Drug
Thioridazine
Pronounced
"thigh-oh-RID-uh-zeen"
Drug Interactions
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
Some products that may interact with this drug include: cabergoline, lithium.
Many drugs besides thioridazine may affect the heart rhythm (QT prolongation), including amiodarone, dofetilide, pimozide, procainamide, quinidine, sotalol, macrolide antibiotics (such as erythromycin), ziprasidone, among others.
Other medications can affect the removal of thioridazine from your body, which may affect how thioridazine works. Examples include bupropion, cinacalcet, dacomitinib, duloxetine, mirabegron, pindolol, propranolol, rolapitant, terbinafine, certain SSRI antidepressants (such as fluoxetine, fluvoxamine, paroxetine), among others.
Thioridazine can speed up the removal of other drugs from your body, which may affect how they work. Examples of affected drugs include elacestrant, lonafarnib, mavacamten, among others.
This medication may decrease the effectiveness of hormonal birth control such as pills, patch, or ring. This could cause pregnancy. Discuss with your doctor or pharmacist if you should use reliable backup birth control methods while using this medication. Also tell your doctor if you have any new spotting or breakthrough bleeding, because these may be signs that your birth control is not working well.
Tell your doctor or pharmacist if you are taking other products that cause drowsiness such as opioid pain or cough relievers (such as codeine, hydrocodone), alcohol, marijuana (cannabis), drugs for sleep or anxiety (such as alprazolam, lorazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), or antihistamines (such as cetirizine, diphenhydramine).
Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.
Negative Interactions
2- Potential Negative Interaction
Thioridazine
Bacopa
An animal study found that the effects of chlorpromazine, a drug similar to (perphenazine, prochlorperazine, thioridazine), were enhanced when a bacopa extract was given along with it. Until more is known, people taking medications from this family of drugs (called phenothiazines) should not take bacopa.
BacopaThioridazine- Ganguly DK, Malhotra CL. Some behavioral effects of an active fraction from Herpestis monniera Linn. (Brahmi). Indian J Med Res 1967;55:473-82.
- Potential Negative Interaction
Thioridazine
Vitamin A
A review of people taking thioridazine showed that they had higher blood levels of vitamin A than did individuals not using the drug. More research is necessary to determine whether taking vitamin A supplements with thioridazine might cause dangerously high vitamin A levels. Until more is known, people taking thioridazine should exercise caution with vitamin A supplementation and be alert for side effects such as bone pain, headaches, dry scaly skin, and hair loss.
Vitamin AThioridazine- Curtis JL. Effects of medication on plasma vitamin A concentrations. Clin Chem 1976;22:695.
Supportive Interactions
3- Support Medicine
Thioridazine
Vitamin B3 (Niacin)
In a controlled study, individuals taking thioridazine for psychosis cooperated better and withdrew less from other people when niacin (nicotinic acid), 300–1,500 mg each day, was added. Whether people who are taking thioridazine for other mental health problems might benefit from niacin supplementation is unknown.
Vitamin B3 (Niacin)Thioridazine- Lehmann HE, Ban TA, Saxena BM. Nicotinic acid, thioridazine, fluoxymesterone and their combinations in hospitalized geriatric patients. Can Psychiatr Assoc J 1972;17:315-20.
- Reduce Side Effects
Thioridazine
Coenzyme Q10
This interaction is based on this drug belonging to a drug class. While this drug may differ from the text and references below, drugs within this class work in a similar way and this interaction is applicable to drugs within the same class.
Phenothiazine drugs like thioridazine can cause changes in heart activity in some people, which might be prevented with coenzyme Q10 supplementation. Therefore, some doctors and pharmacists may recommend coenzyme Q10 supplements to individuals taking thioridazine.
Coenzyme Q10Thioridazine- Kishi T, Makino K, Okamoto T, et al. In Yamamura Y, Folkers K, Ito Y, eds. Biochemical and Clinical Aspects of Coenzyme Q, Volume 2. Amsterdam: Elsevier/North Holland Biomedical Press, 1980, 139-57.
- Reduce Side Effects
Thioridazine
Potassium
Some people taking thioridazine experience changes in the electrical activity of the heart, which sometimes improve with potassium supplementation. More research is needed to determine if people taking thioridazine might prevent heart problems by supplementing with potassium.
PotassiumThioridazine- Sydney MA. Ventricular arrhythmias associated with use of thioridazine hydrochloride in alcohol withdrawal. Br Med J 1973;4:467.
Explanation Required
1- Needs Explanation
Thioridazine
Vitamin C
Taking phenothiazine drugs can stop menstruation in some women. A 45-year-old woman taking thioridazine started menstruating once she began supplementing with 6 grams of vitamin C daily. Controlled studies are needed to determine whether women taking thioridazine, who are experiencing menstrual changes, might benefit from supplemental vitamin C. Vitamin C might also enhance the effectiveness of neuroleptic drugs, such as thioridazine, in the treatment of schizophrenia. One uncontrolled study showed that 10 of 13 individuals experienced a reduction in disorganized thoughts, hallucinations, and suspicious thoughts when 8 grams of vitamin C was added to their daily drug therapy. Controlled studies are needed to determine whether people taking thioridazine for schizophrenia might benefit from vitamin C supplementation.
Vitamin CThioridazine- Kanofsky JD, Kay SR, Lindenmayer JP, Seifter E. Ascorbic acid action in neuroleptic-associated amenorrhea. J Clin Psychopharmacol 1989;9:388-9 [letter].
- Beauclair L, Vinogradov S, Riney SJ, et al. An adjunctive role for ascorbic acid in the treatment of schizophrenia? J Clin Psychopharmacol 1987;7:282-3 [letter].