Alprostadil injection, and why it works when a tablet does not

An alprostadil injection works in men for whom tablets do nothing, and it works for a reason worth understanding before deciding against it. A PDE5 inhibitor only amplifies a signal the nerves have already sent; alprostadil is that signal. Injected into the corpus cavernosum it relaxes smooth muscle directly, which means it produces an erection after prostate surgery, after nerve injury, and in long-standing diabetes — the three situations where sildenafil and tadalafil most often fail. Response rates in those groups run far above anything oral treatment achieves.

What the first dose is for

The first injection is always given in a clinic, and not out of caution about needles. It is a dose-finding exercise: the starting dose is 2.5 micrograms, raised in small steps on separate visits until an erection firm enough for penetration lasts no more than about an hour. Most men settle between 5 and 20 micrograms; men with neurogenic causes often need less than men with vascular disease.

Getting that number right is what prevents the complication everyone has heard about. An erection beyond four hours is priapism, it damages tissue, and it is an emergency department visit rather than something to wait out. Titration under supervision is how the risk is kept at the fraction of a per cent it actually is, and it is the reason this is not a product to self-start from a box.

Injecting it without getting it wrong

The injection goes into the side of the shaft, at the three or nine o'clock position, in the middle third. Never into the underside, where the urethra runs, and never into the top, where the dorsal vessels and nerves sit. Alternate sides between doses. Press for five minutes afterwards if you take any anticoagulant, and longer if bruising has been a problem before.

Frequency is capped at three times a week and once in any twenty-four hours. The erection begins within five to twenty minutes and does not need arousal to appear, which is the one feature men find strangest about it compared with a tablet.

Prices by strength and pack

Indicative prices in US dollars. Single vials are for the titration phase; once a dose is established, the larger packs are what brings the cost per occasion down.

What it costs in side effects

Penile pain during or after the injection is the commonest, reported by a substantial minority, and it is caused by the drug rather than the needle — alprostadil is a prostaglandin, and prostaglandins hurt. It tends to lessen with use. Bruising at the site is frequent and avoidable with technique.

The complication that decides long-term use is fibrosis: small areas of scarring in the corpora after months or years of injections, which can produce curvature. Rotating the site and keeping to the frequency limit are the only real protections, and a man who notices a developing bend should be examined rather than reassured. Men with sickle cell disease, multiple myeloma, leukaemia or an existing penile implant should not use it at all, and the same goes for anyone with a condition predisposing to priapism.

Where it sits against the alternatives

Oral treatment is first line because it is easier, not because it is stronger. If sildenafil at 100 mg has failed on several properly timed attempts — on an empty stomach, with adequate stimulation, four or more occasions — and tadalafil has failed too, the useful question is not which tablet to try next. It is whether the nerve signal is arriving at all. Alprostadil answers that question in twenty minutes.

There is also a diagnostic use to the response. An erection that appears normally with an injection but never appears spontaneously points at nerves or arousal rather than at plumbing, and arousal that is absent with a partner but intact alone points somewhere else again. That distinction is the one clinical sexology exists to work on, and at this studio the first consultation is free. The oral range is listed under men's health; where low desire rather than erection is the complaint, testosterone undecanoate and the hormonal work-up come first.

Questions people actually ask

Does it hurt?

The needle is fine and short; the ache afterwards is the part men notice, and it comes from the drug. It affects a minority, usually fades with repeated use, and is the main reason some men move to an implant instead.

Can I combine it with a tablet?

Not without supervision. Stacking a PDE5 inhibitor on an injection raises the priapism risk substantially, and that combination is something a urologist decides on, not something to try at home.

Will it work if nothing else has?

Usually, yes — that is the point of it. The exception is severe arterial disease with no inflow to work with, and venous leak, where the erection appears and then drains away within minutes.

How long can I keep using it?

Years, in practice. What limits it is pain, fibrosis or simply the willingness to inject, and all three are worth reviewing annually rather than drifting on.

The label these figures come from

Dose titration, injection technique, frequency limits and contraindications follow the FDA prescribing information for alprostadil for intracavernosal injection, and the place of intracavernosal therapy after failed oral treatment follows the European Association of Urology guidance on sexual and reproductive health. This page is information; the first dose belongs in a clinic.