thiothixene

General

**BEERS Drug**

Pronunciation:
thye-oh-thix-een


Trade Name(s)

  • Navane Canadian Tradename

Ther. Class.
antipsychotics (conventional)

Pharm. Class.
thioxanthenes

Indications

Schizophrenia (considered second-line treatment after failure with atypical antipsychotics).

Action

Alters the effect of dopamine in the CNS.

Therapeutic Effect(s):

Diminished signs and symptoms of psychoses.

Pharmacokinetics

Absorption: Well absorbed following oral administration.

Distribution: Widely distributed; crosses the placenta.

Metabolism and Excretion: Mainly metabolized by the liver.

Half-life: 30 hr.

TIME/ACTION PROFILE (antipsychotic effects)

ROUTEONSETPEAKDURATION
POdays–wksunknownunknown

Contraindication/Precautions

Contraindicated in:

  • Hypersensitivity to thiothixene or other phenothiazines (cross-sensitivity may occur)
  • Circulatory collapse
  • Blood dyscrasias
  • Central nervous system depression;
  • Lactation: Lactation.

Use Cautiously in:

  • Diabetes mellitus
  • Respiratory disease
  • Prostatic hypertrophy
  • CNS tumors
  • Epilepsy
  • Intestinal obstruction
  • OB:  Neonates at ↑ risk for extrapyramidal symptoms and withdrawal after delivery when exposed during the 3rd trimester; use during pregnancy only if potential maternal benefit justifies potential fetal risk
  • Pedi:   Safety and effectiveness not established in children
  • Geri:  Initial dose ↓ may be required in older adults; ↑ risk of mortality in older adults treated for dementia-related psychosis.

Adverse Reactions/Side Effects

CV: hypotension, tachycardia, non-specific ECG changes

Derm: photosensitivity, pigment changes, rash

EENT: blurred vision, dry eyes, lens opacities

Endo: amenorrhea, breast enlargement, galactorrhea

GI: constipation, dry mouth, anorexia, ileus, nausea

GU: urinary retention

Hemat: AGRANULOCYTOSIS, leukocytosis, leukopenia, neutropenia

Metabolic: hyperpyrexia

Neuro: NEUROLEPTIC MALIGNANT SYNDROME, extrapyramidal reactions, sedation, tardive dyskinesia, seizures

Misc: allergic reactions

* CAPITALS indicate life-threatening.
Underline indicate most frequent.

Interactions

Drug-Drug

Drug-Natural Products:

Concomitant use of  kava-kava,  valerian,  skullcap,  chamomile, or  hops  can ↑ CNS depression.

Route/Dosage

PO (Adults): Mild conditions– 2 mg 3 times daily (up to 15 mg/day if necessary;  Severe conditions– 5 mg twice daily (up to 20–30 mg/day; not to exceed 60 mg/day).

Availability (generic available)

Capsules: 1 mg, 2 mg, 5 mg, 10 mg

Assessment

  • Monitor patient's mental status (orientation, mood, behavior) prior to and periodically during therapy.
  • Assess weight and BMI initially and throughout therapy.
  • Assess positive (hallucinations, delusions, agitation) and negative (social withdrawal) symptoms of schizophrenia.
  • Observe patient carefully when administering medication to ensure that medication is actually taken and not hoarded or cheeked.
  • Assess patient for level of sedation following administration.
  • Monitor patient for onset of akathisia (restlessness or desire to keep moving) and extrapyramidal side effects ( parkinsonian– difficulty speaking or swallowing, loss of balance control, pill rolling of hands, mask-like face, shuffling gait, rigidity, tremors; and  dystonic– muscle spasms, twisting motions, twitching, inability to move eyes, weakness of arms or legs) every 2 mo during therapy and 8–12 wk after therapy has been discontinued. Parkinsonian effects are more common in geriatric patients and dystonias are more common in younger patients. Notify health care professional if these symptoms occur, because reduction in dosage or discontinuation of medication may be necessary. Trihexyphenidyl, diphenhydramine, or benztropine may be used to control these symptoms. Benzodiazepines may alleviate akathisia.
  • Monitor for tardive dyskinesia (uncontrolled rhythmic movement of mouth, face, and extremities; lip smacking or puckering; puffing of cheeks; uncontrolled chewing; rapid or worm-like movements of tongue, excessive eye blinking). Notify health care professional immediately if these symptoms occur, as these side effects may be irreversible.
  • Monitor for development of neuroleptic malignant syndrome (fever, respiratory distress, tachycardia, convulsions, diaphoresis, hypertension or hypotension, pallor, tiredness, severe muscle stiffness, loss of bladder control). Notify health care professional immediately if these symptoms occur.
  • •Monitor for symptoms related to hyperprolactinemia (menstrual abnormalities, galactorrhea, sexual dysfunction).

Lab Test Considerations:

  • Thiothixene ↑ serum prolactin levels and ↓ serum uric acid levels. May cause false-positive or false-negative pregnancy tests.

    • Monitor CBC and differential prior to and periodically during therapy. Risk of leukopenia is highest between wk 4 and 10 of therapy.
    • Monitor liver function studies prior to and periodically during therapy. Risk of hepatotoxicity is greatest 2–4 wk after beginning therapy.
  • Obtain fasting blood glucose and cholesterol levels initially and during therapy.

Potential Diagnoses

Implementation

  • PO Administer capsules with food or milk to decrease gastric irritation.

Patient/Family Teaching

  • Instruct patient on need to take medication as directed. Take missed doses as soon as remembered unless 2 hr before next dose. Do not double doses. Patients on long-term high-dose therapy may need dose tapered to avoid withdrawal symptoms (dyskinesia, tremors, dizziness, nausea, and vomiting).
  • Drowsiness may occur. Caution patient to avoid driving or other activities requiring alertness until response to medication is known.
  • Inform patient of possibility of extrapyramidal symptoms and tardive dyskinesia. Caution patient to report these symptoms immediately to health care professional.
  • Instruct patient to use frequent mouth rinses, good oral hygiene, and sugarless gum or candy to minimize dry mouth. Consult health care professional if dry mouth continues for >2 wk.
  • Advise patient that increasing bulk and fluids in the diet and exercising may help minimize the constipating effects of this medication.
  • Caution patient to use sunscreen and protective clothing to prevent photosensitivity reactions.
  • Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and consult health care professional before taking any new medications.
  • Caution patient to avoid concurrent use of alcohol and other CNS depressants during therapy.
  • Caution patient to avoid exercising in hot weather and taking very hot baths, because this drug impairs temperature regulation.
  • Instruct patient to notify health care professional promptly if sore throat, fever, skin rashes or discoloration, weakness, tremors, visual disturbances, menstrual abnormalities, galactorrhea or sexual dysfunction are noted.
  • Advise patient to notify health care professional of medication regimen prior to treatment or surgery.
  • Rep:  Advise patient to use effective contraception during therapy and to notify health care professional immediately if pregnancy is suspected or if breastfeeding. May cause neonatal extrapyramidal and/or withdrawal symptoms (agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress, feeding disorder) following delivery if taken during third trimester.
  • Emphasize the importance of continued medical follow-up for psychotherapy, eye exams, and laboratory tests, and to monitor response to medication and detect side effects.

Evaluation/Desired Outcomes

  • Decrease in positive symptoms (hallucinations, delusions, agitation) of schizophrenia.
  • Decrease in excited, manic behavior.

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