Finasteride works by preventing the
action of a chemical called 5-alpha reductase.
In the body, the hormone testosterone is converted to a more
active form, dihydrotestosterone (DHT), by 5-alpha reductase. Finasteride
blocks the action of 5-alpha reductase, and therefore prevents the activation
of testosterone.
The enlargement of the prostate gland, which often occurs in men
with advancing age (benign prostatic hyperplasia), is dependant upon
testosterone being converted to DHT within the prostate gland. In the absence
of DHT the prostate shrinks. Therefore, by decreasing the amount of DHT,
finasteride helps shrink the prostate.
The prostate gland is found only in men and lies at the top of
the tube connecting the bladder to the outside (urethra). Enlargement of the
prostate causes it to press on the urethra and bladder and can cause urinary
symptoms such as poor flow of urine. By shrinking the prostate, finasteride
relieves the pressure on the bladder and urethra. This allows urine to flow
freely past the prostate and relieves the urinary symptoms.
Women who are pregnant or of childbearing age should not handle
broken or crushed tablets of this medicine, as the medicine may be absorbed
through the skin and be harmful to an unborn child.
While you are taking this medicine you should use a condom
during sex if your sexual partner is pregnant or could become pregnant. This is
because the active ingredient of this medicine passes into semen, and could
harm the development of an unborn child.
This medicine does not cause
prostate cancer, but prostate cancer can be another
cause of an enlarged prostate gland. For this reason, tests for prostate cancer
should be carried out before you start treatment with this medicine, and at
regular intervals thereafter.
Use with caution in
Men with very poor flow of urine or obstruction of the urinary
tract (urethra).
Not to be used in
Women.
Children.
Rare hereditary problems of galactose intolerance, the Lapp
lactase deficiency or glucose-galactose malabsorption (Proscar tablets contain
lactose).
This medicine should not be used if you are allergic to one or
any of its ingredients. Please inform your doctor or pharmacist if you have
previously experienced such an
allergy.
If you feel you have
experienced an allergic reaction, stop using this medicine and inform your
doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or
breastfeeding. However, other medicines may be safely used in pregnancy or
breastfeeding providing the benefits to the mother outweigh the risks to the
unborn baby. Always inform your doctor if you are pregnant or planning a
pregnancy, before using any medicine.
This medicine is for use by men only, therefore information
about its use by pregnant or breastfeeding women is not applicable. However,
this medicine may pass into semen, and for this reason men whose partner is or
may be pregnant should use a barrier form of contraception such as a condom
during sex, to avoid any possible risks to a developing foetus.
Side effects
Medicines and their possible side effects can affect individual
people in different ways. The following are some of the side effects that are
known to be associated with this medicine. Just because a side effect is stated
here does not mean that all people using this medicine will experience that or
any side effect.
Impotence.
Allergy to active ingredients (hypersensitivity).
Rash (allergic reaction).
Breast tenderness/swelling.
Ejaculation disorders.
Decreased sex drive.
The side effects listed above may not include all of the side
effects reported by the drug's
manufacturer.
For more
information about any other possible risks associated with this medicine,
please read the information provided with the medicine or consult your doctor
or pharmacist.
How can this medicine affect other medicines?
This medicine is not known to significantly affect other
medicines.
