MUSE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MUSE (MUSE).
MUSE (alprostadil, prostaglandin E1) causes vasodilation and relaxation of trabecular smooth muscle in the corpus cavernosum via stimulation of adenylate cyclase, increasing intracellular cAMP levels, leading to penile erection.
| Metabolism | Primarily metabolized in the lungs via oxidation (15-hydroxy dehydrogenase) and reduction (13,14-reductase); also undergoes metabolism in the liver and kidneys. |
| Excretion | Renal: <2% unchanged; biliary/fecal: minimal; primarily metabolized via local esterases in corpus cavernosum. |
| Half-life | Terminal half-life: 0.5–1 hour; clinical context: effect limited to duration of erection, no systemic accumulation. |
| Protein binding | ~93% bound to albumin (low affinity). |
| Volume of Distribution | 0.7–1.2 L/kg (not clinically relevant due to local administration). |
| Bioavailability | Intraurethral: ~0.5–1% of dose absorbed systemically; most remains locally active. |
| Onset of Action | Intraurethral: 5–10 minutes. |
| Duration of Action | 30–60 minutes; erection occurs within 5–10 min and lasts depending on sexual stimulation. |
125-250 mcg intraurethrally, as needed, with a maximum of 2 doses per 24 hours.
| Dosage form | SUPPOSITORY |
| Renal impairment | No dose adjustment required for renal impairment; drug is locally administered and systemic absorption minimal. |
| Liver impairment | No dose adjustment required for hepatic impairment; drug is locally administered and systemic absorption minimal. |
| Pediatric use | Not approved for use in pediatric patients (safety and efficacy not established). |
| Geriatric use | No specific dose adjustment recommended; use with caution due to potential increased sensitivity to hypotensive effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MUSE (MUSE).
| Breastfeeding | Not recommended during breastfeeding. M/P ratio not established. Excretion in human milk unknown; may cause adverse effects in infant. |
| Teratogenic Risk | FDA Pregnancy Category C. First trimester: No adequate studies; animal studies show embryotoxicity at high doses. Second and third trimesters: Limited data; use only if potential benefit justifies risk. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to alprostadil or any component of the product","Conditions predisposing to priapism (e.g., sickle cell anemia, multiple myeloma, leukemia)","Penile deformity (e.g., angulation, cavernosal fibrosis, Peyronie's disease)","Urethral stricture or urethritis","Use in men for whom sexual activity is inadvisable (e.g., severe cardiovascular disease)"]
| Precautions | ["Priapism: prolonged erection >4 hours requires immediate medical attention.","Syncope and hypotension may occur, particularly with initial use.","Urethral bleeding or minor urethral trauma may occur.","Use with caution in patients with penile implants, urethral stricture, or balanitis.","Not for use with sexual partners who are pregnant or may become pregnant unless a condom is used (risk to fetus not fully established)."] |
Loading safety data…
| Monitor blood pressure, heart rate, and signs of hypotension. Fetal heart rate monitoring recommended during administration. Assess for uterine hyperstimulation if used for cervical ripening. |
| Fertility Effects | No known adverse effects on female or male fertility based on limited data. May transiently alter menstrual cycle patterns. |