What is Dutasteride (Avodart / Avolve)?
Dutasteride is the active compound in a new oral medicine made
by GlaxoSmithKline, which has proved very effective in treating
genetic male pattern hair loss on the vertex (top of the head)
and the mid-scalp area.
The medicine has been approved for prescription by the US Food
& Drug Administration, and in Europe.
Why was Dutasteride developed?
Dutasteride was developed for treating symptomatic benign prostatic
hyperplasia (BPH) in men. Dutasteride is chemically similar to
Finasteride, the active compound in Propecia, but has proven more
effective in clinical trials. Like Propecia, Dutasteride has proved
to be effective in treating male pattern hair loss as well as
BPH.
How does Dutasteride work?
Researchers have discovered that men who suffer from either male
pattern hair loss or benign prostatic hyperplasia (BPH), have
increased levels of the hormone dihydrotestosterone (DHT).
DHT is produced from testosterone by an enzyme called 5-alpha-reductase.
Biochemical analysis reveals higher levels of 5-alpha-reductase
in the bloodstream of men with BPH, and in the scalps of men with
hair loss; and less of this enzyme in men with no BPH or no hair
loss.
Dutasteride inhibits 5-alpha-reductase, blocking the formation
of DHT. This interrupts a key trigger element in development of
male pattern hair loss and in development of BPH.
How is Dutasteride different from Propecia?
Both medicines work in a similar way. However, Dutasteride inhibits
the activities of two types of 5-alpha-reductase enzymes. In contrast,
Propecia (Finasteride) only inhibits one type. Dutasteride has
been shown to decrease levels of DHT by 90% after only two weeks,
making it a more powerful and faster-acting weapon against hair
loss and BPH than Finasteride.
What is dihydrotesterone (DHT)?
DHT is one of several male hormones in the body. DHT is responsible
for the development of the external genitals in the male foetus.
However, in adult males DHT appears to cause:
What studies and trials have been done concerning Dutasteride?
GlaxoSmithKline completed Phase II trials for FDA approval of
Dutasteride for treating hair loss. After six month of treatment,
the hair counts measured in a 1 inch diameter circle increased
by an average 96 hairs with 0.5mg Dutasteride, compared to an
average 72 hairs with 5mg Propecia (Finasteride). The drug was
shown to be well tolerated.
Also, a total of 2951 men with moderate to severe BPH were treated
with 0.5 mg Dutasteride daily. The study found that acute urinary
retention was reduced by 57%, and the risk of benign prostatic
hyperplasia-related surgical intervention was cut by 48% compared
with placebo. The drug was shown to be well tolerated.
So these initial trials show that Dutasteride is around 30% more
effective than Propecia in promoting hair regrowth. However, please
note that Dutasteride has only been specifically approved for
treating BPH. It has not yet been approved specifically for treating
hair loss.
When will Dutasteride be approved for treating hair loss?
In November 2002 GlaxoSmithKline cancelled its planned Phase
3 trials for Dutasteride for treating hair loss. The company has
not publicly given a reason for this.
However, industry sources speculate that the reason is commercial
rather than medical: the suggestion is that trials were stopped
because the maker thinks Dutasteride will be perceived as too
similar to Propecia in consumers’ minds, and may not generate
sufficient return on investment to justify the cost of approvals
as a treatment for hair loss.
However, Dutasteride is approved by the US FDA and by European
bodies for the treatment of BPH, and so has passed all relevant
safety standards.
Will Dutasteride help hair re-growth for all men?
As with Propecia, Dutasteride increases the number of scalp hairs,
helping to fill-in thin areas of the scalp. Although results will
vary, generally men will not re-grow all of the hair they have
lost. Male pattern hair loss occurs gradually over time, but Dutasteride
can significantly reduce or delay hair loss.
How should I take Dutasteride?
Dutasteride is supplied as gel-filled capsules with 0.5mg dosage
(GSK’s Avodart). Take dutasteride exactly as directed by your
doctor. If you do not understand these instructions, ask your
pharmacist, nurse, or doctor to explain them to you.
Take each dose with a full glass of water, swallow the capsules
whole. Do not chew, crush or break the capsules. Dutasteride can
be taken with or without food.
What dosage should I take?
You should only take the dose as recommended by your doctor.
Do not change the dose without consulting your doctor.
Effectiveness of Dutasteride has been evaluated at different
daily dosages, ranging from 0.01mg, 0.05mg, 0.5mg, 2.5mg, and
5.0mg per day.
It was found that the highest suppression of DHT was achieved
with 2.5mg or 5.0mg per day. At a daily dosage of 2.5mg or 5.0mg,
Dutasteride suppresses close to 100% of DHT. This compares favourably
with 5.0mg daily dosage of Propecia (Finasteride) which suppresses
only 70% of DHT.
You should note, however, that Dutasteride is very effective
at small doses. At a daily dose of 0.5mg, DHT inhibition is close
to 90%. Also, the level of DHT suppression is not significantly
greater between 2.5mg and 5.0 mg.
Is Dutasteride safe?
Clinical trials showed that it was generally well tolerated.
Most side effects were mild, and generally went away while on
treatment in both the Dutasteride and placebo groups.
Drug-related side effects during the first six months were as
follows:
