Applicant/PHRC: Hetero Drugs South Africa (Pty) Ltd
Product proprietary name: HETERO LETROZOLE 2,5 mg
Dosage form and strength: Film coated tablet contains 2,5 mg letrozole
aldosterone, 11-deoxycortisol, 17-hydroxy-progesterone, and ACTH or in plasma renin activity among
postmenopausal patients treated with a daily dose of letrozole, 0,1 to 5 mg. The ACTH stimulation
test performed after 6 and 12 weeks of treatment with daily doses of 0,1 mg, 0,25 mg, 0,5 mg, 1 mg,
2,5 mg and 5 mg did not indicate any attenuation of aldosterone or cortisol production. Thus,
glucocorticoid and mineralocorticoid supplementation is not necessary.
No changes were noted in plasma concentrations of androgens (androstenedione and testosterone)
among healthy postmenopausal women after 0,1 mg, 0,5 mg and 2,5 mg single doses of letrozole or
in plasma concentrations of androstenedione among postmenopausal patients treated with daily
doses of 0,1 to 5 mg, indicating that the blockade of oestrogen biosynthesis does not lead to
accumulation of androgenic precursors. Plasma levels of LH and FSH are not affected by letrozole in
patients, nor are thyroid function as evaluated by TSH, T4 and T3 uptake.
5.2 Pharmacokinetic properties:
Absorption
Letrozole is rapidly and completely absorbed from the gastrointestinal tract (mean absolute
bioavailability: 99,9 %). Food slightly decreases the rate of absorption but the extent of absorption
(AUC) is not changed. The minor effect on the absorption rate is not considered to be of clinical
relevance and therefore letrozole may be taken without regard to mealtimes.
Distribution
Plasma protein binding of letrozole is approximately 60 %, mainly to albumin (55 %). The
concentration of letrozole in erythrocytes is about 80 % of that in plasma. After administration of 2,5
mg 14C-Iabelled letrozole, approximately 82 % of the radioactivity in plasma was unchanged
compound. Systemic exposure to metabolites is therefore low. Letrozole is rapidly and extensively
distributed to tissues. Its apparent volume of distribution at steady state is about 1,87 ± 0,47 ℓ/kg.
June 2022
Initials……KB……….
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