Alfusin D

Uses

Alfuzosin Hydrochloride is used for the treatment of the signs and symptoms of benign prostatic hyperplasia(BPH), lower urinary tract symptoms (LUTS) including urinary frequency, nocturia, incomplete emptying and urinary hesitancy associated with BPH.

Dutasteride is used for the treatment of symptomatic benign prostatic hyperplasia (BPH) in men with an enlarged prostate to:

• Improve symptoms
• Reduce the risk of acute urinary retention
• Reduce the risk of the need for BPH-related surgery

Alfusin D is also used to associated treatment for these conditions: Benign Prostatic Hyperplasia (BPH)Benign Prostatic Hyperplasia (BPH), Symptomatic Benign Prostatic Hyperplasia

How Alfusin D works

Alpha(1)-adrenoreceptors are found in the prostate, bladder base, bladder neck, prostatic capsule, and prostatic urethra; their activation may lead to contraction of smooth muscle and urinary symptoms in patients with BPH. Alfuzosin selectively binds to and inhibits alpha(1)-adrenergic receptors in the lower urinary tract. This leads to the relaxation of smooth muscle in both the prostate and bladder neck, resulting in the improvement in urine flow and a reduction of urinary symptoms.

The 5α-reductase is a nuclear-bound steroid intracellular enzyme primarily located in the prostatic stromal cell that converts the androgen testosterone into the more active metabolite, 5α-dihydrotestosterone (DHT). DHT is considered to be the primary androgen playing a role in the initial development and subsequent enlargement of the prostate gland. It serves as the hormonal mediator for the hyperplasia upon accumulation within the prostate gland. DHT displays a higher affinity towards androgen receptors in the prostate gland compared to testosterone and by acting on the androgen receptors, DHT modulates genes that are responsible for cell proliferation. Responsible for the synthesis of approximately one-third of circulating DHT, type I 5α-reductase is predominant in the sebaceous glands of most regions of skin, including the scalp, and liver. The type II 5a-reductase isozyme is primarily found in the prostate, seminal vesicles, epididymides, and hair follicles as well as liver, and is responsible for two-thirds of circulating DHT. Due to its dual inhibition of both isoenzymes of 5α-reductase, dutasteride causes a near-complete suppression of DHT. Compared to a 70% reduction of serum DHT levels caused by finasteride, a near-complete suppression of serum DHT-more than 90% is seen with dutasteride.

By forming a stable complex with both type II and type II 5α-reductase, dutasteride inhibits its enzymatic action of converting testosterone to 5α-dihydrotestosterone (DHT), which is the androgen primarily responsible for the initial development and subsequent enlargement of the prostate gland. It is proposed that DHT is the principal androgen responsible for prostatic growth in later life-normal masculinization of the external genitalia and maturation of the prostate gland during development-thus reducing the serum DHT levels results in reduced prostatic volume and increased epithelial apoptosis. Dutasteride is a competitive and specific inhibitor of both Type I and Type II 5α-reductase isoenzymes and when evaluated under in vitro and in vivo conditions, the dissociation of the drug from the drug-enzyme complex is reported to be extremely slow. Dutasteride does not bind to the human androgen receptor.

Dosage

Alfusin D dosage

The recommended dosage is one 10 mg Alfuzosin Hydrochloride tablet daily to be taken immediately after the same meal each day. The tablets should not be chewed or crushed.

The recommended dose is Dutasteride 0.5 mgorally once daily. The capsules should be swallowed whole. Dutasteride may be administered with or without food.

Alfuzosin Hydrochloride tablet should be swallowed whole.

Side Effects

This formulation is generally well tolerated. However the following adverse events have been reported include abdominal pain, dyspepsia, constipation, nausea, impotence, bronchitis, sinusitis and pharyngitis.

• Sexual problems (such as decreased sexual interest/ ability, decrease in the amount of semen/ sperm released during sex)
• Impotence (trouble getting or keeping an erection)
• Testicle pain or swelling
• Increased breast size
• Breast tenderness.

Toxicity

The oral LD50 of alfuzosin is 2300 mg/kg in male mice and 1950 mg/kg in female mice. An overdose of alfuzosin can cause hypotension. Cardiovascular support should be initiated immediately. The patient should be kept in the supine position to aid in restoring pressure and managing heart rate. Fluid resuscitation should also be considered in severe cases; sometimes, vasopressors are required. Renal function should be monitored frequently. Dialysis may not be of benefit to alfuzosin protein binding of up to 90%.

LD50 values

The estimated dermal LD50 of dutasteride in rabbits is > 2,000 mg/kg.

Overdose

In studies of volunteers receiving single doses of dutasteride up to 40 mg (which is 80 times the therapeutic dose) for 7 days, there were no reports of clinically significant adverse events. Low incidences of impotence, reduced libido, gynecomastia, and ejaculation disorder occurred significantly more often in dutasteride than placebo recipients. There are no known antidotes for dutasteride. In case of overdose, appropriate symptomatic and supportive treatment should be given.

Nonclinical Toxicology

In a 2-year carcinogenicity mouse study, there was an increased incidence of benign hepatocellular adenomas in female mice receiving 250 mg/kg/day. An increased incidence of Leydig cell hyperplasia was observed in male rats receiving doses of 7.5 mg/kg/day and greater. At tumorogenic doses, the luteinizing hormone (LH) levels in rats were increased by 167%. There was no demonstrated a genotoxic potential of dutasteride or its metabolites in a bacterial mutagenesis assay, a chromosomal aberration assay in CHO cells, and a micronucleus assay in rats. At much higher doses than the maximum recommended human dose (MRHD) in sexually mature male rats, dutasteride caused a dose- and time-dependent decrease in fertility, reduced cauda epididymal (absolute) sperm counts but not sperm concentration (at 50 and 500 mg/kg/day), reduced weights of the epididymis, prostate, and seminal vesicles, and microscopic changes in the male reproductive organs. At exposures 425- and 315-fold the expected clinical exposure of dutasteride in rats and dogs, respectively, there were some signs of non-specific, reversible, centrally-mediated toxicity without associated histopathological changes.

Pregnancy and Lactation

As DHT is a necessary hormone for the development of male genitalia, exposure to dutasteride in pregnant women bearing male fetuses may cause fetal harm. In animal reproduction and developmental toxicity studies, dutasteride inhibited normal development of external genitalia in male fetuses. Although it is not known whether dutasteride is excreted in human milk, the use of dutasteride in women of childbearing potential, including nursing women. In elderly patients, the half-life of dutasteride may increase. As the renal elimination of dutasteride is very minimal, the use of dutasteride in patients renal insufficiency is reported to be safe. There are no specific dosage adjustment recommendations for use in elderly patients or patients with renal impairment.

Precaution

Alfuzosin Hydrochloride should not be given to patients with moderate or severe hepatic insufficiency. Caution should be exercised when Alfuzosin is administered in patients with severe renal insufficiency. If symptoms of angina pectoris should newly appear or worsen, Alfuzosin Hydrochloride should be discontinued.

Lower urinary tract symptoms of BPH can be indicative of other urological diseases, including prostate cancer. Patients should be assessed to rule out other urological diseases prior to treatment with Dutasteride. Patients with a large residual urinary volume and/or severely diminished urinary flow may not be good candidates for 5 a-reductase inhibitor therapy and should be carefully monitored for obstructive uropathy. Blood Donation: Men being treated with Dutasteride should not donate blood until at least 6 months have passed following their last dose. The purpose of this deferred period is to prevent administration of Dutasteride to a pregnant female transfusion recipient.

Interaction

Alfuzosin may interact with other alpha-blockers, Atenolol, Cimetidine, Diltiazem, Ketoconazole and Ritonavir.

Care should be taken when administering Dutasteride to patients taking potent, chronic CYP3A4 inhibitors. Dutasteride does not inhibit the in vitro metabolism of model substrates for the major human cytochrome P450 isoenzymes (CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4) at a concentration of 1,000 ng/ml, 25 times greater than steady-state serum concentrations in humans. In vitro studies demonstrate that Dutasteride does not displace Warfarin, Diazepam, or Phenytoin from plasma protein binding sites, nor do these model compounds displace Dutasteride.

Volume of Distribution

The volume of distribution of alfuzosin after intravenous administration in healthy volunteers is about 3.2 L/kg. Alfuzosin distributes heavily to the tissues of the prostate.

Dutasteride displays a large volume of distribution ranging from 300 to 500 L. Following daily oral administration of 0.5 mg dutasteride healthy subjects for 12 months, the semen dutasteride concentrations averaged 3.4 ng/mL (range: 0.4 to 14 ng/mL) with 11.5% of serum dutasteride concentrations being partitioned into semen.

Elimination Route

Alfuzosin is readily absorbed in the gastrointestinal tract and the absolute bioavailability under fed conditions is 49%. In patients over 75 years of age, alfuzosin is absorbed more rapidly and peak plasma levels are higher. One source mentions a bioavailability of 64%. After multiple doses under fed conditions, Cmax is achieved in 8 hours. Cmax and AUC0-24 values are about 13.6 ng/mL and 194 ng·h/mL, respectively. Steady-state plasma concentrations are achieved after the second dose and are 1.2 to 1.6 times higher than after a single dose. With the extended-release formulation, alfuzosin release is sustained over 20 hours with a rate of dissolution ranging between 2 and 12 hours.

Following oral administration of a single dose of 0.5 mg dutasteride, the peak serum concentrations were reached within 2 to 3 hours. Following daily oral administration of 0.5 mg dutasteride, the steady-state concentration of 40 ng/mL is expected to be achieved at 6 months following initial administration. In healthy subjects, the absolute bioavailability was 60%, ranging from 40% to 94%. While food intake reduced the maximum serum concentrations by 10 to 15%, food intake is reported to have a negligible effect on the bioavailability of the drug.

Half Life

The apparent elimination half-life of alfuzosin after oral administration is about 10 hours. The terminal half-life is 3-5 hours.

The terminal elimination half-life of dutasteride is approximately 5 weeks at steady state. This long half-life accounts for the serum concentrations remaining detectable for up to 4 to 6 months after discontinuation of treatment.

Clearance

Exercise caution if renal clearance is < 30 mL/min. The clearance of alfuzosin is increased in renal insufficiency (with or without dialysis), due to an increase in the free fraction.

In a study of healthy volunteers receiving single oral doses of dutasteride ranging from 0.01 to 40 mg, dutasteride displayed a low linear clearance of 0.58 L/h. The estimated inter-individual variability for the linear clearance was high.

Elimination Route

It is partially metabolised and excreted mainly in the bile and faeces. Following oral administration of a radiolabeled alfuzosin solution, the detection of radioactivity after one week was 69% in the feces and 24% in the urine.

Dutasteride and its metabolites mainly undergo fecal excretion. About 1-15% of the dose is excreted as the unchanged parent compound, while 2-90% of the total dose is excreted in the form of dutasteride-related metabolites in the feces. Trace amounts of unchanged dutasteride, with less than 1%, can also be detected in the urine. Therefore, on average, the dose unaccounted for approximated 55%, with a range between 5% and 97%.

Pregnancy & Breastfeeding use

Alfuzosin Hydrochloride is not indicated for use in pregnant and lactating mother.

Pregnancy Category X. Dutasteride is contraindicated for use in women.

Contraindication

Alfuzosin Hydrochloride tablet is contraindicated for hypersensitivity to Alfuzosin Hydrochloride, history of orthostatic hypotension, combination with other alpha-1 receptor blockers, hepatic insufficiency.

Dutasteride is contra-indicated for use in women and children and for patients with known hypersensitivity to Dutasteride, and other 5 a-reductase inhibitors. Warnings: Exposure of women-risk to male fetus: Dutasteride is absorbed through the skin. Therefore, women who are pregnant or may be pregnant should not handle Dutasteride capsules because of the possibility of absorption of Dutasteride and the potential risk of a fetal anomaly to a male fetus. If contact is made with leaking capsules, the contact area should be washed immediately with soap and water.

Special Warning

Efficacy of Alfuzosin Hydrochloride has not been demonstrated in children aged 2 to 16 years. Therefore Alfuzosin Hydrochloride is not indicated for use in the paediatric population.

Pediatric use: Dutasteride is not indicated for use in the pediatric population. Safety and effectiveness in the pediatric population have not been established.

Geriatric use: No overall differences in safety or efficacy were observed between elderly and adult subjects.

Elderly use: No dosage adjustment is necessary for subjects with renal impairment or for the elderly.

Hepatic impairment: Due to the absence of data in patients with hepatic impairment, no dosage recommendation can be made.

Acute Overdose

Overdose of Alfuzosin Hydrochloride should lead to hypotension; support of the cardiovascular system is of first importance. Restoration of blood pressure and normalization of heart rate may be accomplished by keeping the patient in the supine position. If this measure is inadequate, then the administration of intravenous fluids should be considered. If necessary, vasopressors should then be used, and the renal function should be monitored and supported as needed.

In volunteer studies, single doses of Dutasteride up to 40 mg (80 times the therapeutic dose) for 7 days have been administered without significant safety concerns. In a clinical study, daily doses of 5 mg (10 times the therapeutic dose) were administered to 60 subjects for 6 months with no additional adverse effects to those seen at therapeutic doses of 0.5 mg. There is no specific antidote for Dutasteride. Therefore, in cases of suspected overdosage symptomatic and supportive treatment should be given as appropriate, taking the long half-life of Dutasteride into consideration.

Storage Condition

Store in a cool and dry place, protected from light

Store in a cool and dry place, protected from light

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