What is the appropriate dosage and administration of Caverjet (alprostadil) for an adult male with erectile dysfunction?

Caverject (Alprostadil) Prescription Example for Erectile Dysfunction

For an adult male with erectile dysfunction, begin intracavernosal alprostadil (Caverject) at 2.5 mcg for vasculogenic, psychogenic, or mixed etiology ED, or 1.25 mcg for pure neurogenic ED (spinal cord injury), with dose titration performed in-office until achieving an erection suitable for intercourse lasting no more than 1 hour. 1

Initial In-Office Dose Titration (Required Before Home Use)

All first injections must be performed in the physician's office by medically trained personnel—patients cannot begin self-injection until properly trained and the effective dose is established. 1

Starting Doses by Etiology:

• Vasculogenic, psychogenic, or mixed etiology ED: Start at 2.5 mcg 1

  • If partial response: increase by 2.5 mcg to 5 mcg
  • Then increase in 5-10 mcg increments based on response
  • If no response to initial 2.5 mcg: second dose may be 7.5 mcg, then 5-10 mcg increments 1

• Pure neurogenic ED (spinal cord injury): Start at 1.25 mcg 1

  • Increase by 1.25 mcg to 2.5 mcg
  • Then 2.5 mcg increment to 5 mcg
  • Then 5 mcg increments thereafter 1

Titration Protocol:

• Patient must remain in office until complete detumescence occurs 1
• If no response: next higher dose may be given within 1 hour 1
• If response occurs: wait at least 1 day before next dose 1
• Target: erection suitable for intercourse, duration ≤60 minutes 1, 2
• Dosage range: 1-40 mcg (doses >40 mcg not studied) 1

Typical Effective Doses from Clinical Studies

• Mean effective dose: 10.7 mcg (1-20 mcg range studies) or 21.9 mcg (1-40 mcg range studies) 1
• Median dose in diabetic men: 20 mcg (range 2.5-60 mcg) 3
• Median dose in arteriogenic ED: 15 mcg 4
• Success rate: 94-96% of men establish an effective dose 1, 4, 3

Home Self-Injection Instructions

Administration Technique:

• Use ½-inch, 27- to 30-gauge needle 1
• Inject into lateral aspect of proximal third of penis over 5-10 seconds 1
• Avoid visible veins 1
• Alternate injection site and side of penis with each use 1
• Cleanse injection site with alcohol swab before injection 1
• Discard any bent needles immediately—they may break 1

Frequency and Dosing:

• Maximum frequency: 3 times weekly with at least 24 hours between doses 1
• Use the lowest effective dose established during office titration 1
• If erection duration >1 hour: reduce dose 1
• Dose adjustments require physician consultation 1

Sample Prescription Format

Rx: Caverject (alprostadil for injection)

• Strength: [Insert dose established during titration, e.g., 10 mcg, 20 mcg]
• Quantity: #12 single-dose vials (for 1 month at maximum frequency)
• Directions: Inject [dose] mcg intracavernosally as directed, no more than 3 times weekly with at least 24 hours between doses. Use technique as demonstrated in office.
• Refills: 2 (with required 3-month follow-up visits)

Critical Safety Warnings

Absolute Requirements:

• An in-office injection test must be performed before prescribing for home use 5
• Patient must demonstrate competence with self-injection technique 1
• Reconstituted solution must be clear and used immediately 1
• Single-dose cartridge and needle are for one-time use only 1

Adverse Events to Counsel About:

• Penile pain: Occurs in 50% of men at some time but only after 11% of injections, usually mild 2; reported in 23-24% in other studies 4, 3
• Prolonged erection: 5-6% of men 2, 4
• Priapism: 1% of men 2
• Penile fibrotic complications: 1-2% 2, 4
• Hematoma/ecchymosis: 8% 2

Special Populations:

• Diabetic men: Alprostadil is effective and well-tolerated, with 99% satisfactory response rate during home phase 3
• Arteriogenic ED: Long-term treatment improves penile circulation with significant increases in peak systolic velocity 4
• Men with bleeding disorders or on anticoagulants: Use with extreme caution 5
• History of priapism: Use with caution 5

Follow-Up Requirements

• Visit physician every 3 months while on self-injection therapy 1
• Assess efficacy and safety at each visit 1
• Adjust dose if needed under physician supervision 1
• Monitor for return of spontaneous erections (reported in 85% of men with long-term use) 4

Common Pitfalls to Avoid

• Never prescribe for home use without completing in-office titration and training 1
• Do not allow patients to exceed their established optimal dose 1
• Ensure patients understand that prolonged application or excessive dosing can cause loss of erection due to penile numbness 5
• Verify proper injection technique—incorrect technique is a common cause of treatment failure 5