Clinical Management and Pharmacotherapy for Erectile Dysfunction and PE

Premature Ejaculation (PE) Management

Dapoxetine (Priligy)

Dapoxetine is a selective serotonin reuptake inhibitor (SSRI) that modulates the ejaculatory reflex.

Dosing and Administration

• Dose: 30 mg, taken 1–3 hours before anticipated intercourse.
• Maximum Frequency: One dose per 24 hours.

Side Effects

• Dizziness
• Vomiting
• Fainting (Syncope)
• Hypotension

Contraindications

• Significant cardiac conditions.
• Hepatic impairment.
• Renal impairment.
• Concomitant use with antidepressants or drugs that may cause serotonin toxicity.
• Concomitant use with strong CYP3A4 inhibitors.

Alternative PE Treatment

Local anesthetics have also been used effectively to manage premature ejaculation.

Phosphodiesterase Type 5 (PDE5) Inhibitors

Common Side Effects of PDE5 Inhibitors

• Headache: Tadalafil-induced headaches typically last longer (3–8 hours).
• Dizziness: Less common with Avanafil.
• Flushing.
• Dyspepsia (Indigestion): Less common with Avanafil.
• Nasal congestion or rhinitis.
• Back/Muscle Pain (Myalgia): More common with Tadalafil.

Contraindications for PDE5 Inhibitors

• Myocardial infarction, stroke, or life-threatening arrhythmias within the last 6 months.
• Hypotension (Blood Pressure < 90/50 mmHg).
• Unstable angina.
• Hypertrophic cardiomyopathy.
• Severe hepatic and renal impairment.
• Degenerative retinal disorders and Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION).

Drug-Drug Interactions with PDE5 Inhibitors

• Nitrates: Risk of profound hypotension, syncope, cardiac arrest, and death. Strict spacing is required:
  • Avanafil: At least 12 hours.
  • Sildenafil and Vardenafil: At least 24 hours.
  • Tadalafil: 48 hours (or potentially longer).
• Anti-hypertensives: Especially alpha-blockers, due to risk of additive hypotension.
• Anti-arrhythmic Agents: Vardenafil specifically can prolong the QT interval.
• CYP3A4 Inhibitors: May necessitate dose reduction or be an absolute contraindication, depending on the specific PDE5 inhibitor and inhibitor strength.

Erectile Dysfunction (ED) Diagnosis

1. Patient History

   Assessment of secondary ED causes, drug-induced ED, and the nature of sexual function (libido, erection quality, ejaculation, and orgasms).

2. Physical Examination

   Evaluation for:

   • Nervous system issues.
   • Hormonal problems (assessing secondary sexual characteristics).
   • Anatomical problems (e.g., penile bending indicative of Peyronie’s disease).
   • Circulatory problems.

3. Laboratory Tests

   Standard tests include:

   • Complete Blood Count (CBC): Anemia may cause fatigue leading to ED.
   • Liver and kidney function tests.
   • Thyroid function test.
   • Hormone levels (Testosterone and Prolactin).
   • Urine analysis (checking for sugar, protein, and testosterone).

4. Nocturnal Penile Tumescence (Sleep Erections)

   If nocturnal erections do not occur, organic erectile dysfunction is more probable than psychological causes.

5. Psychological Examination

Medications Causing Erectile Dysfunction

• Antihypertensives: Thiazide diuretics, beta-blockers, clonidine, methyldopa (these can decrease penile blood flow).
• Anticholinergics: Antihistamines.
• Antidepressants: SSRIs, TCAs, MAOIs.
• Antipsychotics: Including Lithium.
• CNS Depressants: Benzodiazepines, ethanol, opioids.
• Anticonvulsants.
• Anti-androgens and Hormones: 5α-reductase inhibitors, progesterone, estrogen, and cimetidine.
• Drugs of Abuse: Marijuana.

Key Risk Factors for Erectile Dysfunction

• Depression.
• Dyslipidemia.
• Diabetes Mellitus.
• Hypertension.
• Neurovascular disease.
• Obstructive sleep apnea.
• Smoking (causes altered penile hemodynamics).
• Alcohol consumption.
• Medications (up to 25% of ED cases may be drug-related).
• Pelvic radiation (leading to stenosis of pelvic arteries).
• Trauma (e.g., pelvic fractures, spinal cord injuries).