Drug

Thioridazine

Common brand names:

Mellaril

Thioridazine is used to treat symptoms associated with psychosis; depression with worry and restlessness in adults; irritability, worry, and fear in elderly; and severe behavioral problems in children, including fighting and hyperactivity. It is classified as a phenothiazine neuroleptic.

Summary of Interactions with Vitamins, Herbs, & Foods

  • Negative Interactions

    2
    • Thioridazine

      Bacopa

      Potential Negative Interaction

      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.

      Bacopa
      Thioridazine
      ×
      1. Ganguly DK, Malhotra CL. Some behavioral effects of an active fraction from Herpestis monniera Linn. (Brahmi). Indian J Med Res 1967;55:473-82.
    • Thioridazine

      Vitamin A

      Potential Negative Interaction

      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 A
      Thioridazine
      ×
      1. Curtis JL. Effects of medication on plasma vitamin A concentrations. Clin Chem 1976;22:695.
  • Supportive Interactions

    3
    • Thioridazine

      Vitamin B3 (Niacin)

      Support Medicine

      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
      ×
      1. 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.
    • Thioridazine

      Coenzyme Q10

      Reduce Side Effects

      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 Q10
      Thioridazine
      ×
      1. 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.
    • Thioridazine

      Potassium

      Reduce Side Effects

      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.

      Potassium
      Thioridazine
      ×
      1. Sydney MA. Ventricular arrhythmias associated with use of thioridazine hydrochloride in alcohol withdrawal. Br Med J 1973;4:467.
  • Explanation Required

    1
    • Thioridazine

      Vitamin C

      Needs Explanation

      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 C
      Thioridazine
      ×
      1. Kanofsky JD, Kay SR, Lindenmayer JP, Seifter E. Ascorbic acid action in neuroleptic-associated amenorrhea. J Clin Psychopharmacol 1989;9:388-9 [letter].
      2. 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].
The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a new supplement with your doctor or pharmacist.

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