| Drug Category: Antineoplastic Agent, Antiandrogen.
Dosing (Adults): Metastatic prostate cancer: Oral: 50 mg once daily (in combination with an LHRH analogue). Locally-advanced prostate cancer (unlabeled use): Oral: 150 mg once daily (as monotherapy).
When bicalutamide is combined with luteinizing hormone releasing hormone (LHRH) analog therapy, the suppression of serum testosterone induced by the LHRH analog is not affected. However, in clinical trials with bicalutamide as a single agent for prostate cancer, rises in serum testosterone and estradiol have been noted.
In a subset of patients who have been treated with bicalutamide and an LHRH agonist, and who discontinue bicalutamide therapy due to progressive advanced prostate cancer, a reduction in Prostate Specific Antigen (PSA) and/or clinical improvement (antiandrogen withdrawal phenomenon) may be observed.
Dosage adjustment in liver impairment: Limited data in subjects with severe hepatic impairment suggest that excretion of bicalutamide may be delayed and could lead to further accumulation. Use with caution in patients with moderate to severe hepatic impairment.
Supplied: 50 mg tablet.
| CLINICAL PHARMACOLOGY
In animal studies, flutamide demonstrates potent antiandrogenic effects. It exerts its antiandrogenic action by inhibiting androgen uptake and/or by inhibiting nuclear binding of androgen in target tissues or both. Prostatic carcinoma is known to be androgen-sensitive and responds to treatment that counteracts the effect of androgen and/or removes the source of androgen, eg, castration. Elevations of plasma testosterone and estradiol levels have been noted following flutamide administration.
INDICATIONS AND USAGE
Stage B2-C Prostatic Carcinoma
Stage D2 Metastatic Carcinoma
EULEXIN Capsules are contraindicated in patients with severe hepatic impairment (baseline hepatic enzymes should be evaluated prior to treatment).
Female hirsutism (unlabeled use): 250 mg daily
| Mechanism of Action
ZOLADEX is a synthetic decapeptide analogue of LHRH. ZOLADEX acts as a potent inhibitor of pituitary gonadotropin secretion when administered in the biodegradable formulation.
Following initial administration, ZOLADEX causes an initial increase in serum-luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels with subsequent increases in serum levels of testosterone. Chronic administration of ZOLADEX leads to sustained suppression of pituitary gonadotropins, and serum levels of testosterone consequently fall into the range normally seen in surgically castrated men approximately 21 days after initiation of therapy. This leads to accessory sex organ regression.
In animal and in in vitro studies, administration of goserelin resulted in the regression or inhibition of growth of the hormonally sensitive dimethylbenzanthracene (DMBA)-induced rat mammary tumor and Dunning R3327 prostate tumor.
In clinical trials using ZOLADEX 3.6 mg with follow-up of more than 2 years, suppression of serum testosterone to castrate levels has been maintained for the duration of therapy.
INDICATIONS AND USAGE
In controlled studies of patients with advanced prostatic cancer comparing ZOLADEX 3.6 mg to orchiectomy, the long-term endocrine responses and objective responses were similar between the two treatment arms. Additionally, duration of survival was similar between the two treatment arms in a major comparative trial.
In controlled studies of patients with advanced prostatic cancer, ZOLADEX 10.8 mg implant produced pharmacodynamically similar effect in terms of suppression of serum testosterone to that achieved with ZOLADEX 3.6 mg implant. Clinical outcome similar to that produced with the use of the ZOLADEX 3.6 mg implant administered every 28 days is predicted with the ZOLADEX 10.8 mg implant administered every 12 weeks.
Stage B2-C Prostatic Carcinoma:
The automatic safety feature of the syringe aids in the prevention of needlestick injury
3-month implant: 10.8 mg injected into the upper abdominal wall every 12 weeks
Note: Treatment should begin 8 weeks prior to radiotherapy in Stage B2-C prostate cancer; treatment may continue indefinitely
Breast cancer, endometriosis, endometrial thinning: Monthly implant: 3.6 mg injected into upper abdomen every 28 days
Note: For breast cancer, treatment may continue indefinitely; for endometriosis, it is recommended that duration of treatment not exceed 6 months. Only 1-2 doses are recommended for endometrial thinning.
Injection, solution, 3-month implant [disposable syringe; single-dose]: 10.8 mg [with 14-gauge hypodermic needle]
| CLINICAL PHARMACOLOGY
Leuprolide acetate, an LH-RH agonist, acts as a potent inhibitor of gonadotropin secretion when given continuously and in therapeutic doses. Animal and human studies indicate that following an initial stimulation of gonadotropins, chronic administration of leuprolide acetate results in suppression of ovarian and testicular steroidogenesis. This effect is reversible upon discontinuation of drug therapy. Administration of leuprolide acetate has resulted in inhibition of the growth of certain hormone dependent tumors (prostatic tumors in Noble and Dunning male rats and DMBA-induced mammary tumors in female rats) as well as atrophy of the reproductive organs.
In humans, subcutaneous administration of single daily doses of leuprolide acetate results in an initial increase in circulating levels of luteinizing hormone (LH) and follicle stimulating hormone (FSH), leading to a transient increase in levels of the gonadal steroids (testosterone and dihydrotestosterone in males, and estrone and estradiol in pre-menopausal females). However, continuous daily administration of leuprolide acetate results in decreased levels of LH and FSH. In males, testosterone is reduced to castrate levels. In pre-menopausal females, estrogens are reduced to post-menopausal levels. These decreases occur within two to four weeks after initiation of treatment, and castrate levels of testosterone in prostatic cancer patients have been demonstrated for periods of up to five years.
Leuprolide acetate is not active when given orally.
Endometriosis: I.M.: Initial therapy may be with leuprolide alone or in combination with norethindrone; if retreatment for an additional 6 months is necessary, norethindrone should be used. Retreatment is not recommended for longer than one additional 6-month course.
Lupron Depot®: 3.75 mg/month for up to 6 months or
Uterine leiomyomata (fibroids): I.M. (in combination with iron):
Injection, solution, as acetate (Lupron®): 5 mg/mL (2.8 mL) [contains benzyl alcohol; packaged with syringes and alcohol swabs]
Injection, powder for reconstitution, as acetate [depot formulation; prefilled syringe]:
Lupron Depot®: 3.75 mg, 7.5 mg [released over 1 month; contains polysorbate 80]
National Institutes of Health, U.S. National Library of Medicine, DailyMed Database.
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