A1,
A2,
B,
C1,
C2,
D,
E,
F,
G-H,
I-K,
L,
M,
N,
O,
P1,
P2,
Q-R,
S,
T,
U-V,
W-Z
Tapazole Pharmacology, Pharmacokinetics, Studies, Metabolism - Methimazole
Tapazole Pharmacology, Pharmacokinetics, Studies, Metabolism - Methimazole
CLINICAL PHARMACOLOGY
Methimazole inhibits the synthesis
of thyroid hormones
and thus is effective in the treatment
of hyperthyroidism. The drug
does not inactivate
existing thyroxine and triiodothyronine
that are stored in the thyroid
or circulating in the blood
nor does it interfere with the effectiveness
of thyroid hormones
given by mouth or by injection.
The actions and use of methimazole
are similar to those of propylthiouracil. On a weight
basis, the drug is at least
10 times as potent as
propylthiouracil, but methimazole
may be less consistent in action.
Methimazole is readily absorbed from the gastrointestinal
tract. It is metabolized rapidly and requires frequent administration.
Methimazole is excreted in the urine.
In laboratory animals,
various regimens that continuously suppress thyroid function and
thereby increase TSH secretion
result in thyroid tissue
hypertrophy. Under such
conditions, the appearance
of thyroid and pituitary
neoplasms has also been reported. Regimens that have been studied
in this regard include antithyroid
agents as well as dietary
iodine deficiency, subtotal
thyroidectomy, implantation
of autonomous thyrotropic
hormonesecreting pituitary tumors, and administration
of chemical goitrogens.
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