Bicalutamide

Pharmaceuticals

Pharmaceuticals -> Antineoplastic and immunomodulating agents -> Antineoplastic agents

Pharmaceutical

Crystals from 1:1 (v/v) mix of ethyl acetate and petroleum ether

Fine white to off-white powder

Slightly soluble in chloroform and absolute ethanol; sparingly soluble in methanol; soluble in acetone and tetrahydrofuan

Practically insoluble in water at 37 °C (5 mg/1000 mL)

9.28e-03 g/L

FDA approved drugs -> Active ingredient

FDA approved drugs -> Active ingredient

Hormones and antihormones

191-193 °C

191-193 °C

191 - 193 °C

Warning

H315 (88.4%): Causes skin irritation [Warning Skin corrosion/irritation]

P203, P261, P264, P264+P265, P271, P280, P302+P352, P304+P340, P305+P351+P338, P318, P319, P321, P332+P317, P337+P317, P362+P364, P403+P233, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 138 reports by companies from 17 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

The Approved Drug Products with Therapeutic Equivalence Evaluations List identifies currently marketed prescription drug products, incl bicalutamide, approved on the basis of safety and effectiveness by FDA under sections 505 of the Federal Food, Drug, and Cosmetic Act.

/PRECAUTIONS FOR ANTINEOPLASTIC AGENTS:/ Methods for transporting hazardous drugs to the health-care setting should be consistent with environmental protection and national or local regulations for transporting hazardous substances. When hazardous drugs are being transported to the home-care setting, appropriate containers (eg, lined cardboard boxes) and procedures should be used to prevent breakage and contain leakage. ... The drugs must be securely capped or sealed and properly packaged and protected during transport to reduce further the chance of breakage and spillage in a public area such as a corridor or elevator. /Antineoplastic agents/

/PRECAUTIONS FOR ANTINEOPLASTIC AGENTS:/ Spill kits containing all materials needed to clean up spills of hazardous drugs should be assembled or purchased. These kits should be readily available in all areas where hazardous drugs are routinely handled. If hazardous drugs are being prepared or administered in a nonroutine area (home setting or unusual patient-care area), a spill kit should be obtained by the drug handler. The kit should include two pairs of disposable gloves (one outer pair of utility gloves and one inner latex pair); low-permeability, disposable protective garments (coveralls or gown and shoe covers); safety glasses or splash goggles; respirator; absorbent, plastic-backed sheets or spill pads; disposable toweling; at least 2 sealable thick plastic hazardous waste disposal bags (prelabeled with an appropriate warning label); a disposable scoop for collecting glass fragments; and a puncture-resistant container for glass fragments. All individuals who routinely handle hazardous drugs must be trained in proper spill management and cleanup procedures. Spills and breakages must be cleaned up immediately according to the following procedures. If the spill is not located in a confined space, the spill area should be identified and other people should be prevented from approaching and spreading the contamination. Wearing protective apparel from the spill kit, workers should remove any broken glass fragments and place them in the puncture-resistant container. Liquids should be absorbed with a spill pad; powder should be removed with damp disposable gauze pads or soft toweling. The hazardous material should be completely removed and the area rinsed with water and then cleaned with detergent. The spill cleanup should proceed progressively from areas of lesser to greater contamination. The detergent should be thoroughly rinsed and removed. All contaminated materials should be placed in the disposal bags provided and sealed and transported to a designated containment receptacle. Spills occurring in the biohazard cabinet should be cleaned up immediately; a spill kit should be used if the volume exceeds 150 ml or the contents of one drug vial or ampule. If there is broken glass, utility gloves should be worn to remove it and place it in the puncture-resistant container located in the biohazard cabinet. The biological safety cabinet, including the drain spillage trough, should be thoroughly cleaned. If the spill is not easily and thoroughly contained, the biological safety cabinet should be decontaminated after cleanup. If the spill contaminates the high efficiency particulate air filter, use of the biological safety cabinet should be suspended until the cabinet has been decontaminated and the high efficiency particulate air filter replaced. /Antineoplastic agents/

/PRECAUTIONS FOR ANTINEOPLASTIC AGENTS:/ If hazardous drugs are routinely prepared or administered in carpeted areas, special equipment is necessary to remove the spill. Absorbent powder should be substituted for pads or sheets and left in place on the spill for the time recommended by the manufacturer. The powder should then be picked up with a small vacuum unit reserved for hazardous drug cleanup. The carpet should then be cleaned according to usual procedures. The vacuum bag should be removed and discarded or cleaned, and the exterior of the vacuum cleaner should be washed with detergent and rinsed before being covered and stored. The contaminated powder should be discarded into a sealable plastic bag and segregated with other contaminated waste materials. Alternatively, inexpensive wet or dry vacuum units may be purchased for this express use and used with appropriate cleaners. All such units are contaminated, once used, and must be cleaned, stored, and ultimately discarded /properly/ ... The circumstances and handling of spills should be documented. Health-care personnel exposed during spill management should also complete an incident report or exposure form. /Antineoplastic agents/

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

/PRECAUTIONS FOR ANTINEOPLASTIC AGENTS:/ All contaminated disposables should be contained in sealable bags for transfer to larger waste containers. /Antineoplastic agents/

/PRECAUTIONS FOR ANTINEOPLASTIC AGENTS:/ All bottles must be discarded as contaminated waste after decontamination of the biohazard cabinet. All protective apparel (gown, gloves, goggles, and respirator) should be discarded as contaminated waste. /Antineoplastic agents/

/PRECAUTIONS FOR ANTINEOPLASTIC AGENTS:/ The contaminated filters must be removed, bagged in thick plastic and prepared for disposal in a hazardous waste dump site or incinerator licensed by the Environmental Protection Agency (EPA). /Antineoplastic agents/

For more Disposal Methods (Complete) data for BICALUTAMIDE (8 total), please visit the HSDB record page.

/PRECAUTIONS FOR ANTINEOPLASTIC AGENTS:/ Accidental contamination of the health-care environment, resulting in exposure of personnel, patients, visitors, and family members to hazardous substances, is prevented by maintaining the physical integrity and security of packages of hazardous drugs. 1. Access to all areas where hazardous drugs are stored is limited to specified authorized staff. 2. A method should be present for identifying to personnel those drugs that require special precautions (eg, cytotoxics). One way to accomplish this is to apply appropriate warning labels to all hazardous drug containers, shelves, and bins where the drug products are stored. ... 3. A method of identifying, for patients and family members, those drugs that require special precautions in the home should be in place. This may be accomplished in the health-care setting, by providing specific labeling for discharge medications, along with written instructions. 4. Methods for identifying shipping cartons of hazardous drugs should be required from manufacturers and distributors of these drugs. 5. Written procedures for handling damaged packages of hazardous drugs should be maintained. Personnel involved in shipping and receiving hazardous drugs should be trained in these procedures, including the proper use of protective garments and equipment. Damaged shipping cartons of hazardous drugs should be received and opened in an isolated area (eg, in a laboratory fume hood, if available, not in a vertical laminar airflow biological safety cabinet used for preparing sterile products). /Antineoplastic agents/

/PRECAUTIONS FOR ANTINEOPLASTIC AGENTS:/ Facilities (eg, shelves, carts, counters, and trays) for storing hazardous drugs are designed to prevent breakage and to limit contamination in the event of leakage. Bins, shelves with barriers at the front, or other design features that reduce the chance of drug containers falling to the floor should be used. Hazardous drugs requiring refrigeration should be stored separately from nonhazardous drugs in individual bins designed to prevent breakage and to contain leakage. /Antineoplastic agents/

/PRECAUTIONS FOR ANTINEOPLASTIC AGENTS:/ Until the reproductive risks (or lack thereof) associated with handling hazardous drugs within a safety program have been substantiated, staff who are pregnant or breast-feeding should be allowed to avoid contact with these drugs. Policies should be in effect that provide these individuals with alternative tasks or responsibilities if they so desire. /Antineoplastic agents/

/PRECAUTIONS FOR ANTINEOPLASTIC AGENTS:/ The pharmacy should provide access to information on toxicity, treatment of acute exposure (if available), chemical inactivators, solubility and stability of hazardous drugs (including investigational agents) used in the workplace. /Antineoplastic agents/

For more Preventive Measures (Complete) data for BICALUTAMIDE (19 total), please visit the HSDB record page.

/PRECAUTIONS FOR ANTINEOPLASTIC AGENTS:/ Protective apparel: Disposable closed-front gown or coveralls, disposable utility gloves over disposable latex gloves, NIOSH-approved air-purifying half-mask respirator equipped with a high efficiency filter, and eye protection should be worn. /Antineoplastic agents/

/PRECAUTIONS FOR ANTINEOPLASTIC AGENTS:/ Class 100 clean-air work stations, both horizontal and vertical airflow (with no containment characteristics), are inappropriate engineering controls for handling hazardous drugs because they provide no personnel protection and permit environmental contamination. Although there are no engineering controls designed specifically for the safe handling of hazardous chemicals as sterile products, Class II contained vertical-flow biological safety cabinets (biohazard cabinets) have been adopted for this use. Biohazard cabinetry is, however, designed for the handling of infectious agents, not hazardous chemicals. ... Based on design, ease of use, and cost considerations, Class II contained-vertical-flow biohazard cabinetry is currently recommended for use in preparing sterile doses of hazardous drugs. Class II cabinetry design and performance specifications are defined in NSF Standard 49. Biological safety cabinets selected for use with hazardous drugs should meet NSF Standard 49 specifications to ensure the maximum protection from these engineering controls. /Antineoplastic agents/

/PRECAUTIONS FOR ANTINEOPLASTIC AGENTS:/ Workers should wear powder free, disposable surgical latex gloves of good quality when preparing hazardous drugs. Selection criteria for gloves should include thickness (especially at the fingertips where stress is the greatest), fit, length, and tactile sensation. ... The practice of double gloving is supported by research that indicates that many glove materials vary in drug permeability even within lots; therefore, double gloving is recommended. ... In general, surgical latex gloves fit better, have appropriate elasticity for double gloving and maintaining the integrity of the glove-gown interface, and have sufficient tactile sensation (even during double gloving) for stringent aseptic procedures. ... Powdered gloves should be avoided. /Antineoplastic agents/

/PRECAUTIONS FOR ANTINEOPLASTIC AGENTS:/ Workers who are not protected by the containment environment of a biohazard cabinet should use respiratory protection when handling hazardous drugs. Respiratory protection should be an adjunct to and not a substitute for engineering controls. Surgical masks of all types provide no respiratory protection against powdered or liquid aerosols of hazardous drugs. In situations where workers may be exposed to potential eye contact with hazardous drugs, an appropriate plastic face shield or splash goggles should be worn. /Antineoplastic agents/

/PRECAUTIONS FOR ANTINEOPLASTIC AGENTS:/ During compounding of hazardous drugs (eg, crushing, dissolving, and preparing an ointment), workers should wear low permeability gowns and double gloves. Compounding should take place in a protective area such as a disposable glove box. If compounding must be done in the open, an area away from drafts and traffic must be selected, and the worker should use appropriate respiratory protection. /Antineoplastic agents/

In vitro protein-binding studies have shown that bicalutamide can displace coumarin anticoagulants from binding sites. Prothrombin times should be closely monitored in patients already receiving coumarin anticoagulants who are started on /bicalutamide/.

In vitro studies have shown that R-bicalutamide is an inhibitor of CYP 3A4 with lesser inhibitory effects on CYP 2C9, 2C19 and 2D6 activity. Clinical studies have shown that with co-administration of bicalutamide, mean midazolam (a CYP 3A4 substrate) levels may be increased 1.5 fold (for Cmax) and 1.9 fold (for AUC). Hence, caution should be exercised when bicalutamide is co-administered with CYP 3A4 substrates.

Bicalutamide therapy is associated with mild, asymptomatic and transient elevations in serum aminotransferase levels in approximately 6% of patients. The frequency and height of the ALT elevations appears to be less with bicalutamide than flutamide. Similarly, there have been rare case reports of clinically apparent liver injury due to bicalutamide, but less frequently than with flutamide. In the Spanish pharmacovigilance study, there were 11 reports of hepatotoxicity from bicalutamide, none of which were fatal. On the other hand, the product label for bicalutamide mentions that a few cases of fatal hepatic failure have been reported. The clinical pattern of liver injury with bicalutamide appears to resemble that of flutamide. The latency to onset is usually 2 to 3 months, but can be shorter with reexposure and occasionally arises 4 to 6 months after starting. The typical pattern of serum enzyme elevations is hepatocellular and severe, fulminant cases have been described. Rash, fever and eosinophilia are not common and autoantibody formation is not described.

Bicalutamide competes with androgen for the binding of androgen receptors, consequently blocking the action of androgens of adrenal and testicular origin which stimulate the growth of normal and malignant prostatic tissue. Organic nitriles decompose into cyanide ions both in vivo and in vitro. Consequently the primary mechanism of toxicity for organic nitriles is their production of toxic cyanide ions or hydrogen cyanide. Cyanide is an inhibitor of cytochrome c oxidase in the fourth complex of the electron transport chain (found in the membrane of the mitochondria of eukaryotic cells). It complexes with the ferric iron atom in this enzyme. The binding of cyanide to this cytochrome prevents transport of electrons from cytochrome c oxidase to oxygen. As a result, the electron transport chain is disrupted and the cell can no longer aerobically produce ATP for energy. Tissues that mainly depend on aerobic respiration, such as the central nervous system and the heart, are particularly affected. Cyanide is also known produce some of its toxic effects by binding to catalase, glutathione peroxidase, methemoglobin, hydroxocobalamin, phosphatase, tyrosinase, ascorbic acid oxidase, xanthine oxidase, succinic dehydrogenase, and Cu/Zn superoxide dismutase. Cyanide binds to the ferric ion of methemoglobin to form inactive cyanmethemoglobin. (L97)

/PRECAUTIONS FOR ANTINEOPLASTIC AGENTS:/ There is no method available for routine monitoring of personnel for evidence of hazardous drug exposure. Tests for the presence of mutagens or chromosomal damage are not drug specific and are of value only in controlled studies. Chemical analysis of urine for the presence of hazardous drugs at the sensitivity level needed to detect occupational exposure is limited to a few drugs and is not yet commercially available. /Antineoplastic agents/

/HUMAN EXPOSURE STUDIES/ ... Sixteen patients with prostatic cancer (stage C to D) were given 10, 30, 50, 80 or 100 mg of bicalutamide orally daily for 12 weeks. Adverse reactions were observed in 8 out of 16 patients, but almost all were mild. Breast pain, gynecomastia and hot flushes were observed in 6 patients. Adverse reactions regarding liver function tests were observed in 3 patients. These were increased glutamic-oxalacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), alkaliphosphatase (AL-P) or gamma guanosine 5'-triphosphate (gamma-GTP). However, during or after the treatment period the elevated values were reversed to the pretreatment level. ...

/HUMAN EXPOSURE STUDIES/ Long-term clinical trials have been conducted with dosages up to 200 mg of /bicalutamide/ daily and these dosages have been well tolerated. A single dose of /bicalutamide/ that results in symptoms of an overdose considered to be life-threatening has not been established.

/HUMAN EXPOSURE STUDIES/ Severe liver injury, in some cases leading to hospitalization and/or death, has been reported rarely in association with bicalutamide therapy. Hepatotoxicity generally occurred within the first 3-4 months of bicalutamide therapy. Hepatitis or marked increases in serum concentrations of hepatic transaminases leading to discontinuance of bicalutamide therapy were reported in 1% of patients receiving the drug in controlled clinical trials.

/CASE REPORTS/ ... /Investigators/ describe a 59-year-old man with metastatic prostate carcinoma treated with bicalutamide as part of androgen deprivation therapy before starting chemotherapy. At baseline, his liver function test results and serum creatinine concentration were within normal limits, and an abdominal computed tomographic scan did not demonstrate liver metastasis. After 4 days of bicalutamide therapy, the patient came to the emergency department with complaints of abdominal pain, distension, and tenderness. His liver function tests were abnormal, and bicalutamide was discontinued. After 2 days of increasing liver function tests and symptoms of hepatotoxicity, the patient developed tachycardia and hypotension that was resistant to fluid resuscitation. Multiorgan damage was manifested by an alanine aminotransferase level greater than 40 times the upper limit of normal, serum creatinine concentration of 4.2 mg/dL, and troponin I level of 18 ng/mL. The patient died 8 days after bicalutamide therapy was begun secondary to multiorgan failure, most likely as a result of fulminant hepatotoxicity. The Naranjo adverse drug reaction probability scale showed a probable (score of 5) causal relationship between bicalutamide and fulminant hepatotoxicity. Fulminant hepatotoxicity is a rare but potentially fatal adverse effect of bicalutamide. Liver function tests should be monitored before and during bicalutamide therapy, even for patients who have previously completed a course of this therapy with no signs or symptoms of toxicity.

For more Human Toxicity Excerpts (Complete) data for BICALUTAMIDE (6 total), please visit the HSDB record page.

Drug Induced Liver Injury Rank (DILIrank 2.0)

Bicalutamide

vMost-DILI-concern

8

Warnings & precautions

DOI:10.1016/j.drudis.2016.02.015

/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ A small increase in the incidence of hepatocellular carcinoma in male mice given 75 mg/kg/day of bicalutamide and an increased incidence of benign thyroid follicular cell adenomas in rats given 5 mg/kg/day and above were recorded. These neoplastic changes were progressions of non-neoplastic changes related to hepatic enzyme induction observed in animal toxicity studies. Enzyme induction has not been observed following bicalutamide administration in man.

/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ Two-year oral carcinogenicity studies were conducted in both male and female rats and mice at doses of 5, 15 or 75 mg/kg/day of bicalutamide. A variety of tumor target organ effects were identified and were attributed to the antiandrogenicity of bicalutamide, namely, testicular benign interstitial (Leydig) cell tumors in male rats at all dose levels and uterine adenocarcinoma in female rats at 75 mg/kg/day. There is no evidence of Leydig cell hyperplasia in patients; uterine tumors are not relevant to the indicated patient population.

/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ No effects on female rats dosed at 10, 50 and 250 mg/kg/day or their female offspring were observed. Administration of bicalutamide to pregnant females resulted in feminization of the male offspring leading to hypospadias at all dose levels. Affected male offspring were also impotent.

/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ In male rats dosed at 250 mg/kg/day, the precoital interval and time to successful mating were increased in the first pairing but no effects on fertility following successful mating were seen. These effects were reversed by 7 weeks after the end of an 11-week period of dosing.

/GENOTOXICITY/ A comprehensive battery of both in vitro and in vivo genotoxicity tests (yeast gene conversion, Ames, E. coli, CHO/HGPRT, human lymphocyte cytogenetic, mouse micronucleus, and rat bone marrow cytogenetic tests) has demonstrated that /bicalutamide/ does not have genotoxic activity.

Maintain an open airway and assist ventilation if necessary. Treat coma, seizures, hypotension, and arrhythmias if they occur. Treat nausea and vomiting with metoclopramide and fluid loss caused by gastroenteritis with intravenous crystalloid fluids. Bone marrow depression should be treated with the assistance of an experienced hematologist or oncologist. Extravasation: Immediately stop the infusion and withdraw as much fluid as possible by negative pressure on the syringe. ... /For/ decontamination administer activated charcoal orally if conditions are appropriate. Gastric lavage is not necessary after small to moderate ingestions if activated charcoal can be given promptly. Because of the rapid intracellular incorporation of these agents, dialysis and other extracorporeal removal procedures are generally not effective.

Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on the left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Poisons A and B/

Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poisons A and B/

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poisons A and B/

The Approved Drug Products with Therapeutic Equivalence Evaluations List identifies currently marketed prescription drug products, incl bicalutamide, approved on the basis of safety and effectiveness by FDA under sections 505 of the Federal Food, Drug, and Cosmetic Act.

L02BB03

L - Antineoplastic and immunomodulating agents

QL - Antineoplastic and immunomodulating agents

L02BB03

Bicalutamide is an antineoplastic hormonal agent primarily used in the treatment of prostate cancer. Bicalutamide is a pure, nonsteroidal anti-androgen with affinity for androgen receptors (but not for progestogen, estrogen, or glucocorticoid receptors). Consequently, Bicalutamide blocks the action of androgens of adrenal and testicular origin which stimulate the growth of normal and malignant prostatic tissue. Prostate cancer is mostly androgen-dependent and can be treated with surgical or chemical castration. To date, antiandrogen monotherapy has not consistently been shown to be equivalent to castration.

Bicalutamide competes with androgen for the binding of androgen receptors, consequently blocking the action of androgens of adrenal and testicular origin which stimulate the growth of normal and malignant prostatic tissue.

Bicalutamide is a nonsteroidal antiandrogen that is structurally and pharmacologically related to flutamide and nilutamide. Bicalutamide inhibits the action of androgens by competitively blocking nuclear androgen receptors in target tissues such as the prostate, seminal vesicles, and adrenal cortex; blockade of androgen receptors in the hormone-sensitive tumor cells may result in growth arrest or transient tumor regression through inhibition of androgen-dependent DNA and protein synthesis. Bicalutamide is a selective antiandrogen with no androgenic or progestational activity in various animal models. The relative binding affinity of bicalutamide at the androgen receptor is more than that of nilutamide and approximately 4 times that of hydroxyflutamide, the active metabolite of flutamide.

Common pharmacologic therapies for prostate cancer (ie, gonadotropin-releasing hormone [GnRH] analogs, nonsteroidal antiandrogens) when used as monotherapy initially result in increased serum testosterone concentrations, which may limit the effects of the drugs. Androgen receptors in the hypothalamus are blocked by bicalutamide, which disrupts the inhibitory feedback of testosterone on luteinizing hormone (LH) release, resulting in a temporary increase in secretion of LH; the increase in LH stimulates an increase in the production of testosterone. As GnRH analogs have potent GnRH agonist properties, testicular steroidogenesis continues during the first few weeks after initiating therapy. However, the combination of orchiectomy or GnRH analog therapy to suppress testicular androgen production and an antiandrogen to block response of remaining adrenal androgens provides maximal androgen blockade. Concomitant administration of antiandrogens such as bicalutamide in patients initiating therapy with a GnRH analog can inhibit initial androgenic stimulation and potential exacerbation of symptoms (e.g., bone pain, urinary obstruction, liver pain, impending spinal cord compression) that may occur during the first month of GnRH analog therapy.

Bicalutamide was developed from a series of nonsteroidal compounds related to flutamide that showed a range of pharmacologic activity from full androgen agonist to pure antiandrogen, including progestational and antiprogestational properties. Bicalutamide is a pure antiandrogen that binds to rat, dog, and human prostate; the affinity compared with the natural ligand 5 alpha-dihydrotestosterone is low, but bicalutamide has an affinity for the rat androgen receptor approximately four times higher than hydroxyflutamide, the active metabolite of flutamide. Bicalutamide also binds to androgen receptors found in the LNCaP human prostate tumor and the Shionogi S115 mouse mammary tumor cell line, as well as androgen receptors transfected into CV-1 and HeLa cells. In all cases, bicalutamide behaves as a pure antiandrogen and inhibits gene expression and cell growth stimulated by androgen. Studies with the LNCaP cell line are particularly interesting, as these cells contain a mutated androgen receptor (codon 868, Thr-->Ala), which behaves idiosyncratically with other antiandrogens (cyproterone acetate and flutamide): both these antiandrogens act as agonists in this cell line and stimulate proliferation. Studies in vivo show that bicalutamide is a potent antiandrogen in the rat. In immature, castrated male rats treated daily with testosterone propionate, bicalutamide produces a profound inhibition of accessory sex organ (ventral prostate and seminal vesicles) growth at oral doses as low as 0.25 mg/kg; it is more active in this test than flutamide or cyproterone acetate. In mature male rats, daily oral doses of bicalutamide produce a dose-related reduction in weights of the ventral prostate glands and seminal vesicles: in this test, bicalutamide is around five times as potent as flutamide. In contrast to flutamide, which produces dose-related, marked increases in serum luteinizing hormone (LH) and testosterone as a consequence of the central inhibition of the negative feedback effects of androgens on the hypothalamic-pituitary-tests axis, bicalutamide has little effect on serum LH and testosterone; i.e., it is peripherally selective. The peripheral selectivity of bicalutamide in the rat is not due to differences between the prostate versus hypothalamic or pituitary receptors, as bicalutamide reverses the suppressive effect of testosterone on luteinizing hormone-releasing hormone (LHRH) secretion from hypothalamic slices in vitro and is as effective as flutamide at sensitizing the pituitary gland to secrete LH in response to administered LHRH. The peripheral selectivity of bicalutamide has now been shown to be due to poor penetration across the blood-brain barrier: tissue distribution studies with [3H]bicalutamide show that although it is concentrated in the organs of metabolism and secretion as well as in the prostate, the pituitary glands, and the seminal vesicles, levels in the hypothalamus and the central nervous system (CNS) are much lower than in blood. Indeed, it is probable that levels found in the CNS reflect levels of blood contamination. In dogs, bicalutamide has exquisite potency and causes dose-related atrophy of the prostate gland and epididymides; with an oral ED50 of 0.1 mg/kg, it is around 50 times as potent as flutamide in this species and also more potent than the steroidal antiandrogen WIN49596 and the 5 alpha-reductase inhibitor MK-906. Even at substantial multiples of the active dose (up to 100 mg/kg orally), bicalutamide failed to increase serum testosterone, so it is also peripherally selective in the dog.

Although widely accepted as an androgen receptor antagonist, the mechanism by which it induces apoptosis remains unclear. Defining exact pathways by which bicalutamide induces its apoptotic effects would help to advance its clinical applications. /Investigators/ aimed to examine the apoptotic effects of bicalutamide at 24 hr and comment on the role of the caspases and calpains in mediating bicalutamide-induced apoptosis in androgen-dependent and androgen-independent cells. PWR-1E, PC-3 and DU-145 cells were treated with bicalutamide and assessed for apoptosis by flow cytometry at 24 hr. DU-145 cells were used to compare differences between two different metastatic receptor-negative cells and to verify apoptotic induction at 48 hr. To delineate a specific pathway of action for bicalutamide, PC-3 and PWR-1E cells were pretreated with specific inhibitors of caspase-dependent (zVAD-FMK) and caspase-independent pathways (calpain 2 inhibitor). Bicalutamide induced apoptosis in androgen-dependent PWR-1E cells via a caspase-dependent and calpain-independent mechanism. In androgen-independent PC-3 cells, bicalutamide also induced apoptosis by mechanisms that were partially inhibited by pan-caspase inhibition but were partially calpain dependent. Understanding into how bicalutamide exerts its effects in androgen-independent cells will yield further insights into the treatment of hormone-refractory disease.

5.9 days

... Elimination of (S)-bicalutamide was biphasic in some volunteers but monophasic in others (terminal t1/2 =1.2 d; n = 11). ...

/The/ apparent plasma elimination half-life observed following repeated administration was 8.4 +/- 1.1 days.

Bicalutamide undergoes stereo specific metabolism. The S (inactive) isomer is metabolized primarily by glucuronidation. The R (active) isomer also undergoes glucuronidation but is predominantly oxidized to an inactive metabolite followed by glucuronidation.

Bicalutamide undergoes stereospecific metabolism. The S (inactive) isomer is metabolized primarily by glucuronidation. The R (active) isomer also undergoes glucuronidation but is predominantly oxidized to an inactive metabolite followed by glucuronidation. Both the parent and metabolite glucuronides are eliminated in the urine and feces. The S-enantiomer is rapidly cleared relative to the R-enantiomer, with the R-enantiomer accounting for about 99% of total steady-state plasma levels.

Bicalutamide undergoes stereo specific metabolism. The S (inactive) isomer is metabolized primarily by glucuronidation. The R (active) isomer also undergoes glucuronidation but is predominantly oxidized to an inactive metabolite followed by glucuronidation. Half Life: 5.9 days

A0Z3NAU9DP

BICALUTAMIDE

Mechanisms of Action [MoA] - Androgen Receptor Antagonists

Established Pharmacologic Class [EPC] - Androgen Receptor Inhibitor

Bicalutamide is an Androgen Receptor Inhibitor. The mechanism of action of bicalutamide is as an Androgen Receptor Antagonist.

BICALUTAMIDE

Compounds which inhibit or antagonize the biosynthesis or actions of androgens.

Substances that inhibit or prevent the proliferation of NEOPLASMS.

Bicalutamide is well-absorbed following oral administration, although the absolute bioavailability is unknown.

Apparent oral cl=0.32 L/h [Normal Males]

Bicalutamide is well-absorbed following oral administration, although the absolute bioavailability is unknown. Co-administration of bicalutamide with food has no clinically significant effect on rate or extent of absorption.

Bicalutamide is highly protein-bound (96%).

... Bicalutamide metabolites are excreted almost equally in urine and feces with little or no unchanged drug excreted in urine; conversely, unchanged drug predominates in plasma. Bicalutamide in feces is thought to arise from hydrolysis of bicalutamide glucuronide and from unabsorbed drug. ...

... Healthy male volunteers (n = 15) were administered single oral doses of bicalutamide (50 mg) after food and after fasting as part of a three-treatment, three-period, randomized cross-over study, with a 9 week washout. After fasting, plasma concentrations of (R)-bicalutamide were much higher than those of (S)-bicalutamide; the mean (R)-enantiomer Cmax (734 ng mL-1) was about nine times higher than the (S)-enantiomer value (84 ng mL-1). The corresponding tmax values were 19 and 3 hr for (R)- and (S)-bicalutamide, respectively. Elimination of (R)-bicalutamide from plasma was monoexponential and slow (t1/2 = 5.8 d). Elimination of (S)-bicalutamide was biphasic in some volunteers but monophasic in others (terminal t1/2 =1.2 d; n = 11). There was no significant effect of food on AUC, tmax, or t1/2 data for either enantiomer. The observed slightly higher values of Cmax for (R)-bicalutamide (14%) and (S)-bicalutamide (19%), when dosing with food, achieved statistical significance. ...

in treatment of prostrate cancer

... nonsteroidal anti-androgen with affinity for androgen receptors ... blocks the action of androgens of adrenal and testicular origin with stimulate the growth of normal and malignant prostatic issue

THERAP CAT: Antiandrogen; antineoplastic (hormonal)

Use (kg; approx.) in Germany (2009): >750

For treatment (together with surgery or LHRH analogue) of advanced prostatic cancer.