Phenothiazines overdose

Any suspected overdose patient should be transported to a health care facility as soon as possible. Any patient with clinical signs of phenothiazine overdose should be admitted. 

Therapy for phenothiazines is generally supportive and similar to that for tricyclic antidepressant overdose. Physostigmine can reverse the central and peripheral anticholinergic manifestations of phenothiazines however, because these manifestations are rarely life-threatening and because physostigmine may cause severe bradycardia or asystole it is not recommended for treatment of pheno-thiazine overdose. Because of the large volume of distribution and extensive protein binding, hemodialysis or hemoperfusion is not beneficial for phenothiazine overdose. 

Low antiepileptic drug levels, drug overdose (e.g., cocaine, isoniazid, theophylline, phenothiazine), ethanol-related, and drug withdrawal... 

A number of drugs in addition to atropine and scopolamine have antimuscarinic properties. Tbese include tricyclic antidepressants, phenothiazines, and antihistamines. Physostigmine has been used in the treatment of acute toxicity produced by these compounds. However, physostigmine can produce cardiac arrhythmias and other serious toxic effects of its own, and therefore, it should be considered as an antidote only in life-threatening cases of anticholinergic drug overdose. 

Other nervous system depressants that could trigger a GHB overdose reaction are benzodiazepines (mild tranquilizers such as Valium and Xanax), phenothiazines (potent tranquilizers like Thorazine and Stellazine), various painkillers (barbiturates and opiates), anticonvulsants (Dilantin and phenobarbital), and even many over-the-counter allergy and sleep remedies. 

Toxicity. Serious medication-related adverse effects associated with actual or potential damage to tissues, organs, or the entire body system. Toxicity may be directly related to critically elevated blood levels of a drug and may be acute (as in tricyclic antidepressant overdose) or chronic (as in prolonged, moderately elevated lithium level). A drug may also produce "toxic effects" at therapeutic doses (such as phenothiazine s potential for inducing bone marrow damage, which in turn causes decreased production of white blood cells). 

Overdose of M blockers Poisoning most commonly follows excessive ingestion of over-the-counter (OTC) antihistamines and cold medications, or attempts to induce hallucinations. Note that M-blocking side effects (and possible toxicity) occur with both tricyclic antidepressants and phenothiazines. Management is largely symptomatic, although physostigmine can be seful and may counter both peripheral and central effects. 

B. Toxicodynamics Toxicodynamics is a term used to denote the injurious effects of toxins, ie, their pharmacodynamics. A knowledge of toxicodynamics can be useful in the diagnosis and management of poisoning. For example, hypertension and tachycardia are typically seen in overdoses with amphetamines, cocaine, and antimuscarinic drugs. Hypotension with bradycardia occurs with overdoses of calcium channel blockers, beta-blockers, and sedative-hypnotics. Hypotension with tachycardia occurs with tricyclic antidepressants, phenothiazines, and theophylline. Hyperthermia is most frequently a result of overdose of drugs with antimuscarinic actions, the salicylates, or sympathomimetics. Hypothermia is more likely to occur with toxic doses of ethanol and other CNS depressants. Increased respiratory rate is often a feature of... 

Phenothiazine antipsychotic drug prototype blocks most dopamine receptors in the CNS. Tox atropine-like, EPS dysfunction, hyperprolactinemia, postural hypotension, sedation, seizures (in overdose), additive effects with other CNS depressants. 

The concurrent use of MAOIs and phenothiazines is usually safe and effective. However, rarely, cases of possible neuroleptic malignant syndrome or hyperpyrexia have been reported with MAOIs and chlorpromazine, levomepromazine or trifluoperazine. Some of these cases were fatal Chiorpromazine has been successfully used for treatment of the serotonin syndrome occurring with MAOIs and other drugs. Moclobemide has been used with various phenothiazines without problem, but one case of fatal overdose is attributed to an interaction between moclobemide and perazine. 

Clinically relevant interactions were not noted when moclobemide was given with one or more neuroleptics (including phenothiazines such as chlorpromazine, levomepromazine, thioridazine). Adverse effects such as hypotension, tachycardia, drowsiness, tremor, and constipation were somewhat more Sequent, probably due to additive effects. A fatal case of overdose with moclobemide and perazine was attributed to syn-ergisSc effects resulSng in funcSonal cardiovascular disorder. ... 

A. G. Gallanosa, D. A. Spyker, J. R. Shipe and D. L. Morris, Human xylazine overdose a comparative review with clonidine, phenothiazines, and tricyclic antidepressants, J. Toxicol. Clin. Toxicol., 1981,18, 663-678. 

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