Zyfetor Drug Information [ GlaxoSmithKline ]

Table of content

Zyfetor category:

• Human

Active ingredients:

• Dutasteride

Zyfetor companies and manufacturers:

• GlaxoSmithKline

General Information

Zyfetor forms, composition and dosages:

• N / A

Indications, usages and classification codes:

• G04CB02 - Dutasteride

There is an additional general information about this medication active ingredient dutasteride:

Pharmacological action

This medication is a drug for the treatment of benign prostatic hyperplasia. It inhibits the activity of isoenzymes of 5a-reductase type 1 and 2 are responsible for the conversion of testosterone to 5a-dihydrotestosterone. DHT is the primary androgen responsible for hyperplasia of the glandular tissue of the prostate gland.
The maximum effect of dutasteride on the reduction of the concentration of DHT is dose dependent and is observed in 1-2 weeks after starting treatment. After 1 and 2 weeks receiving dutasteride at a dose of 0.5 mg / day an average concentrations of DHT in serum is reduced by 85% and 90%.
Dutasteride reduces the size of the prostate, improves urination and reduces the risk of acute urinary retention and the need for surgical treatment.

Pharmacokinetics

After a single oral dose 0.5 mg C_max of serum dutasteride achieved within 1-3 hours. When the 2-hours intravenous infusion absolute bioavailability is approximately 60%.
Bioavailability of dutasteride is independent of ingestion.
Plasma protein binding is high - more than 99.5%. V_d is 300-500 L. While using dutasteride in therapeutic doses its final T_1/2 is 3-5 weeks. Dutasteride is found in serum (at concentrations greater than 0.1 ng / ml) up to 4-6 months after the termination of its administration.
There was not significant differences between age groups in the degree of reduction of the levels of DHT. These results indicate that there is no need to reduce the dose of dutasteride in elderly patients.

Why is Zyfetor prescribed?

Treatment of benign prostatic hyperplasia.

Dosage and administration

For adult men including elderly patients the recommended dose for oral administration is 500 mg 1 time / day. Treatment should been continued for at least 6 months.

Zyfetor side effects

Reproductive system: erectile dysfunction, a change (decrease) in libido, impaired ejaculation, gynecomastia (including pain and increased breast).
Allergic reactions: in some cases - a rash, itching, urticaria, localized edema.

Contraindications

Hypersensitivity to dutasteride, and other 5a-reductase inhibitors; contraindicated using for women and children.

Special instructions

Dutasteride should be used with caution in patients with impaired liver function, because it is subjected to intensive metabolism in the liver and its T_1/2 is 3-5 weeks.
There is needed a digital rectal examination for patients with benign prostatic hyperplasia and other methods of prostate cancer before treatment with dutasteride and periodically repeating these studies in the treatment process to prevent the development of prostate cancer.
Determination of the concentration of PSA in serum is an important component of the complex studies aimed at identifying prostate cancer. Initial PSA level less than 4 ng / ml in patients receiving dutasteride does not exclude the diagnosis of prostate cancer.
Dutasteride is absorbed through the skin, thats why women and children should avoid a contact with this active substance. In the case of such contact it is necessary to rinse the appropriate area of skin with soap and water.

Zyfetor drug interactions

Because dutasteride is metabolized by isoenzyme CYP3A4 in the presence of CYP3A4 inhibitors dutasteride concentration in the blood can increases.
Simultaneous administration of dutasteride with CYP3A4 inhibitors verapamil and diltiazem causes a decrease in clearance. However, an another calcium channel blocker amlodipine does not reduce the clearance of dutasteride.

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