alprostadil intracavernous/urethral (Caverject, Edex, Muse, PGE1, Prostaglandin E1, Viridal)
Classes: Prostaglandins, Genitourinary
Dosing and uses of Caverject, Edex (alprostadil intracavernous/urethral)
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