Injection therapy, done the careful way
Our most-used treatment for men whom tablets have not helped — it acts locally, where the problem is, and it is started under physician supervision in our office.
George W. Carroll, MD Florida license ME48111NPI 1073644985 Men’s sexual medicine since 1992
What it is
Injection therapy uses a compounded prescription medication — commonly known as Trimix — self-administered with a very fine needle to produce an erection by acting directly on the local blood vessels. Because it works locally rather than through the whole body, it is frequently the appropriate option for men who cannot use ED tablets — including men who take nitrate heart medication. How we work up erectile dysfunction →
The medication comes in a wide range of concentrations, so your prescription can be matched to your response — and adjusted over time — rather than issued as one-strength-fits-all.
Compounded medications are not FDA-approved; Dr. Carroll will discuss whether a compounded medication or an FDA-approved treatment is right for you.
It is dispensed in pre-filled syringes prepared for your dose. The practical rationale is simple: pre-measured dosing removes the drawing-up and measuring steps where handling errors can happen when patients fill syringes themselves from a vial.
How it starts here
- Your first dose happens in the office, usually during the diagnostic study — one visit identifies the cause and lets you experience the treatment under supervision, so you know exactly what it feels like and what it does before anything is prescribed.
- Dosing is set conservatively and adjusted gradually. Dr. Carroll’s standing rule is to err on the side of too little rather than too much, then refine from your actual response.
- You are trained before you go home. Technique is taught in the office, and dosing is dispensed in pre-filled form by the practice — with our office a phone call away. Where Dr. Carroll judges it useful, that can include more than one strength to work with, so the early adjustment happens without a second trip.
- Follow-up is scheduled, not optional. The dose is refined until it is right; once it is settled, follow-up moves to a routine 3-month check and then 6-month intervals, with refills managed through the practice on an as-needed basis.
Why we dispense pre-filled syringes
You never mix, measure, or draw up medication from a vial here — every dose leaves the office pre-filled and labeled.
The rationale is documented, not decorative: in the largest published review of self-injecting ED patients, 42% made at least one injection error — including dose self-adjustment and double-dosing, the kinds of errors that raise the risk of a prolonged erection. And across clinical studies in other fields of medicine, pre-filled syringes have been shown to reduce medication dosing errors compared with drawing doses from vials. Pre-measured dosing removes the steps where those errors happen.
Sources: Furtado et al., Journal of Sexual Medicine (2024) — injection errors in 1,368 self-injecting patients; Benhamou et al., Annals of Pharmacotherapy (2024) — systematic review of pre-filled syringes and medication errors.
Safety, stated plainly
- Priapism: seek emergency care for any erection lasting longer than 4 hours. Every injection patient receives this instruction and after-hours contact instructions.
- Your first, supervised dose is given where a prolonged response can be recognized and treated immediately — one of the reasons treatment starts in the office.
- Candidacy is screened at consultation; some conditions that predispose to prolonged erections rule injection therapy out, and Dr. Carroll will tell you if yours does.
Common questions
- Does the injection hurt?
- It is the question men ask most, and the worry is almost always bigger than the event. The needle is very fine and the amount injected is small. Most men tell Dr. Carroll afterwards that it was easier than they expected — and you find that out with him in the room, because your first dose is given here in the office rather than at home on your own.
- Why not just order something online?
- Because self-injected medication deserves a physician who has measured your blood flow, set your dose in person, and answers the phone. That supervision is the treatment — the vial is just a component. What we bill and what we don’t →
- How quickly does it work?
- It is used shortly before intimacy and acts locally. Whether it fits your case, and at what dose, is determined at evaluation.
Care provided by George Carroll, M.D.
Medically reviewed by George W. Carroll, MD (Florida license ME48111) · Reviewed August 2026
Discuss it privately with the physician
Even if you choose to do nothing, it’s worth knowing what’s going on. Dr. Carroll will tell you, and the decision stays yours. One call to our office starts it — no obligation, no pressure, and no one pushing you toward a decision.
Office hours: Mon–Fri 9:00 AM – 5:00 PM.