Treatment of hyperthyroidism ~
Thionamides Iodide Betablockers
Property Radioactive
I
Carbimazole Propylthiouracil iodine
Mechanism Its a prodrug Its not a prodrug Inhibits release of stored Blunt Hypersensitivity of tissues Absorbed into thyroid gland
of action thyroxine to catecholamines and RAI-131 leads to the
Competitive Inhibitors of the I Competitive Inhibitors of
destruction of thyroid
thyroid peroxidase enzyme the thyroid peroxidase Reduces vascularity of the
follicular cells
(TPO) enzyme (TPO) gland – useful in surgery
decreases serum T3 by inhibition
Reduce peripheral conversion of of peripheral conversion of T4 to
T4 → T3 T3
Does not affect existing Does not affect existing
hormones in circulation hormones in circulation
Indications Graves’ disease-18-24 Uses to treat hyperthyroidism • Thyroid storm Initial symptomatic control as • Preferred therapy in most
months(not lifelong) in pregnant women during (Thyrotoxic crisis) adjunct to anti-thyroid drugs, patients with high-risk
1st trimester one to use • Onset of action quick comorbidities ; at high risk for
toxic multinodular goiter / placental crossing and (within 24 hours) surgery and need definitive
toxic nodules(until patient teratogenicity is rare compared Sole treatment in subacute management
become euthyroid ,then proceed to carbimazole/methimazole thyroiditis
for surgery Adjunct to anti-thyroid • Patients with
drugs prior to surgery contraindications for the use of
thionamides
To alleviate symptoms of Thyroid storm
hyperthyroidism
• Toxic MNG
Make a patient euthyroid in
preparation for • Grave’s disease: specially
Thyroid storm (Thyrotoxic crisis) relapsed disease
thyroidectomy (surgery) or
radioactive iodine therapy
• onset of action quicker than with
carbimazole
Thyrotoxicosis / thyroid storm
Contraindica- Past history of major adverse effects If beta blockers are
tions contraindicated Pregnancy
Baseline absolute neutrophil count <500/mm3
• non-dihydropyridine CCB eg. Females planning a pregnancy <
Hypersensitivity to drug diltiazem, verapamil 6/12
Breast feeding
Children
-
Thionamides Iodide Betablockers
Property Radioactive
I
Carbimazole Propylthiouracil iodine
Mechanism Its a prodrug Its not a prodrug Inhibits release of stored Blunt Hypersensitivity of tissues Absorbed into thyroid gland
of action thyroxine to catecholamines and RAI-131 leads to the
Competitive Inhibitors of the I Competitive Inhibitors of
destruction of thyroid
thyroid peroxidase enzyme the thyroid peroxidase Reduces vascularity of the
follicular cells
(TPO) enzyme (TPO) gland – useful in surgery
decreases serum T3 by inhibition
Reduce peripheral conversion of of peripheral conversion of T4 to
T4 → T3 T3
Does not affect existing Does not affect existing
hormones in circulation hormones in circulation
Indications Graves’ disease-18-24 Uses to treat hyperthyroidism • Thyroid storm Initial symptomatic control as • Preferred therapy in most
months(not lifelong) in pregnant women during (Thyrotoxic crisis) adjunct to anti-thyroid drugs, patients with high-risk
1st trimester one to use • Onset of action quick comorbidities ; at high risk for
toxic multinodular goiter / placental crossing and (within 24 hours) surgery and need definitive
toxic nodules(until patient teratogenicity is rare compared Sole treatment in subacute management
become euthyroid ,then proceed to carbimazole/methimazole thyroiditis
for surgery Adjunct to anti-thyroid • Patients with
drugs prior to surgery contraindications for the use of
thionamides
To alleviate symptoms of Thyroid storm
hyperthyroidism
• Toxic MNG
Make a patient euthyroid in
preparation for • Grave’s disease: specially
Thyroid storm (Thyrotoxic crisis) relapsed disease
thyroidectomy (surgery) or
radioactive iodine therapy
• onset of action quicker than with
carbimazole
Thyrotoxicosis / thyroid storm
Contraindica- Past history of major adverse effects If beta blockers are
tions contraindicated Pregnancy
Baseline absolute neutrophil count <500/mm3
• non-dihydropyridine CCB eg. Females planning a pregnancy <
Hypersensitivity to drug diltiazem, verapamil 6/12
Breast feeding
Children
-
