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Drug Interactions between paliperidone and thioridazine

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Major

thioridazine paliperidone

Applies to: thioridazine and paliperidone

CONTRAINDICATED: Thioridazine can cause dose-related prolongation of the QT interval. Theoretically, coadministration with other agents that can prolong the QT interval may result in additive effects and increased risk of ventricular arrhythmias including torsade de pointes and sudden death. Thioridazine treatment alone has been associated with several reported cases of torsade de pointes and sudden death. In general, the risk of an individual agent or a combination of agents causing ventricular arrhythmia in association with QT prolongation is largely unpredictable but may be increased by certain underlying risk factors such as congenital long QT syndrome, cardiac disease, and electrolyte disturbances (e.g., hypokalemia, hypomagnesemia). The extent of drug-induced QT prolongation is dependent on the particular drug(s) involved and dosage(s) of the drug(s). In addition, certain agents with anticholinergic properties (e.g., sedating antihistamines; antispasmodics; neuroleptics; phenothiazines; skeletal muscle relaxants; tricyclic antidepressants; disopyramide) may have additive parasympatholytic and central nervous system-depressant effects when used in combination with thioridazine. Excessive parasympatholytic effects may include paralytic ileus, hyperthermia, mydriasis, blurred vision, tachycardia, urinary retention, psychosis, and seizures.

MANAGEMENT: Coadministration of thioridazine with other drugs that can prolong the QT interval is considered contraindicated.

References (9)
  1. Fletcher GF, Kazamias TM (1969) "Cardiotoxic effects of Mellaril: conduction disturbances and supraventricular arrhythmias." Am Heart J, 78, p. 135-8
  2. Liberatore MA, Robinson DS (1984) "Torsade de pointes: a mechanism for sudden death associated with neuroleptic drug therapy?" J Clin Psychopharmacol, 4, p. 143-6
  3. (2001) "Product Information. Mellaril (thioridazine)." Sandoz Pharmaceuticals Corporation
  4. Hartigan-Go K, Bateman DN, Nyberg G, Martensson E, Thomas SHL (1996) "Concentration-related pharmacodynamic effects of thioridazine and its metabolites in humans." Clin Pharmacol Ther, 60, p. 543-53
  5. Glassman AH, Bigger JT Jr (2001) "Antipsychotic drugs: prolonged QTc interval, torsade de pointes, and sudden death." Am J Psychiatry, 158, p. 1774-82
  6. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  7. Canadian Pharmacists Association (2006) e-CPS. http://www.pharmacists.ca/function/Subscriptions/ecps.cfm?link=eCPS_quikLink
  8. Cerner Multum, Inc. "Australian Product Information."
  9. EMA. European Medicines Agency. European Union (2013) EMA - List of medicines under additional monitoring. http://www.ema.europa.eu/ema/index.jsp?curl=pages/regulation/document_listing/document_listing_000366.jsp&mid=WC0b01ac058067c852

Drug and food interactions

Moderate

paliperidone food

Applies to: paliperidone

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of paliperidone. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

Administration with food may increase the bioavailability of paliperidone from the extended release tablets. In healthy ambulatory subjects, administration of a 12 mg paliperidone extended release tablet with a standard high-fat/high-caloric meal resulted in 60% and 54% increases, respectively, in the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of paliperidone compared to administration under fasting conditions. The clinical significance of these changes is unknown.

MANAGEMENT: Patients receiving paliperidone should be advised to avoid the consumption of alcohol. Since clinical trials establishing the safety and efficacy of paliperidone were carried out without regard to the timing of meals, presumably paliperidone may be administered with or without food.

References (1)
  1. (2007) "Product Information. Invega (paliperidone)." Janssen Pharmaceuticals
Moderate

thioridazine food

Applies to: thioridazine

GENERALLY AVOID: Concurrent use of ethanol and phenothiazines may result in additive CNS depression and psychomotor impairment. Also, ethanol may precipitate dystonic reactions in patients who are taking phenothiazines. The two drugs probably act on different sites in the brain, although the exact mechanism of the interaction is not known.

MANAGEMENT: Patients should be advised to avoid alcohol during phenothiazine therapy.

References (2)
  1. Lutz EG (1976) "Neuroleptic-induced akathisia and dystonia triggered by alcohol." JAMA, 236, p. 2422-3
  2. Freed E (1981) "Alcohol-triggered-neuroleptic-induced tremor, rigidity and dystonia." Med J Aust, 2, p. 44-5

Therapeutic duplication warnings

Therapeutic duplication is the use of more than one medicine from the same drug category or therapeutic class to treat the same condition. This can be intentional in cases where drugs with similar actions are used together for demonstrated therapeutic benefit. It can also be unintentional in cases where a patient has been treated by more than one doctor, or had prescriptions filled at more than one pharmacy, and can have potentially adverse consequences.

Duplication

Antipsychotics

Therapeutic duplication

The recommended maximum number of medicines in the 'antipsychotics' category to be taken concurrently is usually one. Your list includes two medicines belonging to the 'antipsychotics' category:

  • paliperidone
  • thioridazine

Note: In certain circumstances, the benefits of taking this combination of drugs may outweigh any risks. Always consult your healthcare provider before making changes to your medications or dosage.


Report options

Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.