Thioridazine

DEA Class;  Rx

Common Brand Names; Mellaril

Documented hypersensitivity to phenothiazines

Coadministration with cytochrome P450 2D6 isozyme inhibitors (eg, fluoxetine and paroxetine) and certain other drugs (eg, fluvoxamine, propranolol, and pindolol)

Patients who are known to have a genetic defect leading to reduced levels of activity of P450 2D6

Patients with hypertensive or hypotensive heart disease of extreme degree

Patients in comatose state

Severe CNS depression

Severe hyper-/hypotensive heart disease

• EPS (muscle stiffness, dystonia, parkinsonism, tardive dyskinesia, akathisia) (60%)
• NMS (infrequent but serious)
• Sedation
• Anticholinergic effects
• Weight gain
• Oligomenorrhea/amenorrhea
• Erectile dysfunction
• Insomnia
• Restlessness
• Anxiety
• Euphoria
• Agitation
• Depression
• Weakness
• Headache
• Cerebral edema
• Poikilothermia
• Orthostatic hypotension
• Tachycardia
• Dizziness
• Lens opacities (prolonged use)
• Anorexia
• Dyspepsia
• Constipation
• Ileus
• Blood dyscrasia
• ECG changes
• Photosensitivity
• Pruritis
• Diarrhea
• Galactorrhea
• Ejaculatory disorder
• Seizure (rare)
• Priapism (rare)
• Cholestatic jaundice (rare)

Avoid using in children with suspected Reye’s syndrome

Hypotension may be particularly severe in patients with pheochromocytoma or mitral insufficiency

Depresses hypothalamic thermoregulatory mechanism; exposure to extreme temperatures may cause hypo- or hyperthermia

Leukopenia and/or agranulocytosis and convulsive seizures reported but infrequent; in schizophrenic patients with epilepsy, anticonvulsant medication should be maintained during treatment

Pigmentary retinopathy, which has been observed primarily in patients taking larger than recommended doses, is characterized by diminution of visual acuity, brownish coloring of vision, and impairment of night vision; examination of the fundus discloses deposits of pigment; the possibility of this complication may be reduced by remaining within recommended limits of dosage

Where patients are participating in activities requiring complete mental alertness (eg, driving) it is advisable to administer the phenothiazines cautiously and to increase the dosage gradually

Female patients appear to have a greater tendency to orthostatic hypotension than male patients; administration of epinephrine should be avoided in treatment of drug-induced hypotension as it may induce a reversed epinephrine effect on occasion; should a vasoconstrictor be required, the most suitable are levarterenol and phenylephrine

An increase in mammary neoplasms has been found in rodents after chronic administration of neuroleptic drugs; neither clinical studies nor epidemiologic studies conducted to date have shown an association between chronic administration of these drugs and mammary tumorigenesis; the available evidence is considered too limited to be conclusive at this time

Use during pregnancy only if potential benefit justifies potential risk to fetus

Neonates exposed to antipsychotic drugs, during third trimester of pregnancy are at risk for extrapyramidal and/or withdrawal symptoms following delivery; there have been reports of agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress and feeding disorder; these complications have varied in severity; while in some cases symptoms have been self-limited, in other cases neonates have required intensive care unit support and prolonged hospitalization

Not known whether the drug is present in the milk; infants exposed to antipsychotic agents should be monitored for signs of adverse effects; routine monitoring of infant serum concentrations not recommended