Tapazole


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Related to Tapazole: hyperthyroidism

Tapazole

 [tap´ah-zōl]
trademark for a preparation of methimazole, used as a thyroid inhibitor.

methimazole

Apo-Methimazole (CA), Tapazole

Pharmacologic class: Thiomidazole derivative

Therapeutic class: Antithyroid drug

Pregnancy risk category D

Action

Directly interferes with thyroid synthesis by preventing iodine from combining with thyroglobulin, leading to decreased thyroid hormone levels

Availability

Tablets: 5 mg, 10 mg

Indications and dosages

Mild hyperthyroidism

Adults and adolescents: Initially, 15 mg P.O. daily in three equally divided doses at approximately 8-hour intervals. For maintenance, 5 to 15 mg/day in equally divided doses at approximately 8-hour intervals.

Children: Initially, 0.4 mg/kg/day in three divided doses at 8-hour intervals. For maintenance, approximately 0.2 mg/kg/day in three divided doses at 8-hour intervals.

Moderate hyperthyroidism

Adults and adolescents: Initially, 30 to 40 mg P.O. daily in three equally divided doses at approximately 8-hour intervals. For maintenance, 5 to 15 mg/day in three equally divided doses at approximately 8-hour intervals.

Children: 0.4 mg/kg/day P.O. as a single dose or in divided doses at 8-hour intervals. For maintenance, approximately 0.2 mg/kg/day as a single dose or in three divided doses at 8-hour intervals.

Severe hyperthyroidism

Adults and adolescents: Initially, 60 mg/day P.O. in three equally divided doses at approximately 8-hour intervals. For maintenance, 5 to 15 mg/day in three equally divided doses at approximately 8-hour intervals.

Children: Initially, 0.4 mg/kg/day P.O. as a single dose or in three divided doses at 8-hour intervals. For maintenance, approximately 0.2 mg/kg/day as a single dose or in three divided doses at 8-hour intervals.

Contraindications

• Hypersensitivity to drug
• Breastfeeding

Precautions

Use cautiously in:
• bone marrow depression
• patients older than age 40
• pregnant patients.

Administration

• Give with meals as needed to reduce GI upset.

Adverse reactions

CNS: headache, vertigo, paresthesia, neuritis, depression, neuropathy, CNS stimulation

GI: nausea, vomiting, constipation, epigastric distress, ileus, salivary gland enlargement, dry mouth, anorexia

GU: nephritis

Hematologic: thrombocytopenia, agranulocytosis, leukopenia, aplastic anemia

Hepatic: jaundice, hepatic dysfunction, hepatitis

Metabolic: hypothyroidism

Musculoskeletal: joint pain, myalgia

Skin: rash, urticaria, skin discoloration, pruritus, erythema nodosum, exfoliative dermatitis, abnormal hair loss

Other: fever, lymphadenopathy, lupuslike syndrome

Interactions

Drug-drug.Aminophylline, oxtriphylline, theophylline: decreased clearance of both drugs

Amiodarone, iodine, potassium iodide: decreased response to methimazole

Anticoagulants: altered requirements for both drugs

Beta-adrenergic blockers: altered beta blocker clearance

Digoxin: increased digoxin blood level

Drug-diagnostic tests.Granulocytes, hemoglobin, platelets, white blood cells: decreased values

Patient monitoring

• Check for agranulocytosis in patients older than age 40 and in those receiving more than 40 mg/day.
• Assess hematologic studies. Agranulocytosis usually occurs within first 2 months of therapy and is rare after 4 months.
• Monitor thyroid function tests periodically. Once hyperthyroidism is controlled, elevated thyroid-stimulating factor indicates need for dosage decrease.
• Assess liver function tests and check for signs and symptoms of hepatic dysfunction.
• Monitor patient for fever, sore throat, and other evidence of infection as well as for unusual bleeding or bruising.
• Assess patient for signs and symptoms of hypothyroidism, such as hard edema of subcutaneous tissue, drowsiness, slow mentation, dryness or loss of hair, decreased temperature, hoarseness, and muscle weakness.

Patient teaching

• Tell patient to take with meals if GI upset occurs.
• Advise patient to take exactly as prescribed to maintain constant blood level.
• Tell patient to report rash, fever, sore throat, unusual bleeding or bruising, headache, rash, yellowing of skin or eyes, abdominal pain, vomiting, or flulike symptoms.
• Caution female patient not to breastfeed while taking drug.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.

methimazole

(meth-im-a-zole) ,

Tapazole

(trade name)

Classification

Therapeutic: antithyroid agents
Pregnancy Category: D

Indications

Palliative treatment of hyperthyroidism.Used as an adjunct to control hyperthyroidism in preparation for thyroidectomy or radioactive iodine therapy.

Action

Inhibits the synthesis of thyroid hormones.

Therapeutic effects

Decreased signs and symptoms of hyperthyroidism.

Pharmacokinetics

Absorption: Rapidly absorbed following oral administration.
Distribution: Crosses the placenta and enters breast milk in high concentrations.
Metabolism and Excretion: Mostly metabolized by the liver; <10% eliminated unchanged by the kidneys.
Half-life: 3–5 hr.

Time/action profile (effect on thyroid function)

ROUTEONSETPEAKDURATION
PO1 wk4–10 wkwk

Contraindications/Precautions

Contraindicated in: Hypersensitivity; Lactation: Lactation.
Use Cautiously in: Patients with ↓ bone marrow reserve;Patients >40 yr (↑ risk of agranulocytosis); Obstetric: May be used cautiously; however, thyroid problems may occur in the fetus.

Adverse Reactions/Side Effects

Central nervous system

  • drowsiness
  • headache
  • vertigo

Gastrointestinal

  • diarrhea
  • hepatotoxicity
  • loss of taste
  • nausea
  • parotitis
  • vomiting

Dermatologic

  • rash (most frequent)
  • skin discoloration
  • urticaria

Hematologic

  • agranulocytosis (life-threatening)
  • anemia
  • leukopenia
  • thrombocytopenia

Musculoskeletal

  • arthralgia

Miscellaneous

  • fever
  • lymphadenopathy

Interactions

Drug-Drug interaction

Additive bone marrow depression with antineoplastics or radiation therapy.Antithyroid effect may be ↓ by potassium iodide or amiodarone.↑ risk of agranulocytosis with phenothiazines.May alter response to warfarin and digoxin.

Route/Dosage

Oral (Adults) Thyrotoxic crisis—15–20 mg q 4 hr during the first 24 hr (with other interventions). Hyperthyroidism—15–60 mg/day as a single dose or divided doses for 6–8 wk. Maintenance—5–30 mg/kg as a single dose or 2 divided doses.
Oral (Children) Initial—400 mcg (0.4 mg)/kg/day in single dose or 2 divided doses. Maintenance—200 mcg/kg/day in single dose or 2 divided doses.

Availability (generic available)

Tablets: 5 mg, 10 mg

Nursing implications

Nursing assessment

  • Monitor response for symptoms of hyperthyroidism or thyrotoxicosis (tachycardia, palpitations, nervousness, insomnia, fever, diaphoresis, heat intolerance, tremors, weight loss, diarrhea).
  • Assess for development of hypothyroidism (intolerance to cold, constipation, dry skin, headache, listlessness, tiredness, or weakness). Dose adjustment may be required.
  • Assess for skin rash or swelling of cervical lymph nodes. Treatment may be discontinued if this occurs.
  • Lab Test Considerations: Monitor thyroid function studies prior to therapy, monthly during initial therapy, and every 2–3 mo during therapy.
    • Monitor WBC and differential counts periodically during therapy. Agranulocytosis may develop rapidly; usually occurs during the first 2 mo and is more common in patients over 40 yr and those receiving >40 mg/day. This necessitates discontinuation of therapy.
    • May cause ↑ AST, ALT, LDH, alkaline phosphatase, serum bilirubin, and prothrombin time.

Potential Nursing Diagnoses

Noncompliance (Patient/Family Teaching)

Implementation

  • Do not confuse methimazole with metolazone.
  • Oral: Administer at same time in relation to meals every day. Food may either increase or decrease absorption.

Patient/Family Teaching

  • Instruct patient to take medication as directed, around the clock. Take missed doses as soon as remembered; take both doses together if almost time for next dose; check with health care professional if more than 1 dose is missed. Consult health care professional prior to discontinuing medication.
  • Instruct patient to monitor weight 2–3 times weekly. Notify health care professional of significant changes.
  • May cause drowsiness. Caution patient to avoid driving or other activities requiring alertness until response to medication is known.
  • Advise patient to consult health care professional regarding dietary sources of iodine (iodized salt, shellfish).
  • Advise patient to report sore throat, fever, chills, headache, malaise, weakness, yellowing of eyes or skin, unusual bleeding or bruising, rash, or symptoms of hyperthyroidism or hypothyroidism promptly.
  • Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
  • Advise patient to carry identification describing medication regimen at all times.
  • Advise patient to notify health care professional of medication regimen prior to treatment or surgery.
  • Emphasize the importance of routine exams to monitor progress and to check for side effects.

Evaluation/Desired Outcomes

  • Decrease in severity of symptoms of hyperthyroidism (lowered pulse rate and weight gain).
  • Return of thyroid function studies to normal.
  • May be used as short-term adjunctive therapy to prepare patient for thyroidectomy or radiation therapy or may be used in treatment of hyperthyroidism. Treatment from 6 mo to several yr may be necessary, usually averaging 1 yr.

Tapazole

(tăp′ə-zōl′)
A trademark for the drug methimazole.
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References in periodicals archive ?
These include Tapazole (methimazole) and PTU (propylthiouracil).
For the month of September, prescriptions of Levoxyl (up 25 percent), Tapazole (up 12 percent) and Cytomel (up 35 percent) continue to drive organic growth in the period," said Ellis.
3 million, Tapazole increing Soloxine and Tussigon were up approximately 21 percent to $2.
For the month of July, prescriptions of Levoxyl (up 23 percent), Tapazole (up 12 percent) and Cytomel (up 23 percent) continue to drive organic growth of 21 percent for the quarter," said Ellis.
0 million represents a 20 percent increase over 1997 and results from both unit and price increases in Levoxyl and Tapazole.
Prescriptions of Levoxyl (up 26 percent), Tapazole (up 13 percent) and Cytomel (up 29 percent) continue to drive organic growth of 22 percent for the quarter," said Ellis.
Third quarter sales of Endocrine products, including Levoxyl, Tapazole and Cytomel, totaled $14.
Sales of Endocrine products, including Levoxyl, Tapazole and Cytomel, reached a record level in the second quarter of 1998 totalling $17.
Sales of Endocrine products, including Levoxyl, Tapazole and Cytomel remained strong in the first quarter 1998 at $12.