Drug information of Thioridazine
Mechanism of effect
Precise mechanism(s) of antipsychotic action not determined, but may be principally related to antidopaminergic effects.The basic pharmacological activity of Thioridazine is similar to that of other phenothiazines, but is associated with minimal extrapyramidal stimulation.
Thioridazine is a piperidine phenothiazine which blocks postsynaptic mesolimbic dopaminergic receptors in the brain; also has activity at serotonin, noradrenaline, and histamine receptors.
Absorption is Rapid .Hepatic metabolism by sulphoxidation (primarily), demethylation (2%), and hydroxylation (limited); active metabolites mesoridazine and sulphoridazine. Half-Life Elimination is5 to 27 hours and Protein Binding is96% to 99.3%
Usual Adult Dose for Schizophrenia
Initial dose: 50 to 100 mg orally 3 times a day
Maintenance dose: 200 to 800 mg/day, divided into 2 to 4 doses
Maximum dose: 800 mg/day
Usual Pediatric Dose for Schizophrenia
Initial dose: 0.5 mg/kg/day orally, in divided doses
Maximum dose: 3 mg/kg/day, in divided doses
-The dose should be increased gradually until therapeutic effects are observed and/or the maximum dose is reached.
Drug contraindicationssevere hypersensitivity reactions
Side effectsnausea , Headache , dry mouth , constipation , Seizures , Blurred vision , vertigo , Diarrhea , urticaria , Peripheral edema , psychotic symptoms , Gynecomastia , Weight increase , Agranulocytosis , nasal stuffiness , difficulty urinating , skin rush , Leukopenia
InteractionsAcetylcholine , Paroxetine , Propranolol , Tetrabenazine , Tretinoin , Anti Histamine , Sertraline , Citalopram , escitalopram , Pindolol , Sevoflurane , Fluvoxamine , Fluoxetine , Chlorpheniramine , fentanyl , Ranolazine , potassium citrate , Sodium Oxybate , Toremifene , Mirabegron , Tapentadol , safinamide , Histrelin , ISOPROTERENOL , ritonavir , Apomorphine , Dolasetron , Palonosetron , vandetanib , Droperidol , Quinine , Chloroquine , sparfloxacin , Procainamide , Mefloquine , Indapamide , Dofetilide , Inotuzumab , Promazine , Abiraterone , Peginterferon alfa-2b , Vasopressin , Arsenic trioxide , Celecoxib , Tipranavir , Halofantrine , Grepafloxacin , Darifenacin , Mibefradil , Dexfenfluramine , Trimeprazine , aminolevulinic acid oral , Aminolevulinic acid topical , cobicistat , Delavirdine , Terfenadine , Abarelix , Asenapine , Alfuzosin , Amisulpride , Acetaminophen and benzhydrocodone , Perflutren , Pimavanserin , lenvatinib , Apalutamide , Crizotinib , Entrectinib , Oxymorphone , Dacomitinib , gilteritinib , glycopyrrolate topical , Gadofosveset , glasdegib , Eliglustat , Naltrexone and Bupropion , Bepridil , bedaquiline , Gefitinib , Dasatinib , Gemtuzumab , vemurafenib , rolapitant , Vernakalant , Asunaprevir
Thioridazine has been shown to prolong the QTc interval in a dose related manner, and drugs with this potential, including Thioridazine , have been associated with Torsades de pointes type arrhythmias and sudden death. Due to its potential for significant, possibly life threatening, proarrhythmic effects, Thioridazine should be reserved for use in the treatment of schizophrenic patients who fail to show an acceptable response to adequate courses of treatment with other antipsychotic drugs, either because of insufficient effectiveness or the inability to achieve an effective dose due to intolerable adverse effects from those drugs .
Tardive dyskinesia, a syndrome consisting of potentially irreversible, involuntary, dyskinetic movements may develop in patients treated with antipsychotic drugs. Although the prevalence of the syndrome appears to be highest among the elderly, especially elderly women, it is impossible to rely upon prevalence estimates to predict, at the inception of antipsychotic treatment, which patients are likely to develop the syndrome. Whether antipsychotic drug products differ in their potential to cause tardive dyskinesia is unknown.
Thioridazine may cause somnolence, postural hypotension, motor and sensory instability, which may lead to falls and, consequently, fractures or other injuries. For patients with diseases, conditions, or medications that could exacerbate these effects, complete fall risk assessments when initiating antipsychotic treatment and recurrently for patients on long-term antipsychotic therapy.
Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. Thioridazine is not approved for the treatment of patients with dementia-related psychosis .
A potentially fatal symptom complex, sometimes referred to as Neuroleptic Malignant Syndrome (NMS), has been reported in association with antipsychotic drugs. Clinical manifestations of NMS are hyperpyrexia, muscle rigidity, altered mental status and evidence of autonomic instability (irregular pulse or blood pressure, tachycardia, diaphoresis, and cardiac dysrhythmias).
The management of NMS should include :
1) immediate discontinuation of antipsychotic drugs and other drugs not essential to concurrent therapy,
2) intensive symptomatic treatment and medical monitoring, and
3) treatment of any concomitant serious medical problems for which specific treatments are available.
There is no general agreement about specific pharmacological treatment regimens for uncomplicated NMS.
As in the case of other phenothiazines, Thioridazine is capable of potentiating central nervous system depressants (e.g., alcohol, anesthetics, barbiturates, narcotics, opiates, other psychoactive drugs, etc.) as well as atropine and phosphorus insecticides. Severe respiratory depression and respiratory arrest have been reported when a patient was given a phenothiazine and a concomitant high dose of a barbiturate.
Leukopenia and/or agranulocytosis and convulsive seizures have been reported but are infrequent. In schizophrenic patients with epilepsy, anticonvulsant medication should be maintained during treatment with Thioridazine .
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 the recommended limits of dosage.
Points of recommendation
To make sure this medicine is safe for you, tell your doctor if you have:
• If you have an allergy to thioridazine or any other part of that.
• If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
• If you have heart problems.
• If you have had in the past a heartbeat that does not feel normal.
• If you are very sleepy.
• If you have recently drunk a lot of alcohol or taken a big amount of drugs that may slow your actions like phenobarbital or some pain drugs like oxycodone.
• If you are taking any of these drugs: Fluoxetine, fluvoxamine, paroxetine, pindolol, or propranolol.
Avoid driving and doing other tasks or actions that call for you to be alert until you see how thioridazine affects you.
A very bad and sometimes deadly health problem called neuroleptic malignant syndrome (NMS) may happen. Call your doctor right away if you have any fever, muscle cramps or stiffness, dizziness, very bad headache, confusion, change in thinking, fast heartbeat, heartbeat that does not feel normal, or are sweating a lot.
Low white blood cell counts have happened with drugs like this one. This may lead to a higher chance of getting an infection. Deadly infections have rarely happened. Tell your doctor if you have ever had a low white blood cell count. Call your doctor right away if you have signs of infection like fever, chills, or sore throat. Talk with your doctor.
If you are 65 or older, use this medicine with care. You could have more side effects.
This medicine may cause the results of some pregnancy tests to be wrong. Talk with the doctor.
Take with or without food. Take with food if it causes an upset stomach .Take a missed dose as soon as you think about it. If it is close to the time for your next dose, skip the missed dose and go back to your normal time. Do not take 2 doses at the same time or extra doses.