Alprostadil

MEDICATION SAFETY ISSUES
Sound-alike/look-alike issues:
Alprostadil may be confused with alPRAZolam

U.S. BRAND NAMES — Caverject Impulse®; Caverject®; Edex®; Muse®; Prostin VR Pediatric®

PHARMACOLOGIC CATEGORY
Prostaglandin
Vasodilator

DOSING: ADULTS
Erectile dysfunction:
Intracavernous (Caverject®, Edex®): Individualize dose by careful titration; doses >40 mcg (Edex®) or >60 mcg (Caverject®) are not recommended: Initial dose must be titrated in physician's office. Patient must stay in the physician's office until complete detumescence occurs; if there is no response, then the next higher dose may be given within 1 hour; if there is still no response, a 1-day interval before giving the next dose is recommended; increasing the dose or concentration in the treatment of impotence results in increasing pain and discomfort.
Vasculogenic, psychogenic, or mixed etiology: Initiate dosage titration at 2.5 mcg, increasing by 2.5 mcg to a dose of 5 mcg and then in increments of 5-10 mcg depending on the erectile response until the dose produces an erection suitable for intercourse, not lasting >1 hour; if there is absolutely no response to initial 2.5 mcg dose, the second dose may be increased to 7.5 mcg, followed by increments of 5-10 mcg
Neurogenic etiology (eg, spinal cord injury): Initiate dosage titration at 1.25 mcg, increasing to a dose of 2.5 mcg and then 5 mcg; increase further in increments 5 mcg until the dose is reached that produces an erection suitable for intercourse, not lasting >1 hour
Maintenance: Once appropriate dose has been determined, patient may self-administer injections at a frequency of no more than 3 times/week with at least 24 hours between doses
Intraurethral (Muse® Pellet):
Initial: 125-250 mcg
Maintenance: Administer as needed to achieve an erection; duration of action is about 30-60 minutes; use only two systems per 24-hour period

DOSING: PEDIATRIC

(For additional information see "Alprostadil: Pediatric drug information")
Patent ductus arteriosus I.V.:
Prostin VR Pediatric®: I.V. continuous infusion into a large vein, or alternatively through an umbilical artery catheter placed at the ductal opening: 0.05-0.1 mcg/kg/minute with therapeutic response, rate is reduced to lowest effective dosage. With unsatisfactory response, rate is increased gradually; maintenance: 0.01-0.4 mcg/kg/minute.
Note: PGE1 is usually given at an infusion rate of 0.1 mcg/kg/minute, but it is often possible to reduce the dosage to 1/2 or even 1/10 without losing the therapeutic effect. The mixing schedule is shown in the table.

Mixing Schedule

Note: 500 mcg equals 1 ampul. For a concentration of 2 mcg/mL, add 500 mcg to 250 mL; infuse at 0.05 mL/kg/minute (72 mL/kg/24 hours) For a concentration of 5 mcg/mL, add 500 mcg to 100 mL; infuse at 0.02 mL/kg/minute (28.8 mL/kg/24 hours) For a concentration of 10 mcg/mL, add 500 mcg to 50 mL; infuse at 0.01 mL/kg/minute (14.4 mL/kg/24 hours) For a concentration of 20 mcg/mL, add 500 mcg to 25 mL; infuse at 0.005 mL/kg/minute (7.2 mL/kg/24 hours)

Note: Therapeutic response is indicated by increased pH in those with acidosis or by an increase in oxygenation (PO2) usually evident within 30 minutes.

DOSING: ELDERLY — Elderly patients may have a greater frequency of renal dysfunction; lowest effective dose should be used. In clinical studies with Edex®, higher minimally effective doses and a higher rate of lack of effect were noted. dosing.

DOSAGE FORMS — Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Injection, powder for reconstitution:
Caverject®: 20 mcg, 40 mcg [contains lactose; diluent contains benzyl alcohol]
Caverject Impulse®: 10 mcg, 20 mcg [prefilled injection system; contains lactose; diluent contains benzyl alcohol]
Edex®: 10 mcg, 20 mcg, 40 mcg [contains lactose; packaged in kits containing diluent, syringe, and alcohol swab]

Injection, solution: 500 mcg/mL (1 mL)
Prostin VR Pediatric®: 500 mcg/mL (1 mL) [contains dehydrated alcohol]

Pellet, urethral:
Muse®: 125 mcg (6s) [DSC], 250 mcg (6s), 500 mcg (6s), 1000 mcg (6s)

DOSAGE FORMS: CONCISE
Injection, powder for reconstitution:
Caverject®: 20 mcg, 40 mcg
Caverject Impulse®: 10 mcg, 20 mcg
Edex®: 10 mcg, 20 mcg, 40 mcg

Injection, solution: 500 mcg/mL (1 mL)
Prostin VR Pediatric®: 500 mcg/mL (1 mL)

Pellet, urethral:
Muse®: 250 mcg (6s), 500 mcg (6s), 1000 mcg (6s)

GENERIC EQUIVALENT AVAILABLE — Yes: Solution for injection

ADMINISTRATION — Erectile dysfunction: Use a 1/2 inch, 27- to 30-gauge needle. Inject into the dorsolateral aspect of the proximal third of the penis, avoiding visible veins; alternate side of the penis for injections.

USE
Prostin VR Pediatric®: Temporary maintenance of patency of ductus arteriosus in neonates with ductal-dependent congenital heart disease until surgery can be performed. These defects include cyanotic (eg, pulmonary atresia, pulmonary stenosis, tricuspid atresia, Fallot's tetralogy, transposition of the great vessels) and acyanotic (eg, interruption of aortic arch, coarctation of aorta, hypoplastic left ventricle) heart disease.

Caverject®: Treatment of erectile dysfunction of vasculogenic, psychogenic, or neurogenic etiology; adjunct in the diagnosis of erectile dysfunction

Edex®, Muse®: Treatment of erectile dysfunction of vasculogenic, psychogenic, or neurogenic etiology

USE - UNLABELED / INVESTIGATIONAL — Investigational: Treatment of pulmonary hypertension in infants and children with congenital heart defects with left-to-right shunts

ADVERSE REACTIONS SIGNIFICANT
Intraurethral:

>10%: Genitourinary: Penile pain, urethral burning

2% to 10%:
Central nervous system: Headache, dizziness, pain
Genitourinary: Vaginal itching (female partner), testicular pain, urethral bleeding (minor)

<2% (Limited to important or life-threatening): Tachycardia, perineal pain, leg pain

Intracavernosal injection:

>10%: Genitourinary: Penile pain

1% to 10%:
Cardiovascular: Hypertension
Central nervous system: Headache, dizziness
Genitourinary: Prolonged erection (>4 hours, 4%), penile fibrosis, penis disorder, penile rash, penile edema
Local: Injection site hematoma and/or bruising

<1% (Limited to important or life-threatening): Balanitis, injection site hemorrhage, priapism (0.4%)

Intravenous:

>10%:
Cardiovascular: Flushing
Central nervous system: Fever
Respiratory: Apnea

1% to 10%:
Cardiovascular: Bradycardia, hyper-/hypotension, tachycardia, cardiac arrest, edema
Central nervous system: Seizure, headache, dizziness
Endocrine & metabolic: Hypokalemia
Gastrointestinal: Diarrhea
Hematologic: Disseminated intravascular coagulation
Neuromuscular & skeletal: Back pain
Respiratory: Upper respiratory infection, flu syndrome, sinusitis, nasal congestion, cough
Miscellaneous: Sepsis, localized pain in structures other than the injection site

<1% (Limited to important or life-threatening): Anemia, anuria, bleeding, bradypnea, bronchial wheezing, cerebral bleeding, CHF, gastric regurgitation, hematuria, hyperbilirubinemia, hyperemia, hyperextension of neck, hyperirritability, hyperkalemia, hypoglycemia, hypothermia, jitteriness, lethargy, peritonitis, second-degree heart block, shock, stiffness, supraventricular tachycardia, thrombocytopenia, ventricular fibrillation

CONTRAINDICATIONS — Hypersensitivity to alprostadil or any component of the formulation; hyaline membrane disease or persistent fetal circulation and when a dominant left-to-right shunt is present; respiratory distress syndrome; conditions predisposing patients to priapism (sickle cell anemia, multiple myeloma, leukemia); patients with anatomical deformation of the penis, penile implants; use in men for whom sexual activity is inadvisable or contraindicated; pregnancy

WARNINGS / PRECAUTIONS
Boxed warnings: Apnea: .

Concerns related to adverse effects: Apnea: [U.S. Boxed Warning]: Apnea may occur in 10% to 12% of neonates with congenital heart defects, especially in those weighing <2 kg at birth. Apnea usually appears during the first hour of drug infusion.

Disease-related concerns: Erectile dysfunction: Appropriate use: When used in erectile dysfunction, priapism may occur; patient must be instructed to report to physician or seek immediate medical assistance if an erection persists for longer than 4 hours. Treat immediately to avoid penile tissue damage and permanent loss of potency; discontinue therapy if signs of penile fibrosis develop (penile angulation, cavernosal fibrosis, or Peyronie's disease). Patency of ductus arteriosus: Appropriate use: Infuse for the shortest time at the lowest dose consistent with good patient care. Use for >120 hours has been associated with antral hyperplasia and gastric outlet obstruction.

Special populations: Neonates: Use with caution in neonates with bleeding tendencies.

Dosage form specific issues: Muse®: When used in erectile dysfunction, syncope occurring within 1 hour of administration has been reported. The potential for drug-drug interactions may occur when prescribed concomitantly with antihypertensives. Some lowering of blood pressure may occur without symptoms, and swelling of leg veins, leg pain, perineal pain, and rapid pulse have been reported in <2% of patients during in-clinic titration and home treatment.

DRUG INTERACTIONS — There are no known significant interactions.

ETHANOL / NUTRITION / HERB INTERACTIONS — Ethanol: Avoid concurrent use (vasodilating effect).

PREGNANCY RISK FACTOR — X/C (show table) (Muse®)

PREGNANCY IMPLICATIONS — Alprostadil is embryotoxic in animal studies. It is not indicated for use in women. The manufacturer of Muse® recommends a condom barrier when being used during sexual intercourse with a pregnant women.

LACTATION — Not indicated for use in women

PRICING — (data from drugstore.com)
Kit (Caverject Impulse)
10 mcg (2): $71.43
20 mcg (2): $90.72

Kit (Edex)
10 mcg (1): $72.17
10 mcg (1): $204.41
20 mcg (1): $91.09
20 mcg (1): $246.76
40 mcg (1): $126.38
40 mcg (1): $338.44

Pellet (Muse)
125 mcg (6): $162.43
250 mcg (6): $169.11
500 mcg (6): $180.24
1000 mcg (6): $195.82

Solution (reconstituted) (Caverject)
20 mcg (6): $248.38
40 mcg (6): $291.57

MONITORING PARAMETERS — Arterial pressure, respiratory rate, heart rate, temperature, degree of penile pain, length of erection, signs of infection

CANADIAN BRAND NAMES — Caverject®; Muse® Pellet; Prostin® VR

INTERNATIONAL BRAND NAMES — Alostin (KP); Alprostapint (BG, HU, PL); Befar (HK); Caverject (AE, AR, AT, BB, BH, BM, BO, BR, BS, BZ, CN, CO, CR, CY, DE, DO, EC, EE, EG, FR, GB, GT, GY, HN, HU, IE, IL, IQ, IR, JM, JO, KW, LB, LU, LY, MX, MY, NI, NL, NO, NZ, OM, PA, PE, PL, PR, PT, PY, QA, SA, SE, SG, SR, SV, SY, TT, TW, UY, VE, YE, ZA); Caverject Dual Chamber (FR, HK); Caverject Impulse (AU); Caverjet (IL); Edex (FR, PL); Eglandin (KP); Gaverject (PK); Liple (JP); Lyple (JP); Minprog (AT); Muse (AE, BH, CY, EG, GB, IE, IL, IQ, IR, JO, KW, LB, LY, OM, QA, SA, SY, YE, ZA); Palux (JP); Prink (KP); Promostan (TW); Prostandin (JP, KP); Prostavasin (AR, BR, CL, HU, LU, PH, PL, UY); Prostin (CZ); Prostin Pediatrico (CN); Prostin VR (AE, AU, BE, BH, CH, CO, CY, EG, GB, GR, HN, HU, IL, IN, IQ, IR, IT, JO, KW, LB, LY, NL, OM, PL, QA, SA, SY, TH, TW, YE, ZA); Prostin VR Paedeatric (MY); Prostine VR (FR); Prostivas (DK, FI, NO, SE); Sugiran (ES); Viridal (DE)

MECHANISM OF ACTION — Causes vasodilation by means of direct effect on vascular and ductus arteriosus smooth muscle; relaxes trabecular smooth muscle by dilation of cavernosal arteries when injected along the penile shaft, allowing blood flow to and entrapment in the lacunar spaces of the penis (ie, corporeal veno-occlusive mechanism)

PHARMACODYNAMICS / KINETICS
Onset of action: Rapid

Duration: <1 hour

Distribution: Insignificant following penile injection

Protein binding, plasma: 81% to albumin

Metabolism: ~75% by oxidation in one pass via lungs

Half-life elimination: 5-10 minutes

Excretion: Urine (90% as metabolites) within 24 hours

PATIENT INFORMATION — Store in refrigerator; if self-injecting for the treatment of impotence, dilute with the supplied diluent and use immediately after diluting; see prescriber at least every 3 months to ensure proper technique and for dosage adjustment. Alternate sides of the penis with each injection; do not inject more than 3 times/week, allowing at least 24 hours between each dose; dispose of the syringe, needle, and vial properly; discard single-use vials after each use; report moderate to severe penile pain or erections lasting >4 hours to a prescriber immediately; inform a prescriber as soon as possible if any new penile pain, nodules, hard tissue, or signs of infection develop; the risk of transmission of blood-borne diseases is increased with use of alprostadil injections since a small amount of bleeding at the injection site is possible. Do not drive or operate heavy machinery within 1 hour of administration.