Hypothyroidism drug-induced

Drug-induced hypothyroidism (Table 38-3) can be satisfactorily managed with levothyroxine therapy if the offending agent cannot be stopped. In the case of amiodarone-induced hypothyroidism, levothyroxine therapy may be necessary even after discontinuance because of amiodarone s very long half-life. 

Vagenakis AG, Braverman LE. Drug induced hypothyroidism. Pharmacol Ther (C) 1976 1 149. 

Gomolin IH. Iodinated glycerol-induced hypothyroidism. Drug Intell Clin Pharm 1987 21(9) 726-7. 

The authors suggested that men with primary hypothyroidism may be particularly sensitive to neuroleptic drug-induced increases in prolactin concentrations. 

In patients with hyperthyroidism, the metabolic clearances of T4 and T3 are increased and the half-lives decreased the opposite is true in patients with hypothyroidism. Drugs that induce hepatic... 

Hypothyroidism is a relative deficiency in thyroid hormones. It manifests as a slowing down of all body functions or a decrease in metabolic rate. There are many causes for hypothyroidism, including Hashimoto s thyroiditis, drug-induced, radiation and radioactive iodine, dyshormono-genesis, congenital, and secondary causes (pituitary or... 

Several conditions or drugs may induce an elevation of TSH in the absence of hypothyroidism (Table 106.3). In patients with severe nonthyroidai illnesses TSH may be suppressed because of the disease process, or because of medications such as glucocorticoids, dopamine and dob-utamine. This illness- or drug-induced suppression of TSH may mask a mild primary hypothyroidism. On the contrary, during the recovery phase of a severe nonthyroidai illness, TSH may be transiently elevated. 

The theophylline elimination rate constant after a single intravenous dose of aminophylline was found to be greater in hyperthyroid patients (0.155 h ) than in euthyroid (0.107 h ) or hypothyroid patients (0.060 h ) some other pharmacokinetic parameters were also changed. The authors concluded that thyroid dysfunction may modestly alter theophylline requirements. It is therefore also likely that drug-induced changes in the thyroid status, such as those caused by amiodarone, may also alter the amount of theophylline needed to maintain therapeutic levels. 

Causes of constipation in infants and children include functional constipation, neurogenic constipation [aganglionosis, hypoganglionosis, neuronal intestinal dysplasia (NID)], chronic intestinal pseudo-obstruction, disorders of the spinal cord, cerebral palsy, constipation secondary to anal fissures and strictures, neonatal hypothyroidism and drug induced constipation (Potter 1998). 

Lithium is concentrated in the thyroid gland and can impair thyroid hormone synthesis. Although goiter is uncommon, as many as 30% of patients develop at least transiently elevated thyroid-stimulating hormone values. Lithium-induced hypothyroidism is not usually an indication to discontinue the drug. Patients can be supplemented with levothyroxine if continuation of lithium is desired.30... 

The answer is d. (Hardman, pp 1398-MOO.) Methimazole is classified as a thioamide and is used in the treatment of hyperthyroidism It prevents the organification of F by blocking the oxidation of F to active I and also inhibits coupling of iodotyrosines. Excessive treatment with this drug may induce hypothyroidism. Some other adverse reactions reported for... 

Amiodarone may induce thyrotoxicosis (2% to 3% of patients) or hypothyroidism. It interferes with type I 5 -deiodinase, leading to reduced conversion of T4 to T3, and iodide release from the drug may contribute to iodine excess. Amiodarone also causes a destructive thyroiditis with loss of thyroglobulin and thyroid hormones. 

Lithium carbonate, administered for affective and bipolar disorders, may enhance the effects of antithyroid drugs. Potassium iodide, used as an expectorant, is a major ingredient in many cough medications. Iodide derived from this source may enhance the effects of antithyroid drugs and lead to iodine-induced hypothyroidism. Iodine in topical antiseptics and radiological contrast agents may act in a similar manner. 

Sunirinib (Sutent) [Kinase Inhibitor] Uses Advanced GI stromal tumor refractory/intolerant of imatinib advanced RCC Action Kinase inhibitor Dose Adults. 50 mg PO daily x 4 wk, followed by 2 wk holiday = 1 cycle 4- to 37.5 mg w/ CYP3A4 inhibitors (Table VI-8), to T 87.5 mg w/ CYP3A4 inducers Contra w/ atazanavir Caution [D, -] Multiple interactions require dose modification (eg, St. John s wort) Disp Caps SE -l WBC pit, bleeding, T BP, -l ejection fraction, T QT interval, pancreatitis, DVT, Sz, adrenal insuff, N/V/D, skin discoloration, oral ulcers, taste perversion, hypothyroidism Interactions Multiple interactions require dose modification (eg, St. John s wort) EMS Monitor ECG for T QT interval grapefruit juice may T adverse effects may affect potassium level (hypo-/hyperkalemia) monitor for S/Sxs of heart failure drug can 4- ejection fraction OD May cause abd pain, muscle weakness, and chills symptomatic and supportive... 

In another study, three patients with type 1 disease, two of whom had not responded to methimazole plus perchlorate, were successfully treated with a short course of iopanoic acid 1 g/day, resulting in a marked reduction in the peripheral conversion of T4 to T3 (153). Euthyroidism was restored in 7-12 days, allowing uneventful thyroidectomy. The patients were then treated with levothyroxine for hypothyroidism and amiodarone was safely restarted. The authors suggested that iopanoic acid is the drug of choice for rapid restoration of normal thyroid function before thyroidectomy in patients with drug-resistant type 1 amiodarone-induced hyperthyroidism. 

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