Caverject Impulse

Alprostadil is a potent prostaglandin E1 (PGE1) analog used clinically for the treatment of erectile dysfunction and the temporary maintenance of ductus arteriosus patency in neonates with congenital heart defects.

Dosage for Alprostadil is highly individualized and must be titrated (carefully adjusted) by a healthcare provider to find the lowest effective dose that produces a satisfactory erection not exceeding one hour in duration.

Intracavernosal Injection (e.g., Caverject, Edex)

• Initial Dose: For ED of vasculogenic, psychogenic, or mixed etiology, the starting dose is typically 2.5 mcg. For ED of pure neurogenic origin (e.g., spinal cord injury), the starting dose is often lower, at 1.25 mcg.
• Titration: If there is no response, the dose may be increased in increments of 2.5 mcg to 5 mcg until the desired response is achieved. Most men find an effective dose between 5 mcg and 20 mcg.
• Maximum Frequency: Do not use more than 3 times per week, with at least 24 hours between each dose.

Intraurethral Suppository (e.g., MUSE)

• Initial Dose: The usual starting dose is 125 mcg or 250 mcg.
• Titration: Based on the response, the dose may be increased to 500 mcg or 1000 mcg under medical supervision.
• Maximum Frequency: No more than 2 doses should be used within a 24-hour period.

Alprostadil (Prostin VR Pediatric) is used in neonates to maintain the patency of the ductus arteriosus. It is administered via continuous intravenous or intra-arterial infusion.

• Standard Infusion Rate: The initial dose is typically 0.05 to 0.1 mcg per kilogram of body weight per minute (mcg/kg/min).
• Maintenance: Once a therapeutic response is achieved (e.g., increased oxygen saturation or improved blood pressure), the infusion rate is usually reduced to the lowest possible dose (often 0.01 to 0.05 mcg/kg/min) that maintains the effect.

Renal Impairment

Because Alprostadil is primarily metabolized in the lungs, significant dose adjustments are generally not required for patients with renal impairment when used for ED. However, caution is advised in neonates with renal dysfunction as it may affect the clearance of metabolites.

Hepatic Impairment

No specific dosage adjustments are typically provided for hepatic impairment, but since the liver plays a secondary role in metabolism, patients with severe liver disease should be monitored closely for systemic side effects.

Elderly Patients

Clinical studies have not identified significant differences in response between older and younger men. However, elderly patients may have a higher prevalence of cardiovascular disease, necessitating a cautious approach to the initial dose.

Intracavernosal Injection

1. 1Preparation: Wash your hands and clean the injection site on the side of the penis with an alcohol swab. Avoid any visible veins.
2. 2Injection: Use a 27- to 30-gauge needle. Insert the needle at a 90-degree angle into the corpus cavernosum (the 2 o'clock or 10 o'clock positions).
3. 3Post-Injection: Apply pressure to the injection site for at least 5 minutes to prevent bruising (hematoma).

Intraurethral Suppository

1. 1Urination: It is essential to urinate immediately before administration, as a moist urethra helps the pellet dissolve.
2. 2Insertion: While sitting or standing, stretch the penis to its full length and insert the applicator stem into the urethra. Depress the button to release the pellet.
3. 3Absorption: Roll the penis between your hands for 30 to 60 seconds to ensure the medication is evenly distributed.

For ED, Alprostadil is used on an as-needed basis. If you miss a planned use, there is no need to 'make up' the dose. For neonates, Alprostadil is a continuous infusion; if the infusion is interrupted, it is a medical emergency and must be restarted immediately by hospital staff.

In adults, an overdose of Alprostadil usually manifests as priapism (a painful erection lasting longer than 4 hours). This requires immediate medical intervention to prevent permanent tissue damage. In neonates, overdose symptoms include apnea (stopped breathing), bradycardia (slow heart rate), and severe hypotension (low blood pressure). If an overdose is suspected, the infusion must be slowed or stopped immediately, and supportive care initiated.

> Important: Follow your healthcare provider's dosing instructions. Do not adjust your dose without medical guidance.

The most frequently reported side effects of Alprostadil are localized to the site of administration.

• Penile Pain: Occurring in approximately 30% of injection users and 10-20% of suppository users, this is often described as a dull ache or a burning sensation in the penis or groin area. It typically subsides as the drug is metabolized.
• Urethral Burning: Common with the MUSE pellet, this sensation occurs during or shortly after insertion.
• Minor Bleeding or Bruising: Small spots of blood or a 'black and blue' mark at the injection site are common, especially if pressure is not applied correctly after the needle is withdrawn.

Alprostadil is a potent vasodilator that requires careful administration. Patients using the injection or suppository forms for ED must be trained by a healthcare professional on the correct technique. Improper injection can lead to permanent injury. Furthermore, Alprostadil does not protect against sexually transmitted infections (STIs), including HIV; appropriate barrier methods should still be used.

No FDA black box warnings for Alprostadil. However, clinical guidelines emphasize that Alprostadil should only be used in settings where emergency resuscitation (for neonates) or urological intervention (for priapism) is readily available.

• Priapism Risk: Patients with conditions that predispose them to priapism, such as sickle cell anemia, multiple myeloma, or leukemia, must use Alprostadil with extreme caution, as the risk of a prolonged erection is significantly higher.

• Other ED Medications: Alprostadil should not be used in combination with other erectile dysfunction treatments, such as oral PDE5 inhibitors (Sildenafil, Tadalafil, Vardenafil) or other injectable agents (like Trimix, unless specifically directed by a specialist). Combining these can lead to an extremely high risk of priapism and severe hypotension.
• Nitrates: While the interaction is less severe than with oral ED drugs, using Alprostadil with nitrates (e.g., nitroglycerin for chest pain) can cause an additive vasodilatory effect, leading to dangerously low blood pressure.

• Antihypertensives (Blood Pressure Meds): Alprostadil may enhance the effects of medications used to treat high blood pressure (e.g., beta-blockers, ACE inhibitors, diuretics). This can result in increased dizziness or fainting. Patients should be cautious when starting Alprostadil if they are already on a multi-drug regimen for hypertension.

Alprostadil must NEVER be used in the following circumstances:

1. 1Predisposition to Priapism: Patients with sickle cell anemia or trait, multiple myeloma, or leukemia are at a high risk for prolonged, painful erections that can cause permanent damage.
2. 2Anatomical Deformities of the Penis: Conditions such as angulation, cavernosal fibrosis, or Peyronie's disease make the use of injections or suppositories dangerous and potentially ineffective.
3. 3Penile Implants: Alprostadil should not be used in men who have a functional or non-functional penile prosthesis.
4. 4Hypersensitivity

FDA Pregnancy Category: X (for ED use) / Category C (for neonatal use).

Alprostadil is not indicated for use in women. However, it is known that Alprostadil is present in the semen of men using the drug. While the amounts are small, Alprostadil can cause uterine contractions. Therefore, if a man uses Alprostadil while his partner is pregnant, a condom MUST be used to prevent the medication from coming into contact with the woman's vagina and potentially causing premature labor or miscarriage.

It is not known if Alprostadil is excreted in human milk. Since the drug is not indicated for use in nursing mothers, and its half-life is extremely short, the risk to a nursing infant from a father's use of the medication is non-existent. For the neonates receiving the drug directly, breastfeeding is usually paused in favor of controlled IV nutrition and monitoring in the NICU.

Alprostadil is a 'standard of care' medication for neonates with ductal-dependent congenital heart defects. It is approved for use from birth. The primary concern in this population is apnea

Alprostadil is a synthetic form of Prostaglandin E1 (PGE1). Its primary molecular mechanism involves binding to EP (E-prostanoid) receptors, specifically the EP2 and EP4 subtypes, which are coupled to the Gs protein. This binding stimulates the enzyme adenylate cyclase, increasing the production of cyclic AMP (cAMP).

In smooth muscle cells, elevated cAMP levels activate protein kinase A (PKA), which leads to the phosphorylation of proteins that regulate calcium channels. The end result is a decrease in intracellular calcium and the relaxation of smooth muscle. In the penis, this allows for arterial dilation and engorgement. In the neonate, this prevents the muscular wall of the ductus arteriosus from contracting and closing.

• Onset of Action: For ED, an erection typically begins within 5 to 20 minutes after administration. In neonates, improvements in blood oxygenation are usually seen within 15 to 30 minutes of starting the infusion.