alprostadil intracavernous/urethral (Rx)

>10%

Urethral suppository

• Penile pain (32%)
• Urethral burning (12%)

Intracavernous injection

• Penile pain (37%)

1-10%

Urethral suppository

• Urethral bleeding/spotting (5%)
• Testicular pain (5%)
• Headache (3%)

Intracavernous injection

• Prolonged erection, 4-6 hr (4%)
• Penile fibrosis (3%)
• Injection site hematoma (3%)
• Injection site echymosis (2%)
• Penile rash (1%)
• Penile edema (1%)

<1%

Urethral suppository

• Syncope (0.4%)
• Tachycardia, leg pain, perineal pain

Intracavernous injection

• Priapism, >6 hr (0.4%)
• Injection site hemorrhage

Postmarketing Reports

Intracavernous injection device failure

Contraindications

Hypersensitivity

Women

Newborns

Predisposition to priapism (eg, sickle cell anemia, sickle cell trait, multiple myeloma, leukemia)

Anatomical deformation of the penis, such as cavernosal fibrosis or Peyronie’s disease

Penile implants

Sexual intercourse with pregnant woman unless condom barrier used (intracavernosal implant)

When sexual activity is inadvisable

Cautions

Discontinue therapy if signs of penile fibrosis develop

Contact physician or seek immediate medical assistance if erection persists >4 hr (treat immediately to avoid permanent lose of potency

The preservative benzyl alcohol contained in the intracavernosal dosage form has been associated with serious adverse events, including the “gasping syndrome”, and death in pediatric patients; this dosage form is not indicated for pediatric patients

Syncope reported within 1 hr of using urethral suppository (pellet)

The risk of breakage with superfine needles is high; needle breakage, with a portion of the needle remaining in the penis, requiring hospitalization and surgical removal reported; careful instruction in proper patient handling and injection techniques may minimize potential for breakage

Patients with bleeding disorders or on anticoagulants, such as warfarin or heparin may have increased propensity for bleeding after intracavernosal injection; use caution; compress site of injection with alcohol swab or sterile gauze for 5 min

Diagnose and treat underlying treatable medical causes of erectile dysfunction before initiating therapy

Safety and efficacy of combination with other vasoactive agents have not been studied; not recommended

Priapism reported; to minimize chances of this occurring, titrate dose slowly to the lowest effective dose; advise patients to seek immediate medical assistance for an erection that persists longer than 4 hours

Injections can lead to increased peripheral blood levels of alprostadil, especially in patients with significant corpora cavernosa venous leakage; avoid use in patients with known cavernosal venous leakage; may cause hypotension

Counsel patients about protective measures necessary to guard against sexually transmitted disease including human immunodeficiency virus (HIV)

Pregnancy: Alprostadil not indicated for use in females

Lactation: Alprostadil not indicated for use in females

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

Mechanism of Action

Relaxes arterial smooth muscle, producing vasodilation; allows blood flow and entrapment in the lacunar spaces of the penis

Pharmacokinetics

Half-Life: 5-10 min

Onset: ED (intraurethral; muse): 30-60 min

Protein bound: 81%

Metabolism: chiefly in lungs via enzymatic oxidation (plasma levels may be higher in patients with pulmonary disease)

Metabolites: Prostanoid metabolites (inactive)

Excretion: Mainly in urine 90%, small amount in lung