10 days, then 2?mg/kg b.w. daily for another 10 days and, finally, 4?mg/kg b.w. daily for 10 more days. The results showed that AT treatment induced structural and numerical chromosome abnormalities in somatic cells (bone marrow) and germ cells (spermatocytes). Moreover, AT significantly reduced both the mitotic index and meiotic activity after the different treatments used. AT was found to increase significantly the incidence of sperm-cell head and tail abnormalities. The sperm-cell count was also significantly decreased with the 3 doses tested. In general, results of chromosome abnormalities in both somatic and germ cells as well as sperm morphology and count showed that the effect of AT was dose dependent. The results of the current study showed that AT is a genotoxic agent for both somatic and germ cells and should be taken under special precautions and medical supervision.     

Genotoxic evaluation for the tricyclic antidepressant drug, amitriptyline

Tryptizol(?) [amitriptyline HCl (AT); El-Kahira Pharmacological and Chemical Co., Cairo, Egypt], a widely used antidepressant drug in Egypt, was evaluated for its genotoxicity. The evaluation was performed in somatic (bone marrow) and germ (spermatocytes) cells, as well as well as the sperm morphology (i.e., head and tail) and count of the resulting sperm. Three doses were tested (low, medium, and high); they were chosen according to the drug manufacturer. The low-dose group received orally 1?mg/kg body weight (b.w.) daily for a total period of 1 month; the medium-dose group received 1?mg/kg b.w. daily for 15 days and 2?mg/kg b.w. daily for another 15 days; and the high-dose group received 1?mg/kg b.w. daily for 10 days, then 2?mg/kg b.w. daily for another 10 days and, finally, 4?mg/kg b.w. daily for 10 more days. The results showed that AT treatment induced structural and numerical chromosome abnormalities in somatic cells (bone marrow) and germ cells (spermatocytes). Moreover, AT significantly reduced both the mitotic index and meiotic activity after the different treatments used. AT was found to increase significantly the incidence of sperm-cell head and tail abnormalities. The sperm-cell count was also significantly decreased with the 3 doses tested. In general, results of chromosome abnormalities in both somatic and germ cells as well as sperm morphology and count showed that the effect of AT was dose dependent. The results of the current study showed that AT is a genotoxic agent for both somatic and germ cells and should be taken under special precautions and medical supervision.     

The assessment of potential drug interactions with a new tricyclic antidepressant drug

1 Methods for the investigation of possible interactions with tricyclic antidepressant drugs are described. These methods have been applied to a new compound, Ciba 34276-Ba, which has been shown to have antidepressant activity.

2 In five normal volunteers tested before and during treatment with Ciba 34276-Ba, no abnormalities of resting or post-exercise electrocardiographs occurred. A three-fold reduction in tyramine-responsiveness was seen in three normal subjects studied, but no potentiation of the noradrenaline pressor effect occurred. One of six patients given Ciba 34276-Ba whilst on long-term treatment with bethanidine showed loss of blood pressure control.

3 The metabolic clearance of antipyrine was unaltered in two subjects studied, showing no evidence of induction or inhibition of hepatic microsomal oxidizing enzymes by Ciba 34276-Ba.

     

Circulatory effects in man of nortriptyline,a tricyclic antidepressant drug

Summary In 40 depressed patients treated with 25 or 50 mg nortriptyline (NT) t. i. d. for 3 weeks the following circulatory variables were observed prior to and during drug therapy: heart rate and blood pressure at rest (in supine and standing positions), working capacity, ECG at rest and during exercise on a bicycle ergometer. During administration of NT the heart rate increased significantly at rest in both supine and standing positions, but the orthostatic heart rate reaction remained unchanged. Diastolic blood pressure in the supine position rose slightly; in the standing position the pretreatment increase in diastolic pressure was abolished. The positive chronotropic effect did not correlate with the steady-state plasma level of NT. In one patient on NT a right bundle branch block appeared during the work test; in the remaining 39 patients the ECG records at rest and during exercise showed no adverse effects of NT.     

Therapeutic tricyclic antidepressant drug monitoring in younger and older depressive patients

The present study shows the evaluation of clinical state and serum level of tricyclic antidepressants in thirty-eight depressive younger and elderly patients during 8-week observation. We observed no statistically significant differences, neither in psychometric scale scores nor in drug serum levels in both groups of patients.     

Electrocardiographic abnormalities in acute heroin overdosage

Twenty-one 25 acutely overdosed heroin addicts had abnormalities noted on their admission electrocardiograms. The most common findings were nonspecific ST-T changes in 17 patients, sinus tachycardia in 11, and left or right atrial enlargement in 8. Five patients had more serious arrhythmias (4 atrial fibrillation and 1 ventricular tachycardia). For the entire group the initial PaO2 was 74.8 +/- 48.2 torr. This degree of oxygenation was only achieved with the use of high dose supplemental oxygen. The 5 patients with the more serious arrhythmias had comparable PaO2s but this was only achieved with higher supplemental oxygen concentrations. We conclude that electrocardiographic alterations (other than arrhythmias) are very common in acute heroin overdosage and may be related to hypoxemia. The abnormal cardiac rhythms may be due to the direct effects of heroin or its metabolites. Heroin addiction is associated with a multitude of medical complications which can affect various organ systmes including the heart (1). Within the last six years several reports have appeared documenting electrocardiographic abnormalities in heroin users (2-5). These studies dealt with either a small series of patients or patients who used methadone or heroin in a chronic fashion. No one, to our knowledge, has extensively studied the electrocardiographic changes which occur in patients with acute heroin overdosage. This retrospective analysis of the electrocardiograms (ECG), arterial blood gases and selected electrolytes in 25 consecutively hospitalized patients acutely overdosed on heroin is an attempt to correct this deficiency.     

The incidence of seizures during tricyclic antidepressant drug treatment in a brain-injured population

Tricyclic antidepressants (TCAs) have been associated with the occurrence of seizures both with overdoses and with therapeutic doses. Seizures with therapeutic doses of TCA have been reported in patients both with and without previous histories of seizures. The incidence of seizures possibly precipitated by TCAs was examined retrospectively in a population of 68 severely brain-injured patients, all of whom were at high risk for the development of seizures. Seizure histories, anticonvulsant use, comedication use, and other pertinent data were recorded before, during, and after TCA use. We conclude that 14 patients (19%) developed seizures largely caused by TCAs. Other possible contributing factors, clinical outcomes, and some recommendations are discussed.     

Ring flexibility within tricyclic antidepressant drugs

The internal flexibility of the central seven-membered ring of a series of tricyclic antidepressant drugs (TCAs), imipramine [1], amitriptyline [2], doxepin [3], and dothiepin [4], has been investigated by (1)H and (13)C nuclear magnetic (NMR) techniques. Two dynamic processes were examined: ring inversion and bridge flexing. (1)H NMR line-shape analysis was used to obtain ring inversion barriers for 2-4. These studies yielded energy barriers of 14.3, 16.7, and 15.7 +/- 0.6 kcal/mol for the hydrochloride salts of doxepin, dothiepin, and amitriptyline, respectively. The barriers for the corresponding free bases were lower by 0.6 kcal/mol on average. (13)C T(1) relaxation measurements were used to determine the degree of bridge flexing associated with the central seven-membered ring for all four compounds. By fitting the T(1) data to a two-state jump model, lifetimes and amplitudes of rapid bridge flexing motions were determined. The results show that imipramine has the fastest rate of bridge flexing, followed by amitriptyline, doxepin, and dothiepin. The pharmacological profiles of the TCAs are complex and they interact with many receptor sites, resulting in numerous side effects and a general lack of understanding of their precise mode of action in different anxiety-related disorders. They all have similar three-dimensional structures, which makes it difficult to rationalize their differing relative potency in different assays/clinical settings. However, the clear finding here that there are significantly different degrees of internal mobility suggests that molecular dynamics should be an additional factor considered when trying to understand the mode of action of this clinically important family of molecules.     

Clomipramine: an antiobsessional tricyclic antidepressant

The chemistry, pharmacology, pharmacokinetics, adverse effects, and dosage of clomipramine hydrochloride are described, and clinical studies of the use of clomipramine in treating obsessive-compulsive disorder (OCD), other psychiatric conditions, and chronic pain are reviewed. Clomipramine hydrochloride, a tricyclic antidepressant, is a potent inhibitor of serotonin reuptake and may affect dopaminergic neurotransmission, suppress rapid eye movement sleep, produce changes in electrocardiograms, and elevate plasma prolactin. The drug is well absorbed from the gastrointestinal tract and undergoes extensive first-pass metabolism. Peak plasma concentrations occur three to four hours after a 150-mg oral dose. The mean elimination half-life is 39 hours. Some 66% of a dose is excreted in the urine, the remainder being eliminated in the feces. In clinical trials, clomipramine was significantly more effective than placebo, clorgiline, amitriptyline, imipramine, and doxepin in ameliorating the symptoms of OCD. Initial effects are seen at four weeks; improvement may continue for up to 18 weeks. Clomipramine may also be effective in treating panic attacks, phobias, depression, and chronic pain. The most common adverse effects of clomipramine are anticholinergic; others include nausea, seizures, and sexual difficulties. Interactions between clomipramine and barbiturates, haloperidol, monoamine oxidase inhibitors, and cigarette smoking have been documented. The usual initial adult dosage is 25-50 mg/day, titrated gradually to 250 mg/day if necessary. Clomipramine hydrochloride is a welcome new agent for the treatment of obsessive-compulsive disorder. Although its adverse-effect profile is like that of other tricyclic antidepressants, sexual dysfunction and seizures may be more frequent with this agent and limit its use.     

Interpreting tricyclic antidepressant measurements in urine in an emergency department setting: comparison of two qualitative point-of-care urine tricyclic antidepressant drug immunoassays with quantitative serum chromatographic analysis

Patients taking tricyclic antidepressants (TCA) can experience toxicity or severe side effects. As a rapid and less technically demanding alternative to quantitative serum analysis, most laboratories offer qualitative immunoassays to assist in the evaluation of a suspected TCA overdose. However, the relationship between quantitative serum and qualitative urine levels of TCA-related compounds and their metabolites has not been comprehensively studied. Serum high-performance liquid chromatography results were compared to the qualitative urine results using the Syva Rapid Test and the Biosite Triage. Serum concentrations of amitriptyline, desipramine, doxepin, imipramine, and nortriptyline ranging from subtherapeutic to toxic triggered a positive response on both urine immunoassay devices. On the other hand, neither immunoassay uniformly detected clomipramine, even at serum levels greater than the therapeutic range. False positives due to cyclobenzaprine were more common with the Biosite assay. For virtually all positive urine TCA findings, it was not possible to determine whether the positive results corresponded to subtherapeutic, therapeutic, supratherapeutic, or toxic serum concentrations. Because urine immunoassays are the only option for many laboratories analyzing specimens for TCAs (especially in an emergency setting), clinicians must understand the limitations and interpret results in conjunction with clinical findings and/or quantitation of serum levels.     

Predicting severity of tricyclic antidepressant overdose.

The measurement of plasma concentration, a prolonged QRS interval, and level of consciousness have all been recommended as useful indicators of toxicity following tricyclic antidepressant overdose. The aims of this study were firstly, to determine the relative prognostic value of each of these indicators and secondly, to assess when a patient can be discharged safely from the intensive care unit. Data were evaluated on 67 patients with tricyclic antidepressant overdose from four centers. Plasma tricyclic antidepressant concentrations were measured, coma grade was evaluated using the Matthew-Lawson Coma Scale and a ECG was obtained from 23 patients on admission. Complications such as convulsions, hypotension, arrhythmias, and need for intubation and ventilation were recorded. Thirty patients developed complications and no patient died. Coma grade was the best predictor of outcome. The development of serious complications is unlikely in patients whose level of consciousness is grade II or less and who are admitted to hospital more than 6 h after overdose. Plasma tricyclic antidepressant concentration was of no additional value in predicting toxic complications or deciding when the patient could leave the intensive care unit. Our study suggests that an alert and orientated patient with a QRS duration less than 100 ms is the best indicator for safe transfer to a medical or psychiatric ward.     

Pulmonary consequences of severe tricyclic antidepressant ingestion

We prospectively studied 56 consecutive patients with severe tricyclic antidepressant ingestion to determine the incidence of associated pulmonary complications. Among the patients meeting the entrance criteria, the mean antidepressant level was 1136 ng/ml. Other characteristics were a QRS duration of greater than or equal to 0.1 seconds in 35 (63%) and seizures in 19 (34%). Seventeen patients (30%) developed 18 abnormal chest X-ray findings which included pulmonary edema in 8 cases and aspiration pneumonia in 10. Using logistic regression, we evaluated the influence of tricyclic antidepressant level, blood pressure, QRS interval, seizures, drug co-ingestion and the use of gastric lavage vs. ipecac-induced emesis on pulmonary complications. For patients with pulmonary edema, the only significantly associated factor was hypotension on emergency department presentation. For aspiration pneumonia, no significant associations were found. Co-ingestion of another drug had no apparent influence on the development of pulmonary abnormalities. Our findings suggest that pulmonary edema and aspiration pneumonia are frequent complications of severe ingestions of tricyclic antidepressants. Pulmonary edema appears to result from hypotension or its treatment. The etiology of aspiration pneumonia is unclear. A chest X-ray should be obtained in all victims of tricyclic antidepressant overdose.