Letrozole

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Overview

What is Letrozole?

Letrozole Tablets, USP for oral administration contain 2.5 mg of letrozole, a nonsteroidal aromatase inhibitor (inhibitor of estrogen synthesis). It is chemically described as 4,4'-(1H-1,2,4-Triazol-1-ylmethylene)dibenzonitrile, and its structural formula is

Letrozole is a white to yellowish crystalline powder, practically odorless, freely soluble in dichloromethane, slightly soluble in ethanol, and practically insoluble in water. It has a molecular weight of 285.31 g/mol, molecular formula CHN, and a melting range of 184°C to 185°C.

Letrozoleis available as 2.5 mg tablets for oral administration.

Inactive Ingredients:

What does Letrozole look like?

What are the available doses of Letrozole?

2.5 mg tablets

What should I talk to my health care provider before I take Letrozole?

How should I use Letrozole?

Letrozole

The recommended dose of letrozole tablet is one 2.5 mg tablet administered once a day, without regard to meals.

What interacts with Letrozole?

Sorry No Records found

What are the warnings of Letrozole?

Sorry No Records found

What are the precautions of Letrozole?

Sorry No Records found

What are the side effects of Letrozole?

Sorry No records found

What should I look out for while using Letrozole?

What might happen if I take too much Letrozole?

Isolated cases of letrozole overdose have been reported. In these instances, the highest single dose ingested was 62.5 mg or 25 tablets. While no serious adverse reactions were reported in these cases, because of the limited data available, no firm recommendations for treatment can be made. However, emesis could be induced if the patient is alert. In general, supportive care and frequent monitoring of vital signs are also appropriate. In single-dose studies, the highest dose used was 30 mg, which was well tolerated; in multiple-dose trials, the largest dose of 10 mg was well tolerated.

Lethality was observed in mice and rats following single oral doses that were equal to or greater than 2,000 mg/kg (about 4,000 to 8,000 times the daily maximum recommended human dose on a mg/m basis); death was associated with reduced motor activity, ataxia and dyspnea. Lethality was observed in cats following single IV doses that were equal to or greater than 10 mg/kg (about 50 times the daily maximum recommended human dose on a mg/m basis); death was preceded by depressed blood pressure and arrhythmias.

How should I store and handle Letrozole?

Store at controlled room temperature 20° to 25°C (68° to 77°F) [see USP].Letrozole Tablets, USP 2.5 mg are dark yellow, round, biconvex, film-coated tablets engraved "APO" on one side, "LET" over "2.5" on the other side. They are supplied as follows:Bottles of 30s NDC 60505-3255-3Bottles of 100s NDC 60505-3255-1Bottles of 1,000s NDC 60505-3255-8 Store at 20°C to 25°C (68°F to 77°F) excursions permitted from 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature]. Protect from moisture.Dispense in tight, light-resistant containers.Letrozole Tablets, USP 2.5 mg are dark yellow, round, biconvex, film-coated tablets engraved "APO" on one side, "LET" over "2.5" on the other side. They are supplied as follows:Bottles of 30s NDC 60505-3255-3Bottles of 100s NDC 60505-3255-1Bottles of 1,000s NDC 60505-3255-8 Store at 20°C to 25°C (68°F to 77°F) excursions permitted from 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature]. Protect from moisture.Dispense in tight, light-resistant containers.Letrozole Tablets, USP 2.5 mg are dark yellow, round, biconvex, film-coated tablets engraved "APO" on one side, "LET" over "2.5" on the other side. They are supplied as follows:Bottles of 30s NDC 60505-3255-3Bottles of 100s NDC 60505-3255-1Bottles of 1,000s NDC 60505-3255-8 Store at 20°C to 25°C (68°F to 77°F) excursions permitted from 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature]. Protect from moisture.Dispense in tight, light-resistant containers.Letrozole Tablets, USP 2.5 mg are dark yellow, round, biconvex, film-coated tablets engraved "APO" on one side, "LET" over "2.5" on the other side. They are supplied as follows:Bottles of 30s NDC 60505-3255-3Bottles of 100s NDC 60505-3255-1Bottles of 1,000s NDC 60505-3255-8 Store at 20°C to 25°C (68°F to 77°F) excursions permitted from 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature]. Protect from moisture.Dispense in tight, light-resistant containers.Letrozole Tablets, USP 2.5 mg are dark yellow, round, biconvex, film-coated tablets engraved "APO" on one side, "LET" over "2.5" on the other side. They are supplied as follows:Bottles of 30s NDC 60505-3255-3Bottles of 100s NDC 60505-3255-1Bottles of 1,000s NDC 60505-3255-8 Store at 20°C to 25°C (68°F to 77°F) excursions permitted from 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature]. Protect from moisture.Dispense in tight, light-resistant containers.Letrozole Tablets, USP 2.5 mg are dark yellow, round, biconvex, film-coated tablets engraved "APO" on one side, "LET" over "2.5" on the other side. They are supplied as follows:Bottles of 30s NDC 60505-3255-3Bottles of 100s NDC 60505-3255-1Bottles of 1,000s NDC 60505-3255-8 Store at 20°C to 25°C (68°F to 77°F) excursions permitted from 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature]. Protect from moisture.Dispense in tight, light-resistant containers.Letrozole Tablets, USP 2.5 mg are dark yellow, round, biconvex, film-coated tablets engraved "APO" on one side, "LET" over "2.5" on the other side. They are supplied as follows:Bottles of 30s NDC 60505-3255-3Bottles of 100s NDC 60505-3255-1Bottles of 1,000s NDC 60505-3255-8 Store at 20°C to 25°C (68°F to 77°F) excursions permitted from 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature]. Protect from moisture.Dispense in tight, light-resistant containers.

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Clinical Information

Chemical Structure

No Image found

Clinical Pharmacology

The growth of some cancers of the breast is stimulated or maintained by estrogens. Treatment of breast cancer thought to be hormonally responsive (i.e., estrogen and/or progesterone receptor positive or receptor unknown) has included a variety of efforts to decrease estrogen levels (ovariectomy, adrenalectomy, hypophysectomy) or inhibit estrogen effects (antiestrogens and progestational agents). These interventions lead to decreased tumor mass or delayed progression of tumor growth in some women.

In postmenopausal women, estrogens are mainly derived from the action of the aromatase enzyme, which converts adrenal androgens (primarily androstenedione and testosterone) to estrone and estradiol. The suppression of estrogen biosynthesis in peripheral tissues and in the cancer tissue itself can therefore be achieved by specifically inhibiting the aromatase enzyme.

Letrozole is a nonsteroidal competitive inhibitor of the aromatase enzyme system; it inhibits the conversion of androgens to estrogens. In adult nontumor- and tumor-bearing female animals, letrozole is as effective as ovariectomy in reducing uterine weight, elevating serum LH, and causing the regression of estrogen-dependent tumors. In contrast to ovariectomy, treatment with letrozole does not lead to an increase in serum FSH. Letrozole selectively inhibits gonadal steroidogenesis but has no significant effect on adrenal mineralocorticoid or glucocorticoid synthesis.

Letrozole inhibits the aromatase enzyme by competitively binding to the heme of the cytochrome P450 subunit of the enzyme, resulting in a reduction of estrogen biosynthesis in all tissues. Treatment of women with letrozole significantly lowers serum estrone, estradiol and estrone sulfate and has not been shown to significantly affect adrenal corticosteroid synthesis, aldosterone synthesis, or synthesis of thyroid hormones.

Non-Clinical Toxicology

The concomitant use of oxybutynin with other anticholinergic drugs or with other agents which produce dry mouth, constipation, somnolence (drowsiness), and/or other anticholinergic-like effects may increase the frequency and/or severity of such effects.

Anticholinergic agents may potentially alter the absorption of some concomitantly administered drugs due to anticholinergic effects on gastrointestinal motility. This may be of concern for drugs with a narrow therapeutic index.

Mean oxybutynin chloride plasma concentrations were approximately 3 to 4 fold higher when oxybutynin chloride was administered with ketoconazole, a potent CYP3A4 inhibitor.

Other inhibitors of the cytochrome P450 3A4 enzyme system, such as antimycotic agents (e.g., itraconazole and miconazole) or macrolide antibiotics (e.g., erythromycin and clarithromycin), may alter oxybutynin mean pharmacokinetic parameters (i.e., C and AUC). The clinical relevance of such potential interactions is not known. Caution should be used when such drugs are co-administered.

Use of letrozole tablets may cause decreases in bone mineral density (BMD). Consideration should be given to monitoring BMD. Results of a safety study to evaluate safety in the adjuvant setting comparing the effect on lumbar spine (L2 to L4) BMD of adjuvant treatment with letrozole to that with tamoxifen showed at 24 months a median decrease in lumbar spine BMD of 4.1% in the letrozole arm compared to a median increase of 0.3% in the tamoxifen arm (difference = 4.4%) (<0.0001) . Updated results from the BMD substudy (MA-17B) in the extended adjuvant setting demonstrated that at 2 years patients receiving letrozole had a median decrease from baseline of 3.8% in hip BMD compared to a median decrease of 2.0% in the placebo group. The changes from baseline in lumbar spine BMD in letrozole and placebo treated groups were not significantly different .

In the adjuvant trial (BIG 1-98), the incidence of bone fractures at any time after randomization was 14.7% for letrozole and 11.4% for tamoxifen at a median follow-up of 96 months. The incidence of osteoporosis was 5.1% for letrozole and 2.7% for tamoxifen . In the extended adjuvant trial (MA-17), the incidence of bone fractures at any time after randomization was 13.3% for letrozole and 7.8% for placebo at a median follow-up of 62 months. The incidence of new osteoporosis was 14.5% for letrozole and 7.8% for placebo .

The following adverse reactions are discussed in greater detail in other sections of the labeling.

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Reference

This information is obtained from the National Institute of Health's Standard Packaging Label drug database.
"https://dailymed.nlm.nih.gov/dailymed/"

While we update our database periodically, we cannot guarantee it is always updated to the latest version.

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Disclaimer:

Overview

What is Letrozole?

What does Letrozole look like?

What are the available doses of Letrozole?

What should I talk to my health care provider before I take Letrozole?

How should I use Letrozole?

What interacts with Letrozole?

What are the warnings of Letrozole?

What are the precautions of Letrozole?

What are the side effects of Letrozole?

What should I look out for while using Letrozole?

What might happen if I take too much Letrozole?

How should I store and handle Letrozole?

Clinical Information

Chemical Structure

Clinical Pharmacology

Non-Clinical Toxicology

Reference

While we update our database periodically, we cannot guarantee it is always updated to the latest version.

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Letrozole

Overview

What is Letrozole?

What does Letrozole look like?

What are the available doses of Letrozole?

What should I talk to my health care provider before I take Letrozole?

How should I use Letrozole?

What interacts with Letrozole?

What are the warnings of Letrozole?

What are the precautions of Letrozole?

What are the side effects of Letrozole?

What should I look out for while using Letrozole?

What might happen if I take too much Letrozole?

How should I store and handle Letrozole?

Clinical Information

Chemical Structure

Clinical Pharmacology

Non-Clinical Toxicology

Reference

While we update our database periodically, we cannot guarantee it is always updated to the latest version.

Review

Rate this treatment and share your opinion

Helpful tips to write a good review:

Reason for Taking This Treatment

Click the stars to rate this treatment

Effectiveness (required)

Ease of Use (required)

Satisfaction (required)

Write a brief description of your experience with this treatment:

Optional Information

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