Alprostadil is a medication used to treat erectile dysfunction (ED), a condition affecting over 150 million men worldwide where achieving or maintaining an erection sufficient for intercourse is difficult. It acts as a vasodilator, relaxing smooth muscle in the penis to increase blood flow and induce an erection. Available in forms like intracavernosal injections (Caverject), intraurethral pellets (MUSE), and topical cream (Vitaros), alprostadil serves as a second-line option when oral PDE5 inhibitors like sildenafil fail.
About alprostadil
Alprostadil is a synthetic analog of prostaglandin E1 (PGE1), naturally produced in the body. It promotes vasodilation by relaxing trabecular smooth muscle in the corpora cavernosa and cavernosal arteries, allowing arterial blood to fill lacunar spaces, expand them, and compress venous outflow for penile rigidity via the corporal veno-occlusive mechanism. Unlike PDE5 inhibitors, which require sexual stimulation to activate the nitric oxide pathway, alprostadil works independently of psychological or neurological factors, making it suitable for various ED etiologies including neurogenic, vasculogenic, psychogenic, or mixed.
Approved by the FDA in 1996 for ED via injection or suppository, alprostadil is prescription-only and highly effective, producing erections firm enough for intercourse in 80% of men regardless of age or ED cause. The cream form (Vitaros) received European marketing authorization in 2013.
Before taking alprostadil
Who can and cannot take alprostadil tablets, mini-pellets, or cream?
Alprostadil suits most adult men with ED but is contraindicated in those with:
- Known hypersensitivity to alprostadil or formulation components.
- Penile implants, anatomical deformities (e.g., Peyronie’s disease with angulation), or priapism history.
- Conditions predisposing to priapism (e.g., sickle cell anemia, leukemia).
- Injection form: urethral stricture, severe hypospadias, or current urethritis/balanitis.
Cautions apply for men with bleeding disorders, anticoagulant use, or penile fibrosis. Consult a doctor if you have cardiovascular disease, as ED may signal underlying issues.
Other medicines, food, and drink – things to avoid
Alprostadil has minimal drug interactions due to local action. Unlike PDE5 inhibitors, it is safe with nitrates or alpha-blockers. Avoid combining injection and pellet forms concurrently to prevent overdose. No food/drink restrictions; alcohol does not interact but may worsen ED.
Pregnancy, breastfeeding, and fertility
Alprostadil is male-only for ED. Systemic absorption is low (3% AEs), posing negligible risk to female partners or fertility. Condom use recommended if partner is pregnant, though no evidence of harm.
Dosage and strength
| Form | Dosages | Notes |
|---|---|---|
| Caverject (Injection) | 5, 10, 20, 40 mcg | Start 2.5-5 mcg; max 60 mcg/dose, 3x/week, 24h apart. |
| MUSE (Pellet) | 125, 250, 500, 1000 mcg | Start 125 mcg; max 3x/week, 24h apart. |
| Vitaros (Cream) | 100, 200, 300 mcg | Titrate from 200 mcg; 300 mcg optimal for severe ED. |
Dosages are individualized; highest efficacy at 300 mcg cream (83% in severe ED).
How and when to take alprostadil
Dosage
Follow prescribed dose; do not exceed. Titrate based on response: injections start low to minimize pain/priapism risk.
Your doses
- Injections (Caverject): Inject into corpora cavernosa side; erection in 5-20 min, lasts 1h.
- Pellets (MUSE): Insert into urethra via applicator; erection in 10 min.
- Cream (Vitaros): Apply to meatus, wait 5-30 min (peak at 30 min).
Alprostadil injection
Reconstitute powder with diluent, inject 2.5-60 mcg laterally into penis base/shaft (alternate sides). Clean site, use 0.5-1 inch needle at 90°. Erection occurs in 5-20 min; intercourse within 1h. Dispose safely.
Alprostadil mini-pellet
Urinate first to moisten urethra. Insert pellet 2.5 cm into opening with applicator (shake 10s, press). Maintain 10 min for dissolution. Erection in 10 min, lasts ~1h. Less effective (30-40%) than injection.
Alprostadil cream
Apply pea-sized amount (100-300 mcg) to meatus using single-use applicator. Do not exceed dose; rub in gently. Onset 5-30 min, effective up to 83% in trials.
When to take it
10-30 min before sex. Limit to 3x/week, 24h between doses to avoid tolerance/priapism.
Missed dose or product not used correctly
No scheduled doses; if no erection, check technique/dose. Consult doctor if persistent failure.
Side effects and safety
Most AEs are mild/moderate, local, transient (65% local, 3% systemic). Penile pain common (injection > pellet > cream).
| Form | Common Side Effects (>1/100) | Serious (<1/1000) |
|---|---|---|
| Injection | Penile pain, fibrosis, priapism, hematoma | Priapism, hypotension |
| MUSE | Urethral/perineal pain, minor bleeding | Priapism, syncope |
| Cream | Penile erythema/pain, urethral burning | Systemic: headache, dizziness (rare) |
Report prolonged erection (>4h) as emergency; seek immediate care.
Common side effects
- Penile pain/itching (up to 37% injection).
- Urethral burning (MUSE/cream).
Serious side effects
- Priapism: Painful erection >4h; treat urgently to prevent damage.
- Fibrosis/scarring with overuse.
- Hypotension, especially if absorbed systemically.
Long-term use
Incidence decreases over time (34% after 6 months). Monitor for fibrosis; regular check-ups advised.
How to cope with alprostadil side effects
- Pain: Use lowest effective dose; ice pack post-injection; cream/pellet less painful.
- Bleeding: Apply pressure 5 min.
- Priapism: Seek ER; self-injection phenylephrine may be taught.
- Partner education on application reduces anxiety.
Pregnancy, breastfeeding, and low blood sugars
No issues for ED use; local action minimizes transfer. Diabetics: stable blood sugar aids efficacy.
Other medicines, food, and drink
Safe with most; no CYP450 interactions. Caution with antihypertensives.
Comparisons between forms
| Aspect | Caverject (Injection) | MUSE (Pellet) | Vitaros (Cream) |
|---|---|---|---|
| Efficacy | 80%+ | 30-40% | Up to 83% (severe ED) |
| Onset | 5-20 min | 10 min | 5-30 min |
| Pain | High | Moderate | Low |
| Convenience | Low (needle) | Medium | High (topical) |
Injections most reliable; cream ideal for needle-phobic.
Further information
Store injections refrigerated; pellets/cream at room temp. Discard expired. Partner involvement improves adherence. Lifestyle: exercise, quit smoking enhance results.
1. About alprostadil
(Repeated for FAQ structure; see above.)
Frequently Asked Questions
Q: How effective is alprostadil?
A: Injections: 80%+ success; pellets: 30-40%; cream: 83% in severe ED per phase III trials.
Q: How quick does it work?
A: 5-30 min; intercourse after 10 min wait.
Q: Can I use with Viagra?
A: Not recommended without doctor approval; risk of priapism.
Q: Is it safe long-term?
A: Yes, with monitoring; AEs decrease over time.
Q: Does insurance cover it?
A: Varies; prescription required.
References
- Alprostadil cream in the treatment of erectile dysfunction — NIH/PMC. 2016-11-11. https://pmc.ncbi.nlm.nih.gov/articles/PMC5131739/
- Alprostadil: Uses, Interactions, Mechanism of Action — DrugBank. 2023-01-01. https://go.drugbank.com/drugs/DB00770
- Alprostadil Injection and Suppository for Erectile Dysfunction — WebMD. 2024-01-01. https://www.webmd.com/erectile-dysfunction/guide/alprostadil-treat-ed
- Alprostadil – StatPearls — NCBI Bookshelf. 2023-07-17. https://www.ncbi.nlm.nih.gov/books/NBK542217/
- Erectile dysfunction: Alprostadil cream – NICE — NICE. 2023-01-01. https://www.nice.org.uk/advice/esnm50/chapter/full-evidence-summary
- Alprostadil: Types, Uses & Side Effects — Cleveland Clinic. 2024-01-01. https://my.clevelandclinic.org/health/treatments/10051-alprostadil
- Alprostadil (intracavernosal route) — Mayo Clinic. 2024-01-01. https://www.mayoclinic.org/drugs-supplements/alprostadil-intracavernosal-route/description/drg-20067404
