Trimix intracavernosal injection

Our assessment

Start with the number, because it reframes everything else on this site. One injection costs between about a dollar forty and three dollars thirty. A compounded sublingual works out around twenty-three dollars a use. A branded tablet is more. This is the cheapest effective dose we have found anywhere, by a wide margin.

It is also the most effective. Intracavernosal injection produces an erection adequate for intercourse in the large majority of men who use it — higher than any tablet — for a reason worth understanding. Oral drugs amplify a signal your body still has to generate: they need nerve conduction and endothelial function to work with. An injection does not ask permission. It relaxes the smooth muscle directly, which is why it keeps working in men where tablets have stopped — after prostate surgery, in long-standing diabetes, in significant vascular disease.

That is the case for it, and it is the strongest case for anything in this category. So why is it near the bottom of most lists? Because it is a needle, and men would rather take a tablet. That preference is entirely understandable and it is not a clinical argument.

On the combination itself: this is the one compounded blend on this site we would defend on its merits. The three drugs work by genuinely different mechanisms — alpha blockade plus two vasodilators — rather than stacking one class three times. The pairing exists for a practical reason: alprostadil alone causes an aching, burning pain in a meaningful minority of men, and combining it with papaverine and phentolamine allows a lower alprostadil dose while improving response. Urologists have used it this way for decades. It is off-label and unapproved as a combination, and it is also standard practice.

Now the part that decides whether this is safe for you, and it is not negotiable.

The first dose belongs in a clinic. Titration is done under supervision because the risk being managed is priapism — an erection that will not subside — and the therapeutic window varies enormously between men. A dose that is right for one man will be far too much for another whose problem is more psychological than vascular.

An erection lasting more than four hours is a urological emergency, not an inconvenience. Blood trapped in the corpora becomes deoxygenated and acidotic; beyond roughly six hours the tissue begins to be damaged, and beyond twelve the damage can be permanent, ending in fibrosis and a loss of function no drug reverses. Men who are treated within a few hours generally do well. Men who wait until morning because they are embarrassed sometimes do not. If you take this therapy on, you accept the obligation to go to an emergency department that night.

The other honest drawbacks: bruising, the occasional ache, and scarring at the injection site over time — which is why the three-to-four-times-weekly ceiling exists and why rotating the site matters. Men on anticoagulants or with sickle cell disease need a specific conversation before starting.

Where this leaves a reader. If tablets work for you, there is no reason to be here. If they have genuinely failed at a proper dose on more than one occasion, this is the option with the best odds and the lowest running cost, and the thing standing between you and it is a supervised first appointment and a willingness to use a very small needle. We have written about what that is actually like in [the needle you are imagining](/journal/injection-therapy-the-needle-you-are-imagining).