alprostadil intracavernous/urethral (Caverject, Edex, Muse, PGE1, Prostaglandin E1, Viridal)

Dosing and uses of Caverject, Edex (alprostadil intracavernous/urethral)

• Adult
• Pediatric

 

Adult dosage forms and strengths

alprostadil intracavernous/urethraL

kit, intracavernosaL

• 10mcg
• 20mcg
• 40mcg

solution, injection

• 500 mcg/mL

solution reconstituted, intracavernosaL

• 20mcg
• 40mcg

urethral suppository/pellet

• 125mcg
• 250mcg
• 500mcg
• 1000mcg

 

Erectile Dysfunction

Vascular, Psychogenic, or Mixed Etiology

• Initial 2.5 mcg intracavernosal injection
• Titrate by 2.5 mcg, THEN by 5-10 mcg intervals until erection of <1 hr maintained; not to exceed 40 mcg (Edex) or 60 mcg (Caverject)
• If no absolute response to 2.5 mcg dose, may increase second dose to 7.5 mcg followed by increments of 5-10 mcg
• Once appropriate dose defined, patient may self-administer injections at a frequency <3 times/week with at least 24hr between doses

Neurogenic Ed

• Initial 1.25 mcg intracavernosal injection
• Titrate by 1.25 mcg-2.5 mcg, THEN by 2.5-5 mcg until erection of <1 hr maintained

Intraurethral suppository

• Dosage range: 125-1000 mcg intraurethral
• Start: 125-250 mcg until duration of action is about 30-60 min
• Not to exceed 2 systems per 24 hr

 

Administration

Intracavernous injection

• Use only the supplied diluent for reconstitution
• Use a 0.5-inch, 27- to 30-gauge needle Inject into the dorsolateral aspect of proximal third of penis, avoiding visible veins
• Alternate side of penis for injections
• Refrigerate at 2-8°C until dispensed
• After dispensing, stable for up to 3 months ≤25°C

 

Pediatric dosage forms and strengths

Contains benzoyl alcohol; this product is not indicated for children (see separate drug monograph for alprostadil IV for neonatal use to maintain patency of ductus arteriosus)

 

Caverject, Edex (alprostadil intracavernous/urethral) adverse (side) effects

>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

 

Warnings

Contraindications

Hypersensitivity

Women

Newborns

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

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

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

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

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

 

Pregnancy and lactation

Pregnancy category: X; C (Muse)

Lactation: Not indicated for use in women

 

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.

 

Pharmacology of Caverject, Edex (alprostadil intracavernous/urethral)

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