The development of a potentially life-threatening serotonin syndrome has been reported with SNRIs and SSRIs, including clomipramine hydrochloride, alone but particularly with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, tryptophan, buspirone, and St. John’s Wort) and with drugs that impair metabolism of serotonin (in particular, MAOIs, both those intended to treat psychiatric disorders and also others, such as linezolid and intravenous methylene blue).
Serotonin syndrome symptoms may include mental status changes (e.g., agitation, hallucinations, delirium, and coma), autonomic instability (e.g., tachycardia, labile blood pressure, dizziness, diaphoresis, flushing, hyperthermia), neuromuscular changes (e.g., tremor, rigidity, myoclonus, hyperreflexia, incoordination), seizures, and/or gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea). Patients should be monitored for the emergence of serotonin syndrome.
The concomitant use of clomipramine hydrochloride with MAOIs intended to treat psychiatric disorders is contraindicated. Clomipramine hydrochloride should also not be started in a patient who is being treated with MAOIs such as linezolid or intravenous methylene blue. All reports with methylene blue that provided information on the route of administration involved intravenous administration in the dose range of 1 mg/kg to 8 mg/kg. No reports involved the administration of methylene blue by other routes (such as oral tablets or local tissue injection) or at lower doses. There may be circumstances when it is necessary to initiate treatment with an MAOI such as linezolid or intravenous methylene blue in a patient taking clomipramine hydrochloride. Clomipramine hydrochloride should be discontinued before initiating treatment with the MAOI (see CONTRAINDICATIONSand DOSAGE AND ADMINISTRATION).
If concomitant use of clomipramine hydrochloride with other serotonergic drugs, including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, buspirone, tryptophan, and St. John’s Wort is clinically warranted, patients should be made aware of a potential increased risk for serotonin syndrome, particularly during treatment initiation and dose increases.
Treatment with clomipramine hydrochloride and any concomitant serotonergic agents should be discontinued immediately if the above events occur and supportive symptomatic treatment should be initiated.
The pupillary dilation that occurs following use of many antidepressant drugs including clomipramine hydrochloride may trigger an angle closure attack in a patient with anatomically narrow angles who does not have a patent iridectomy.
During premarket evaluation, seizure was identified as the most significant risk of clomipramine hydrochloride use.
The observed cumulative incidence of seizures among patients exposed to clomipramine hydrochloride at doses up to 300 mg/day was 0.64% at 90 days, 1.12% at 180 days, and 1.45% at 365 days. The cumulative rates correct the crude rate of 0.7% (25 of 3,519 patients) for the variable duration of exposure in clinical trials.
Although dose appears to be a predictor of seizure, there is a confounding of dose and duration of exposure, making it difficult to assess independently the effect of either factor alone. The ability to predict the occurrence of seizures in subjects exposed to doses of CMI greater than 250 mg is limited, given that the plasma concentration of CMI may be dose-dependent and may vary among subjects given the same dose. Nevertheless, prescribers are advised to limit the daily dose to a maximum of 250 mg in adults and 3 mg/kg (or 200 mg) in children and adolescents (see DOSAGE AND ADMINISTRATION).
Caution should be used in administering clomipramine hydrochloride to patients with a history of seizures or other predisposing factors, e.g., brain damage of varying etiology, alcoholism, and concomitant use with other drugs that lower the seizure threshold.
Rare reports of fatalities in association with seizures have been reported by foreign postmarketing surveillance, but not in U.S. clinical trials. In some of these cases, clomipramine hydrochloride had been administered with other epileptogenic agents; in others, the patients involved had possibly predisposing medical conditions. Thus a causal association between clomipramine hydrochloride treatment and these fatalities has not been established.
Physicians should discuss with patients the risk of taking clomipramine hydrochloride while engaging in activities in which sudden loss of consciousness could result in serious injury to the patient or others, e.g., the operation of complex machinery, driving, swimming, climbing.
Rare cases of drug rash with eosinophilia and systemic symptoms (DRESS) have been reported with the use of clomipramine. In the event of severe acute reactions such as DRESS, discontinue clomipramine therapy immediately and institute appropriate treatment.
Since depression is a commonly associated feature of OCD, the risk of suicide must be considered. Prescriptions for clomipramine hydrochloride should be written for the smallest quantity of capsules consistent with good patient management, in order to reduce the risk of overdose.
Modest orthostatic decreases in blood pressure and modest tachycardia were each seen in approximately 20% of patients taking clomipramine hydrochloride in clinical trials; but patients were frequently asymptomatic. Among approximately 1,400 patients treated with CMI in the premarketing experience who had ECGs, 1.5% developed abnormalities during treatment, compared with 3.1% of patients receiving active control drugs and 0.7% of patients receiving placebo. The most common ECG changes were PVCs, ST-T wave changes, and intraventricular conduction abnormalities. These changes were rarely associated with significant clinical symptoms. Nevertheless, caution is necessary in treating patients with known cardiovascular disease, and gradual dose titration is recommended.
Psychosis, Confusion, and Other Neuropsychiatric Phenomena
Patients treated with clomipramine hydrochloride have been reported to show a variety of neuropsychiatric signs and symptoms including delusions, hallucinations, psychotic episodes, confusion, and paranoia. Because of the uncontrolled nature of many of the studies, it is impossible to provide a precise estimate of the extent of risk imposed by treatment with clomipramine hydrochloride. As with tricyclic antidepressants to which it is closely related, clomipramine hydrochloride may precipitate an acute psychotic episode in patients with unrecognized schizophrenia.
During premarketing testing of clomipramine hydrochloride in patients with affective disorder, hypomania or mania was precipitated in several patients. Activation of mania or hypomania has also been reported in a small proportion of patients with affective disorder treated with marketed tricyclic antidepressants, which are closely related to clomipramine hydrochloride.
During premarketing testing, clomipramine hydrochloride was occasionally associated with elevations in SGOT and SGPT (pooled incidence of approximately 1% and 3%, respectively) of potential clinical importance (i.e., values greater than 3 times the upper limit of normal). In the vast majority of instances, these enzyme increases were not associated with other clinical findings suggestive of hepatic injury; moreover, none were jaundiced. Rare reports of more severe liver injury, some fatal, have been recorded in foreign postmarketing experience. Caution is indicated in treating patients with known liver disease, and periodic monitoring of hepatic enzyme levels is recommended in such patients.
Although no instances of severe hematologic toxicity were seen in the premarketing experience with clomipramine hydrochloride, there have been postmarketing reports of leukopenia, agranulocytosis, thrombocytopenia, anemia, and pancytopenia in association with clomipramine hydrochloride use. As is the case with tricyclic antidepressants to which clomipramine hydrochloride is closely related, leukocyte and differential blood counts should be obtained in patients who develop fever and sore throat during treatment with clomipramine hydrochloride.
Central Nervous System
More than 30 cases of hyperthermia have been recorded by nondomestic postmarketing surveillance systems. Most cases occurred when clomipramine hydrochloride was used in combination with other drugs. When clomipramine hydrochloride and a neuroleptic were used concomitantly, the cases were sometimes considered to be examples of a neuroleptic malignant syndrome.
The rate of sexual dysfunction in male patients with OCD who were treated with clomipramine hydrochloride in the premarketing experience was markedly increased compared with placebo controls (i.e., 42% experienced ejaculatory failure and 20% experienced impotence, compared with 2.0% and 2.6%, respectively, in the placebo group). Approximately 85% of males with sexual dysfunction chose to continue treatment.
Hyponatremia has occurred as a result of treatment with clomipramine. In many cases, hyponatremia appears to be the result of the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Elderly patients may be at greater risk of developing hyponatremia with a serotonergic antidepressant. Also, patients taking diuretics or who are otherwise volume-depleted can be at greater risk. Discontinuation of clomipramine hydrochloride in patients with symptomatic hyponatremia and appropriate medical intervention should be instituted. Signs and symptoms of hyponatremia include headache, difficulty concentrating, memory impairment, confusion, weakness, and unsteadiness, which can lead to falls. More severe and/or acute cases have included hallucination, syncope, seizure, coma, respiratory arrest, and death.
In controlled studies of OCD, weight gain was reported in 18% of patients receiving clomipramine hydrochloride, compared with 1% of patients receiving placebo. In these studies, 28% of patients receiving clomipramine hydrochloride had a weight gain of at least 7% of their initial body weight, compared with 4% of patients receiving placebo. Several patients had weight gains in excess of 25% of their initial body weight. Conversely, 5% of patients receiving clomipramine hydrochloride and 1% receiving placebo had weight losses of at least 7% of their initial body weight.
As with closely related tricyclic antidepressants, concurrent administration of clomipramine hydrochloride with electroconvulsive therapy may increase the risks; such treatment should be limited to those patients for whom it is essential, since there is limited clinical experience.
Prior to elective surgery with general anesthetics, therapy with clomipramine hydrochloride should be discontinued for as long as is clinically feasible, and the anesthetist should be advised.
Use in Concomitant Illness
As with closely related tricyclic antidepressants, clomipramine hydrochloride should be used with caution in the following:
- Hyperthyroid patients or patients receiving thyroid medication, because of the possibility of cardiac toxicity;
- Patients with increased intraocular pressure, a history of narrow-angle glaucoma, or urinary retention, because of the anticholinergic properties of the drug;
- Patients with tumors of the adrenal medulla (e.g., pheochromocytoma, neuroblastoma) in whom the drug may provoke hypertensive crises;
- Patients with significantly impaired renal function.
A variety of withdrawal symptoms have been reported in association with abrupt discontinuation of clomipramine hydrochloride, including dizziness, nausea, vomiting, headache, malaise, sleep disturbance, hyperthermia, and irritability. In addition, such patients may experience a worsening of psychiatric status. While the withdrawal effects of clomipramine hydrochloride have not been systematically evaluated in controlled trials, they are well known with closely related tricyclic antidepressants, and it is recommended that the dosage be tapered gradually and the patient monitored carefully during discontinuation (see DRUG ABUSE AND DEPENDENCE).
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