Dosage and Titration
Initial dosage as recommended in the package insert for both Edex and Caverject Impulse is 2.5 mcg with a second dose of 2.5 mcg to be given if the initial dose is inadequate. It is than recommended that the dose be increased by 5 to 10 mcg intervals at each attempt (a minimum of 24 hours apart) depending on the erectile response with each dose (up to a maximum dose of 40 mcg). Higher doses for intracavernosal injections are needed in older men age 63 to 85 requiring 50% stronger dosages to achieve erections (comparing an average age of men of 47 in the younger group to and average age of 70 in the older group), which supports an initial dose of 10 mcg with men who are 65 and older (Richter, Vardi, Ringel, Shalev, & Nissenkorn, 2001). It is my experience that initial doses of 10 mcg are most commonly administered as an initial dose and well tolerated in men over 65 except those who had a prostatectomy in the last 2 years (these men were more likely to experience the pain or ache side effect with prostaglandin). If the patient had a prostatectomy in the past 2 years and/or is under 65, the test dose is decreased to 5 mcg most commonly, and 2.5 mcg if the patient is both under 55 and had his prostatectomy within the last year.
Utilization of intracavernosal injections by investigators reveals varied initial dosing and titration regimens. In one study, titration with alprostadil (prostaglandin E1) was started at the 5 mcg dose and increased by intervals of 5 mcg with most of the men responding to the 2.5 to 15 mcg range (Brock, Tu, & Linet, 2001). Montorsi et al. (2002) also began with an initial dose of 5 mcgs and titrated to an effective dose of prostaglandin. Another investigator used a 5 mcg starting dose initially and switched to 10 mcgs in subsequent studies as a starting dose with titration of medication up to 40 mcg (Goldstein et al., 2000). Richter et al. (2001) used a starting dose of 5 mcg with all patients, titrating up by 5 mcg to achieve an erection sufficient for sexual relations with a maximum dose of 30 mcg.
Typically trimix (papaverine 30 mg, phentolamine 1 mg, and prostaglandin E1 10 mcg) and bimix (papaverine 30 mg and phentolamine 1 mg) are started at a dose of 0.1 to 0.5 ml in my clinic depending on the patient's age and concomitant problems for ED. Investigators have utilized dose volumes of trimix (papaverine 30 mg, phentolamine 1 mg, and prostaglandin E1 10 mcg per 1 ml) ranging from 0.18 to 1.0 ml in previous studies (Bennett, Carpenter, & Barada, 1991; Montorsi et al., 2002; Mulhall et al., 1999). One physician, who only sends post prostatectomy patients for referral, prefers only trimix with post radical prostatectomy patients related to the side effect of pain with monotherapy using prostaglandin E1. For this reason, this physician's patients are immediately started on dose titration of trimix, foregoing the monotherapy with prostaglandin E1/alprostadil.
Urol Nurs. 2006;26(6):449-453. © 2006 Society of Urologic Nurses and Associates
Cite this: Intracavernosol Injection Algorithm - Medscape - Dec 01, 2006.