CAVERJECT IMPULSE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CAVERJECT IMPULSE (CAVERJECT IMPULSE).
Alprostadil is a synthetic prostaglandin E1 that causes vasodilation and relaxation of trabecular smooth muscle in the corpus cavernosum, leading to increased blood flow and penile erection.
| Metabolism | Primarily metabolized in the lungs (60-90%) via oxidation, with subsequent conjugation in the liver; metabolites excreted renally. |
| Excretion | Primarily metabolized in the lung by enzymatic hydrolysis; urinary excretion accounts for approximately 70-90% of the administered dose as metabolites, with less than 3% excreted unchanged in urine; fecal excretion is minimal (<1%). |
| Half-life | Terminal elimination half-life is approximately 1-2.5 minutes following intravenous administration, due to rapid pulmonary metabolism; after intracavernosal injection, local half-life is extended to about 30-60 minutes due to depot effect. |
| Protein binding | Approximately 80-90% bound to plasma proteins, primarily to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Very large apparent volume of distribution (0.3-0.6 L/kg) at steady state, indicating extensive tissue binding; clinical significance: limited systemic exposure due to rapid pulmonary metabolism. |
| Bioavailability | Intracavernosal injection: 100% (administered directly into corpus cavernosum); oral bioavailability is negligible (<0.1%) due to extensive first-pass metabolism; transdermal absorption is minimal. |
| Onset of Action | Intracavernosal injection: 5-20 minutes; onset is dose-dependent and occurs within 5-20 minutes in most patients. |
| Duration of Action | Erection lasting 30-60 minutes on average; prolonged erections (>4 hours) occur in up to 4% of patients and require immediate medical intervention. Duration is dose-related. |
2.5 to 60 mcg intracavernosal injection as needed for erection, maximum 3 times per week with at least 24 hours between doses. Initial dose: 2.5 mcg, titrate based on response.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment required for renal impairment; however, use with caution in patients with severe renal insufficiency due to potential prolonged drug effect. |
| Liver impairment | No specific dose adjustment required for hepatic impairment; however, use with caution in patients with severe hepatic insufficiency (Child-Pugh class C) due to reduced drug clearance. |
| Pediatric use | Not recommended for use in pediatric patients (safety and efficacy not established). |
| Geriatric use | Initiate at lowest dose (2.5 mcg) with careful titration due to increased sensitivity and potential for priapism in elderly patients. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CAVERJECT IMPULSE (CAVERJECT IMPULSE).
| Breastfeeding | Not recommended. No data on alprostadil excretion in human milk. M/P ratio unknown. |
| Teratogenic Risk | Pregnancy category B. No evidence of fetal harm in animal studies; no adequate human studies in pregnant women. Risk cannot be ruled out. |
| Fetal Monitoring | Monitor for maternal hypotension and priapism. Fetal heart rate monitoring may be considered if used during pregnancy. |
■ FDA Black Box Warning
Prolonged erection (priapism) lasting more than 4 hours may occur; immediate medical attention required to avoid penile tissue damage and permanent loss of potency. Risk of priapism increases with doses above 20 mcg.
| Serious Effects |
["Hypersensitivity to alprostadil","Predisposition to priapism (sickle cell anemia, multiple myeloma, leukemia)","Penile anatomical deformities (e.g., severe angulation, cavernosal fibrosis)","Peyronie's disease","Penile implants","Use in women, children, or men who cannot achieve erection without drug therapy"]
| Precautions | ["Priapism risk: advise patient to seek emergency care if erection lasts >4 hours","Penile fibrosis: monitor for fibrotic changes with repeated use","Hematoma/ecchymosis at injection site","Use with caution in patients with bleeding disorders or on anticoagulants","Caution in patients with penile implants, anatomical deformities (e.g., Peyronie's disease), or sickle cell disease"] |
| Food/Dietary | No clinically significant food interactions. Avoid alcohol consumption immediately before or after injection as it may reduce effectiveness or increase dizziness. |
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| Fertility Effects | No known adverse effects on fertility in males; intended for erectile dysfunction, not for women. |
| Clinical Pearls | Alprostadil (PGE1) administered intracavernosally causes erection within 5-20 minutes; avoid use in men with priapism risk (sickle cell, multiple myeloma, leukemia) or anatomical penile deformities. Maximum of 3 doses per week and no more than 1 dose per 24 hours. Titrate dose cautiously; first dose must be administered under medical supervision. Use a 1/2-inch, 27-30 gauge needle for injection. Consider dose reduction if erection lasts >1 hour; immediate medical attention required if >4 hours. |
| Patient Advice | Do not use more than 3 times per week or more than once in 24 hours. · Inject at the base of the penis at a 90-degree angle into the side (corpora cavernosa). · Rotate injection sites (right and left sides of penis) to minimize fibrosis. · Apply firm pressure to injection site for 5 minutes after use to prevent bruising. · Seek immediate medical help if erection lasts longer than 4 hours (priapism). · Do not drive or operate machinery until you know how the drug affects you (dizziness possible). · Inform your doctor if you have a penile implant, curvature, or conditions causing priapism. · Use proper sharps disposal; do not reuse needles. |