Adverse effects include rash, allergic reactions, abnormal liver function including hepatic failure with propylthiouracil , and, in about 0. Patients allergic to one drug can be switched to the other, but cross-sensitivity may occur. If agranulocytosis occurs, the patient cannot be switched to the other drug; other therapy eg, radioiodine, surgery should be used.
Each drug has advantages and disadvantages. Methimazole has been used successfully in pregnant and nursing women without fetal or infant complications, but rarely methimazole has been associated with scalp and GI defects in neonates and with a rare embryopathy.
Because of these complications, propylthiouracil is used in the 1st trimester of pregnancy. The combination of high-dose propylthiouracil and dexamethasone, also a potent inhibitor of T4 to T3 conversion, can relieve symptoms of severe hyperthyroidism and restore the serum T3 level to normal within a week.
Symptoms and signs of hyperthyroidism due to adrenergic stimulation may respond to beta-blockers; propranolol has had the greatest use, but atenolol or metoprolol may be preferable. Other manifestations typically do not respond.
Manifestations typically responding to beta-blockers: Tachycardia, tremor, mental symptoms, eyelid lag; occasionally heat intolerance and sweating, diarrhea, proximal myopathy Manifestations typically not responding to beta-blockers: Treatment of Thyroid Storm. It rapidly decreases heart rate, usually within 2 to 3 h when given orally and within minutes when given IV.
Esmolol should be used in the ICU because it requires careful titration and monitoring. Beta-blockers are also indicated for tachycardia with hyperthyroidism, especially in elderly patients, because antithyroid drugs usually take several weeks to become fully effective.
Calcium channel blockers may control tachyarrhythmias in patients in whom beta-blockers are contraindicated. Iodine in pharmacologic doses inhibits the release of T3 and T4 within hours and inhibits the organification of iodine, a transitory effect lasting from a few days to a week, after which inhibition usually ceases. Iodine is used for emergency management of thyroid storm, for hyperthyroid patients undergoing emergency nonthyroid surgery, and because it also decreases the vascularity of the thyroid for preoperative preparation of hyperthyroid patients undergoing thyroidectomy.
Iodine generally is not used for routine treatment of hyperthyroidism. The usual dosage is 2 to 3 drops to mg of a saturated potassium iodide solution po tid or qid or sodium iodide in 1 L 0.
Complications of iodine therapy include inflammation of the salivary glands, conjunctivitis, and rash. In the US, I is the most common treatment for hyperthyroidism.
Radioiodine is often recommended as the treatment of choice for Graves disease and toxic nodular goiter in all patients, including children. Propranolol may cause a reduction in clearance and an increase in plasma concentrations of warfarin. Propranolol modifies the tachycardia of hypoglycaemia; caution should therefore be exercised in the concomitant use of propranolol and hypoglycaemic therapy in diabetic patients. Propranolol may prolong the hypoglycaemic response to insulin.
Beta-adrenoceptor blocking agents may exacerbate the rebound hypertension which can follow the withdrawal of clonidine. If the drugs are co-administered, the beta-adrenoceptor blocking drug should be withdrawn several days before discontinuing clonidine. If replacing clonidine with beta-adrenoceptor therapy the introduction of the beta-adrenoceptor blocking drug should be delayed for several days after clonidine administration has stopped.
Concomitant use of moxonidine and beta blockers may result in an enhanced hypotensive effect. Hypotensive effect may be enhanced when propranolol is taken with diuretics, methyldopa or levodopa. Prazosin or other alpha-adrenoreceptor blockers may potentiate postural hypotension, tachycardia and palpitations. Caution is necessary if ergotamine, dihydroergotamine or related compounds are given in combination with propranolol since vasospastic reactions have been reported in a few patients.
Propranolol inhibits the metabolism of rizatriptan which can significantly increases plasma concentration levels.
A dose reduction to 5mg is recommended. Administration should be separated by 2 hours. The metabolism of propranolol may be increased by potent liver enzyme inducer barbiturates. Concomitant administration of propranolol and chlorpromazine may result in an increase in plasma levels of both drugs. This may lead to an enhanced antipsychotic effect for chlorpromazine and an increased antihypertensive effect for propranolol. Concomitant use of cimetidine will increase, where as alcohol will decrease the plasma levels of propranolol.
Concomitant use of hydralazine will increase, where as alcohol will decrease the plasma levels of propranolol. Propranolol may cause plasma concentrations of imipramine to increase. The hypotensive effects of beta-blockers may be enhanced by MAOIs. NSAIDs notably indometacin, may cause an increase in blood pressure. This may be particularly significant in patients with poorly controlled hypertension. The metabolism of propranolol may be increased by potent liver enzyme inducer rifampicin.
Selective Serotonin Re-uptake Inhibitors: Fluvoxamine inhibits oxidative metabolism and increases plasma concentrations of propranolol. This may result in severe bradycardia. Propranolol reduces the clearance and consequentially increases the plasma concentration of theophylline.
Smoking tobacco may oppose the effects of beta blockers in the treatment of angina or hypotension. Patients should be encouraged to stop smoking, apart from its other toxic effects, it aggravates ocardial ischaemia, increases heart rate and can impair blood pressure control. If patient continues to smoke, dosage of the beta blocker may need to be increased or a cardio-selective beta blocker may be more appropriate. Interference with laboratory tests - Propranolol has been reported to interfere with the estimation of serum bilirubin by the diazo method and with the determination of catecholamines by methods using fluorescence.
There is no evidence of teratogenicity with propranolol. However beta-adrenoceptor blocking drugs reduce placental perfusion, which may result in intra-uterine foetal death, immature and premature deliveries.
In addition, adverse effects especially hypoglycaemia and bradycardia in the neonate and bradycardia in the foetus may occur. There is an increased risk of cardiac and pulmonary complications in the neonate in the post-natal period.
Breast-feeding Most beta-adrenoceptor blocking drugs, particularly lipophilic compounds, will pass into breast milk although to a variable extent. Breast feeding is therefore not recommended following administration of these compounds. However, patients should be warned that visual disturbances, hallucinations, mental confusion, dizziness, drowsiness or fatigue may occur and they should not drive or operate machinery if they feel affected.
D Relieve discomfort from headaches, abdominal distention, and skeletal pain. E Instruct the client on how to cough and deep breath postoperatively. B, C, D Feedback: Until the client has surgery or receives radiation treatment, nursing priorities include helping the client cope with changes in physical appearance; pacing activities to accommodate the client's fatigue; and relieving discomfort from headaches, abdominal distention resulting from organ enlargement, and skeletal pain.
The nurse is providing education to a client who will be having a hypophysectomy. What should the nurse be sure to include to preventing complications? A Lay in the supine flat position to avoid an increase in intracranial pressure. B Avoid drinking from a straw, sneezing, coughing, and bending over.
C When the packing is removed, you may blow your nose to clear the clot. D Brush teeth with a firm bristle toothbrush. Postoperatively, the client undergoes frequent neurologic assessments to detect signs of increased intracranial pressure and meningitis. If the client has nasal packing, the nurse monitors drainage from the nose and postnasal drainage for the presence of cerebrospinal fluid.
The nurse modifies oral and facial hygiene to promote cleanliness without contributing to trauma near the operative site. The nurse also reminds the client to avoid drinking from a straw, sneezing, coughing, and bending over to prevent dislodging the graft that seals the operative area between the cranium and nose.
An adult client has been diagnosed with a rare disorder, Simmonds' disease panhypopituitarism and placed on hormone replacements. What is important for the nurse to educate the client regarding about the medication? A The medication must be taken as ordered until surgery is scheduled to remove the tumor.
B Thyroid medication will be administered for the duration of the client's life.
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