Thyroid and Antithyroid Drugs Flashcards
Levothyroxine (t4, Synthroid)
Functional Classification
Thyroid Hormone
Levothyroxine (t4, Synthroid)
Mechanism of Action
Increases metabolic rate; controls protein synthesis; increases cardiac output, renal blood flow, O2 consumption, body temp, blood volume, growth, development at cellular level via action on thyroid hormone receptors
Levothyroxine (t4, Synthroid)
Uses
Hypothyroidism, myxedema coma, thyroid hormone replacement, thyrotoxicosis, congenital hypothyroidism, some types of thyroid cancer, pituitary TSH suppression
Levothyroxine (t4, Synthroid)
Contraindications
Adrenal insufficiency, recent MI, thyrotoxicosis, hypersensitivity to beef, alcohol intolerance (inj only)
Obesity treatment
Levothyroxine (t4, Synthroid)
Side Effects
CNS: Anxiety, Insomnia, Tremors, headache, THYROID STORM, excitability
CV: Tachycardia, Palpitations, Angina, Dysrhythmias, hypertension, CARDIAC ARREST
GI: nausea, diarrhea, increased or decreased appetite, cramps
MISC: Menstrual irregularities, weight loss, sweating, heat intolerance, fever, alopecia, decreased bone mineral density
Levothyroxine (t4, Synthroid)
Nursing Considerations
ASSESS:
- BP, pulse periodically during treatment
- Weight daily in same clothing, using same scale, at same time of day
- Height, growth rate of child
- T3,T4, FTIs, which are decreased; radioimmunoassay of TSH, which is increased; radio uptake, which is increased if patient receiving too low a dose of medication
- PT may require decreased anticoagulant; check for bleeding, bruising
- Increased nervousness, excitability, irritability, which may indicate too high a dose of medication, usually after 1-3 wk of treatment
- Cardiac Status: angina, palpitation, chest pain, change in VS
PERFORM/PROVIDE
-Withdrawal of medication 4 wk before RAIU test
Propylthiouracil
Functional Classification
Thyroid hormone antagonist (antithyroid)
Propylthiouracil
Chemical Classification
Thioamide
Propylthiouracil
Mechanism of Action
Blocks synthesis peripherally of T3, T4 (triiodothyronine, thyroxine), inhibits organification of iodine
Propylthiouracil
Uses
Preparation for thyroidectomy, thyrotoxic crisis, hyperthyroidism, thyroid storm
Propylthiouracil
Contraindications
Pregnancy (D), breastfeeding, hypersensitivity, agranulocytosis, hepatitis, jaundice
Propylthiouracil
Side Effects
CNS: Drowsiness, Headache, Vertigo, Fever, paresthesias, neuritis
GI: Nausea, Diarrhea, Vomiting, JAUNDICE, HEPATITIS, loss of taste, LIVER FAILURE, DEATH
GU: NEPHRITIS
HEMA: AGRANULOCYTOSIS, LEUKOPENIA, THROMBOCYTOPENIA, HYPOTHROMBINEMIA, LYMPHADENOPATHY, bleeding, vasculitis, periarteritis
INTEG: Rash, Urticaria, Pruritus, Alopecia, Hyperpigmentation, lupuslike syndrome
MS: myalgia, arthralgia, nocturnal muscle cramps, osteoporosis
Propylthiouracil
Nursing Considerations
ASSESS:
- HYPERTHYROIDISM: weight loss, nervousness, insomnia, fever, diaphoresis, tremors; HYPOTHYROIDISM: constipation, dry skin, weakness, headache
- Pulse, BP, temp
- I&O ratio; check for edema: puffy hands, feet, periorbits; indicates hypothyroidism
- Weight daily; same clothing, scale, time of day
- T3,T4, which are increased; serum TSH, which is decreased; free thyroxine index, which is increased if dosage is too low; discontinue product 3-4wk before RAIU
- BLOOD DYSCRASIAS: CBC with differential; leukopenia, thrombocytopenia, agranulocytosis
- OVERDOSE: peripheral edema, heat intolerance, diaphoresis, palpitations, dysrhythmias, severe tachycardia, increased temp, delirium, CNS irritability
- HYPERSENSITIVITY: rash, enlarged cervical lymph nodes; product may have to be discontinued
- HYPOPROTHROMBINEMIA: bleeding petechiae, ecchymosis
- Clinical response: after 3wk should include increased weight, pulse; decreased T4
- BONE MARROW SUPPRESSION: sore throat fever, fatigue
- HEPATOTOXICITY: LFTs before, during treatment; jaundice, nausea, vomiting, abdominal pain, anorexia diarrhea, fatigue
PERFORM/PROVIDE:
-Fluids 3-4L/day unless contraindicated
Levothyroxine (t4, Synthroid)
Chemical Classification
Levoisomer of thyroxine
