Dutasteride

Why there is no syringe

There is no syringe. Dutasteride is supplied as a 0.5 mg soft gelatin capsule with a liquid fill, and the label is unusually firm about not interfering with it: “The capsules should be swallowed whole and not chewed or opened, as contact with the capsule contents may result in irritation of the oropharyngeal mucosa.” That instruction has a second edge the record has to carry, because it is the whole reason the capsule shell matters — section 16 of the same label states that “Dutasteride is absorbed through the skin” and that the capsules “should not be handled by women who are pregnant or who could become pregnant”. Opening a capsule to split or dilute the liquid removes the only barrier the label describes.

Administration

1. 1

   Start by reading the indication, because it is not hair loss

   AVODART’s section 1 is unambiguous: it is “indicated 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, and reduce the risk of BPH-related surgery. There is no androgenetic alopecia indication on the US label, and section 1.3 adds a limitation of use: “AVODART is not approved for the prevention of prostate cancer.” Dutasteride for hair loss in the United States is off-label prescribing.

2. 2

   Swallow the capsule whole

   “The capsules should be swallowed whole and not chewed or opened, as contact with the capsule contents may result in irritation of the oropharyngeal mucosa. AVODART may be administered with or without food” (section 2). Food reduces peak concentration by 10% to 15%, which the label calls of no clinical significance.

3. 3

   Keep the capsules away from anyone who is or may become pregnant

   Section 5.4 is headed “Transdermal Exposure of AVODART in Pregnant Women—Risk to Male Fetus”: “AVODART capsules should not be handled by women who are pregnant or may be pregnant. Dutasteride can be absorbed through the skin and could result in unintended fetal exposure and potential risk to a male fetus. If a pregnant woman comes in contact with leaking dutasteride capsules, the contact area should be washed immediately with soap and water.” Pregnancy is a contraindication on this label, not a precaution.

4. 4

   Do not donate blood while taking it, or for six months after

   Section 5.5 states: “Men being treated with AVODART 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.” Six months rather than a few days is a consequence of the half-life below.

5. 5

   Understand that stopping does not clear it quickly

   Section 12.3: “The terminal elimination half-life of dutasteride is approximately 5 weeks at steady state.” It also states that serum concentrations remain detectable for up to 4 to 6 months after stopping, and that the half-life rises with age — roughly 170 hours in men aged 20 to 49, 260 hours at 50 to 69 and 300 hours over 70. Finasteride’s is hours; dutasteride’s is weeks, and that difference governs both the blood-donation deferral and how long any adverse effect takes to wash out.

6. 6

   Re-baseline your PSA

   Section 5.1: “In clinical trials, AVODART reduced serum PSA concentration by approximately 50% within 3 to 6 months of treatment.” The label instructs that a new PSA baseline be established at least 3 months after starting and monitored thereafter, and that “to interpret an isolated PSA value in a man treated with AVODART for 3 months or more, the PSA value should be doubled for comparison with normal values in untreated men.”

Storage

• —Store at 25 °C (77 °F); excursions permitted to 15–30 °C (59–86 °F) [see USP Controlled Room Temperature] — quoted from section 16 of the AVODART label.
• —Keep the capsules in their child-resistant bottle. The label directs that they not be handled at all by women who are pregnant or could become pregnant.
• —Discard any capsule that is leaking rather than wiping it — the label’s instruction for skin contact with leaked contents is to wash the area immediately with soap and water.

Monitoring

Frequently asked questions

Is dutasteride FDA-approved for hair loss?

Not in the United States. AVODART (NDA 021319) is approved for symptomatic benign prostatic hyperplasia in men with an enlarged prostate, and the combination product JALYN pairs it with tamsulosin for the same condition. There is no androgenetic alopecia indication on any US dutasteride label, so prescribing it for hair loss is off-label — which is legal for a physician to do and does not mean the FDA has evaluated it for that use. Finasteride, by contrast, has a labelled hair-loss product at 1 mg.

What dose does the label state?

One 0.5 mg capsule once daily, swallowed whole: “The recommended dose of AVODART is 1 capsule (0.5 mg) taken once daily.” With tamsulosin it is the same 0.5 mg alongside tamsulosin 0.4 mg once daily. Both are BPH regimens. The label states no hair-loss dose at all, and this page does not supply one from anywhere else.

How long does dutasteride stay in the body after stopping?

Far longer than finasteride. The label states a terminal elimination half-life of approximately 5 weeks at steady state, with serum concentrations still detectable above 0.1 ng/mL for up to 4 to 6 months after discontinuation, and a half-life that lengthens with age — around 170 hours in men aged 20 to 49 rising to about 300 hours over 70. That is why the blood-donation deferral is six months, and it is the practical difference a man should weigh before starting: an unwanted effect does not stop when the capsule does.

Why does the label say not to donate blood?

To keep the drug out of a pregnant transfusion recipient. Section 5.5 states: “Men being treated with AVODART 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.” Dutasteride use is contraindicated in pregnancy because it inhibited development of male fetal external genitalia in animal reproduction studies.

Can the capsule be opened or split to make a smaller dose?

The label says no, for two separate reasons, and this page will not describe how. “The capsules should be swallowed whole and not chewed or opened, as contact with the capsule contents may result in irritation of the oropharyngeal mucosa,” and section 16 states plainly that “Dutasteride is absorbed through the skin.” The shell is the barrier. Opening it puts a liquid absorbed through skin onto the hands of whoever is holding it.

Sources

1. [1]FDA label — AVODART (dutasteride) soft gelatin capsules, Waylis Therapeutics LLC (DailyMed SPL 960797b3-09b1-4d6a-8ece-8b5d918e93e4; Drugs@FDA NDA 021319, initial US approval 2001). Source of the BPH-only indication, the 0.5 mg once-daily dose, the swallow-whole instruction, the transdermal exposure warning, the blood donation deferral, the 5-week half-life and the PSA statements
2. [2]Drugs@FDA: FDA-Approved Drugs — the approval record, used to confirm that NDA 021319 carries a benign prostatic hyperplasia indication and that no US dutasteride application carries an androgenetic alopecia indication
3. [3]DailyMed — the full set of current dutasteride Structured Product Labels (34 as of 2026-09-19: AVODART, generic dutasteride capsules, and dutasteride/tamsulosin combinations). Every one of them is indicated for benign prostatic hyperplasia; none carries a hair-loss indication

Related

• Finasteride — the labelled hair-loss 5-ARI
• Minoxidil — approved, over the counter
• Norwood scale — stage your hair loss
• Compare online hair loss providers
• Hair restoration: what the evidence supports