Pricing
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Letrogen is indicated for:
Pharmacology
Mechanism of Action
Letrozole is a potent and highly specific nonsteroidal aromatase inhibitor. It works by binding to the haem of the cytochrome P450 part of the aromatase enzyme, which blocks the enzyme's action and cuts down estrogen production in all tissues. Letrozole's antitumour effect comes from starving estrogen-dependent breast cancer cells of the growth signal they need. In postmenopausal women, most estrogen comes from the aromatase enzyme, which converts adrenal androgens, mainly androstenedione and testosterone, into oestrone (E1) and oestradiol (E2). Blocking this enzyme specifically can reduce estrogen production in the peripheral tissues and in malignant tissues alike.
In healthy postmenopausal women, single doses of 0.1, 0.5 and 2.5 mg of letrozole lower serum oestrone and oestradiol by 75-78% and 78% from baseline respectively. The strongest suppression is reached within 48 to 78 hours. In postmenopausal patients with advanced breast cancer, daily doses of 0.1 to 5 mg lower plasma oestradiol, oestrone and oestrone sulphate by 78-95% from baseline in all patients treated. In healthy postmenopausal women, letrozole had no effect on plasma androgen levels (androstenedione and testosterone) after single doses of 0.1, 0.5 and 2.5 mg. This suggests that blocking estrogen production does not cause androgenic precursors to build up. No impairment of adrenal steroidogenesis has been seen.
Pharmacokinetics
Letrozole is absorbed quickly and completely from the gut, with an absolute bioavailability of 99.9%. Food slows absorption a little, but the total amount absorbed stays the same. This small effect on the speed of absorption is not thought to matter clinically, so letrozole can be taken before, with or after food. About 60% of letrozole binds to plasma proteins, mostly albumin (55%). Its concentration in red blood cells is about 80% of that in plasma. The main way the body clears letrozole is by converting it to a pharmacologically inactive carbinol metabolite. This process is fairly slow compared with blood flow through the liver. In the laboratory, the cytochrome P450 isoenzymes 3A4 and 2A6 can convert letrozole to this metabolite, but how much each one contributes in the body has not been established. The apparent terminal elimination half-life in plasma is about 2 days. With daily doses of 2.5 mg, steady-state levels are reached within 2 to 6 weeks.
Dosage Reference
Reference Information Only
Dosages shown are general references from official sources. Always consult your doctor or pharmacist for personalized dosing.
Adults:
Adults and elderly patients: The recommended dose is 2.5 mg of Letrozole taken once a day. In the adjuvant and extended adjuvant setting, treatment is continued for 5 years or until the tumor relapses, whichever happens first. In metastatic disease, treatment is continued until the tumor progresses. Elderly patients do not need a dose adjustment.
Patients with liver and/or kidney impairment: No dose adjustment is needed for patients with liver impairment or kidney impairment (creatinine clearance ≥10 mL/min). However, patients with severe liver impairment (Child-Pugh score C) should be monitored closely.
Children: Not applicable.
Side Effects
Common side effects of Letrozole are: plot flushes, increased level of cholesterol (hypercholesterolemia), fatigue, increased sweating, pain in bones and joints (arthralgia), skin rash, fleadache, dizziness, and malaise (generally feeling unwell). Gastrointestinal disorders also occur, such as nausea, vomiting, indigestion, constipation and diarrhea. Some people have an increase in or loss of appetite, and pain in muscles. Others have thinning or wasting of the bones (osteoporosis), which leads to bone fractures in some cases. Swelling of the arms, hands, feet and ankles (edema) can happen too. The list continues with depression, weight increase, flair loss, raised blood pressure (hypertension), abdominal pain, dry skin, vaginal bleeding, palpitations, rapid heart rate, joint stiffness (arthritis) and chest pain. Rare side effects are: nervous disorders such as anxiety, nervousness, irritability, drowsiness, memory problems, somnolence and insomnia. There is also pain or a burning sensation in the hands or wrist (carpal tunnel syndrome), and impairment of sensation, especially that of touch. Eye disorders such as blurred vision and eye irritation can occur. So can skin disorders such as itching (urticarial), vaginal discharge or dryness, and dryness of the mucous membranes. Other rare effects are weight decrease, urinary tract infection, increased frequency of urination, cough, increased level of enzymes, yellowing of the skin and eyes, and high blood levels of bilirubin (a breakdown product of red blood cells).
Cautions & Contraindications
Warnings & Precautions
In patients with breast cancer who have moderate liver impairment, no dose change is needed, but caution is advised because Letrova is cleared from the body mainly through the liver's own metabolism. Kidney impairment (calculated creatinine clearance of 20 to 50 ml/min) did not change the steady-state plasma level of Letrova at a dose of 2.5 mg or 5 mg, so no dose adjustment is needed for this degree of kidney impairment either. Letrova is weakly bound to plasma proteins, so it is expected that dialysis could remove it from the blood. Before prescribing Letrova to such patients, the potential risks and benefits should be weighed carefully. Fatigue and dizziness have been seen in some people taking Letrova. For that reason, patients should be told that their physical or mental ability to operate machinery or drive a car may be affected.
Contraindications
Letrozole should not be used by anyone with a known or suspected hypersensitivity to letrozole, to other aromatase inhibitors, or to any of the ingredients it contains. It is not to be used during pregnancy or while breastfeeding, and it is not suitable for women who have not yet reached menopause. It should also be avoided by patients with severe liver impairment.
Pregnancy & Breastfeeding
Oral letrozole caused teratogenic effects and maternal toxicity in pregnant rats at a dose of 0.03 mg/kg, with embryotoxicity, foetotoxicity, and a higher rate of foetal malformation appearing at doses above 0.003 mg/kg. As there are no adequate, well-controlled studies of letrozole in pregnant women, it is not recommended for use in this group. Whether letrozole passes into human breast milk is unknown, but since many medicines do pass into breast milk, it should not be given to a breastfeeding mother.
⚠️ Talk to your doctor before taking any medicine during pregnancy or while breastfeeding.
Overdose
No one has reported any experience of overdosage with Letrozole. There is no specific antidote. Letrozole is not highly protein-bound, so dialysis may help. If the patient is alert, vomiting may be induced. Otherwise, supportive care and frequent checks of vital signs are appropriate.
⚠️ In an emergency call 999 or go to the nearest hospital emergency department.
Storage
Store Letrozole below 30°C, and keep it away from light and moisture. Keep it out of the reach of children.
Drug Interactions
Common questions about Letrogen 2.5 mg
What is Letrogen 2.5 mg Tablet?
Letrogen 2.5 mg Tablet is a medicine that contains Letrozole. It is made by Ibn Sina Pharmaceutical Ind. Ltd. It belongs to the Hormonal Chemotherapy group of medicines.
What is Letrogen used for?
Letrogen is used for: Cancer.
What are the side effects of Letrogen?
Common side effects of Letrozole are: plot flushes, increased level of cholesterol (hypercholesterolemia), fatigue, increased sweating, pain in bones and joints (arthralgia), skin rash, fleadache, dizziness, and malaise (generally feeling unwell). Gastrointestinal disorders also occur, such as nausea, vomiting, indigestion, constipation and diarrhea.
Can I take Letrogen during pregnancy or while breastfeeding?
Oral letrozole caused teratogenic effects and maternal toxicity in pregnant rats at a dose of 0.03 mg/kg, with embryotoxicity, foetotoxicity, and a higher rate of foetal malformation appearing at doses above 0.003 mg/kg. As there are no adequate, well-controlled studies of letrozole in pregnant women, it is not recommended for use in this group. Talk to your doctor before taking any medicine during pregnancy or while breastfeeding.
What happens if I take too much Letrogen?
No one has reported any experience of overdosage with Letrozole. There is no specific antidote. In an emergency call 999 or go to the nearest hospital emergency department.
How should I store Letrogen?
Store Letrozole below 30°C, and keep it away from light and moisture. Keep it out of the reach of children.
Can I take other medicines with Letrogen?
Some medicines can interact with Letrozole, for example: Cimetidine, Warfarin Sodium. Tell your doctor or pharmacist about every medicine you take.
Is there a cheaper medicine with the same ingredient?
Letrogen is already among the lowest-priced brands of Letrozole at this strength.
Do I need a prescription for Letrogen?
Letrogen is a prescription (Rx) medicine. Take it as your doctor advises.