Clozapine benzodiazepines

Potentially clinically significant interactions include the tendency for fluvoxamine to increase circulating concentrations of oxidatively metabolized benzodiazepines, clozapine, theophylline, and warfarin. Sertraline and fluoxetine can increase levels of benzodiazepines, clozapine, and warfarin. Paroxetine increases levels of clozapine, theophylline, and warfarin. Fluoxetine also potentiates tricyclic antidepressants and some class 1C antiarrhythmics with a narrow therapeutic index (including encainide, flecainide, and propafenone). Nefazodone potentiates benzodiazepines other than lorazepam and oxazepam. 

Occasional Confusion amnesia disinhibition paradoxical excitement depression dizziness witiidrawal symptoms, including convulsions, on abrupt discontinuance (witiidrawal may be especially difficult with alprazolam) rebound insomnia or excitement Rare Hypotension blood dyscrasias jaundice allergic reactions paradoxical rage reactions stuttering with alprazolam BUPROPION, Anxiety agitation insomnia tremor anorexia BUSPIRONE, Dizziness headache nausea paresthesias diarrhea CHLORDIAZEPOXIDE, see Benzodiazepines CHLORPROMAZINE, see Phenothiazines, aliphatic CHLORPROTHIXENE, similar to Phenothiazines CLOMIPRAMINE, see Tricyclic antidepressants CLORAZEPATE, see Benzodiazepines CLOZAPINE... 

Pharmacotherapy is the cornerstone of acute and maintenance treatment of bipolar disorder. Mood-stabilizing drugs are the usual first-choice treatments and include lithium, divalproex, carbamazepine, and lamotrigine. Atypical antipsychotics other than clozapine are also approved for treatment of acute mania. Lithium, lamotrigine, olanzapine, and aripiprazole are approved for maintenance therapy. Drugs used with less research support and without Food and Drug Administration (FDA) approval include topiramate and oxcarbazepine. Benzodiazepines are used adjunctively for mania. 

These differences may become particularly germane if co-prescribing with some antipsychotics is undertaken. For example, in certain individuals, combinations of clozapine with benzodiazepines may lead to unexpected adverse events, including delirium and augmented respiratory depression (Jackson, Markowitz Brewer-ton, 1995 Grohmann et al, 1989). Presumably if there are additive or synergistic effects of ethnicity on clearance of one or both substances, adverse events may be enhanced. Similar interactions are theoretically possible with olanzapine, as adverse interactions have been described between olanzapine and benzodiazepines, at least in the elderly (Kryzhanovskaya etal, 2006). 

Jackson, C.W., Markowitz, J. S. Brewerton, T. D. (1995). Delirium associated with clozapine and benzodiazepine combinations. Ann. Clin. Psychiatry, 7, 139—41. 

Non-motor signs of the disorder are also treatable with symptomatic medications. The frequent mood disorder can be treated with standard antidepressants, including tricyclics (such as amitryptiline) or serotonin reuptake inhibitors (SSRIs, such as fluoxetine or sertraline). This treatment is not without risks in these patients, as it may trigger manic episodes or may even precipitate suicide. Anxiety responds to benzodiazepines, as well as to effective treatment of depression. Long-acting benzodiazepines are favored over short-acting ones because of the lesser abuse potential. Some of the behavioral abnormalities may respond to treatment with the neuroleptics as well. The use of atypical neuroleptics, such as clozapine is preferred over the typical neuroleptics as they may help to control dyskinesias with relatively few extrapyramidal side-effects (Ch. 54). 

A host of medications have been nsed to treat TD including medications that block norepinephrine activity (clonidine and propranolol), dopamine-activating medications (bromocriptine), benzodiazepines, acetylcholine-activating medications, calcium channel blockers, and monoamine oxidase inhibitors. In addition, vitamin E supplementation and atypical antipsychotics including clozapine have been used to treat TD. 

Drugs that may be affected by SSRIs Drugs that may be affected by SSRIs include alcohol, benzodiazepines, beta blockers, buspirone, carbamazepine, cisapride, clozapine, cyclosporine, diltiazem, digoxin, haloperidol, hydantoins, lithium, methadone, mexiletine, nonsedating antihistamines, NSAIDs, olanzapine, phenothiazines, phenytoin, pimozide, procyclidine, ritonavir, ropivacaine, sumatriptan, sulfonylureas, sympathomimetics, tacrine, theophylline, tolbutamide, tricyclic antidepressants, and warfarin. 

Other adverse cardiovascular and respiratory effects Orthostatic hypotension, with or without syncope, can occur with clozapine treatment. Rarely, collapse can be profound and accompanied by respiratory and/or cardiac arrest. Orthostatic hypotension is more likely to occur during initial titration in association with rapid dose escalation. In patients who have had even a brief interval off clozapine, start treatment with 12.5 mg once or twice daily (see Warnings). Because collapse, respiratory arrest, and cardiac arrest during initial treatment have occurred in patients receiving benzodiazepines or other psychotropic drugs, caution is advised when clozapine is initiated in patients taking a benzodiazepine or any other psychotropic drug. 

Drugs that may interact with clozapine include caffeine, SSRIs, benzodiazepines, risperidone, CYP1A2 induces/inhibitors, CYP3A4 inhibitors, phenobarbital, and ritonavir. 

Smoking cessation, with or without nicotine substitutes, may alter response to concomitant medication in ex-smokers. Smoking may affect alcohol, benzodiazepines, beta-adrenergic blockers, caffeine, clozapine, fluvoxamine, olanzapine, tacrine, theophylline, clorazepate, lidocaine (oral), estradiol, flecanide, imipramine, heparin, insulin, mexiletine, opioids, propranolol, catecholamines, and cortisol. 

Clozapine should not be combined with any drugs that have the potential to suppress bone marrow function, such as carbamaz-epine. There have been isolated reports of respiratory arrest in patients taking both clozapine and a high-potency benzodiazepine. Thus, benzodiazepines (particularly in high doses) should not be administered to patients taking clozapine. 

Although clozapine has been considered an alternate agent, as mentioned earlier there is also a risk with this agent ( 494, 495 and 496). An unusual adverse effect of clozapine, apparently unrelated to NMS, is hyperthermia in 10% to 15% of patients (usually 0.5°C to 1°C, but virtually never above 40°C [104°F]). This symptom usually occurs between the fifth and the fifteenth days of treatment, after which, temperature returns to normal. Benzodiazepines (e.g., lorazepam) have also been recommended to either avoid or at least minimize the dose of antipsychotic. 

Sassim N, Grohmann R. Adverse drug reactions with clozapine and simultaneous application of benzodiazepines. Pharmacopsychiatry 1988 21 306-307. 

A large number of compounds in which thiophene was fused to other heterocyclic rings have been investigated, notably in the central nervous system agents. For example, the benzodiazepine derivative (365) is reported to be more active than Clozapine in conditioned avoidance response tests in the rat (80JMC878). The activity of such fused-ring thiophenes has been reviewed (81JHC1277). 

Benzodiazepines are used as hypnotics because they have the ability to increase total sleep time. They demonstrate minimal cardiovascular effects, but do have the ability to increase heart rate and decrease cardiac output. Most CNS depressants, including the benzodiazepines, exhibit the ability to relax skeletal muscles. Clozapine, a dibenzodiazepine, is used in the treatment of schizophrenia. It has both sedative and antipsychotic actions, and is the only FDA-approved medication indicated for treatment-resistant schizophrenia, and for reducing the risk of suicidal behavior in patients with schizophrenia. This drug can have potentially life-threatening side effects, but appears to have no abuse potential and will not be considered further. 

FIGURE 11-52. Positive symptom pharmacy. First-line treatment of positive symptoms is now atypical antipsychotics (SDA), not only for schizophrenia but also for positive symptoms associated with bipolar disorder, Alzheimer s disease, childhood psychoses, and other psychotic disorders. However, conventional antipsychotics (D2) and benzodiazepines (BZ) are still useful for acute intramuscular administration (in case of emergency), and D2 for monthly depot injections for noncompliant patients, as well as for second-line use after several atypical agents fail. Clozapine (C), polypharmacy, and combinations (combos) are relegated to second- and third-line treatment for positive symptoms of psychosis. 

FIGURE 11-56. Aggressive symptom pharmacy. Atypical antipsychotics (SDA), when sufficiently effective, are preferable (first line) to conventional antipsychotics (D2) for the management of aggression, hostility, and impulse control because of their more favorable side effect profiles. However, in an acute situation, intramuscular conventional antipsychotics or benzodiazepines (BZ) may be useful, and conventional antipsychotics or clozapine (C) may be required when atypical antipsychotics are not effective (second-line). 

Rothblat DS, Schneider JS (1997) Regionally specific effects of haloperidol and clozapine on dopamine reuptake in the striatum. Neurosci Lett 228 119-22 Roy-Byrne PP (2005) The GABA-benzodiazepine receptor complex structure, function, and role in anxiety. J Clin Psychiatry 66 Suppl 2 14-20... 

Cyt 3A3/4 metabolizes clozapine, sertindole, quetiapine common substrates -tricyclic antidepressants, nefazodone, sertraline, carbamazepine, ethosuximide, terfenadine, benzodiazepines, diltiazem, nifedipine, verapamil, erythromycin, cyclosporine, lidocaine, quinidine, cisapride, paracetamol. Common inhibitors -nefazodone, fluvoxamine, fluoxetine, ketoconazole. 

Phenothiazines and related drugs, e.g., chlorpromazine (Largactil/ Thorazine). Some tricyclic antidepressants, e.g., amitriptyline Dibenzodiazepine derivatives and thienobenzodiazepines, e.g., clozapine, olanzapine Benzodiazepines, e.g., diazepam (Valium), nitrezepam (Librium) and lorazepam Barbiturates Opiates... 

---