Erectile Dysfunction (ED) is a condition increasingly prevalent among modern men due to work pressure, psychological stress, chronic diseases (such as diabetes mellitus, cardiovascular disease, hypertension), or unhealthy lifestyle choices.
Among the current pharmacological options, the Phosphodiesterase type 5 inhibitors (PDE5 inhibitors) class is the most studied and widely utilized. These medications work to enhance blood flow to the corpus cavernosum (erectile tissue) of the penis upon sexual stimulation, thereby facilitating the achievement and maintenance of an erection.
- Mechanism of Action:
PDE5 inhibitors are considered the first-line therapy for managing Erectile Dysfunction.
- Normally, upon sexual arousal/stimulation, the body releases Nitric Oxide (NO) $\rightarrow$ this increases the concentration of cyclic Guanosine Monophosphate (cGMP) $\rightarrow$ leading to the relaxation of corpus cavernosum smooth muscle $\rightarrow$ resulting in increased penile blood flow $\rightarrow$ and an erection.
- The PDE5 enzyme is responsible for the degradation of cGMP, causing detumescence (loss of erection).
- PDE5 inhibitors block the action of the PDE5 enzyme, thus preserving cGMP levels and prolonging the ability to achieve an erection when stimulated.
Key Note: The medication does not cause a spontaneous erection; sexual desire/stimulation is required for its therapeutic effect to manifest.
- Featured Active Pharmaceutical Ingredients (APIs):
- Sildenafil
Duration of Action: 4–6 hours
Key Characteristics: Rapid onset of action ($\sim 30-60$ minutes), highly effective but commonly causes side effects like facial flushing, headache, and gastrointestinal disturbance.
- Tadalafil
Duration of Action: Extended duration (24-36 hours) (“The Weekend Pill”)
Key Characteristics: Can be taken daily at a low dose; less affected by food; suitable for individuals requiring sustained flexibility in sexual activity.
- Vardenafil
Duration of Action: 6-8 hours
Key Characteristics: Fast onset; effect similar to Sildenafil but may offer better patient tolerability in some individuals.
- Avanafil
Duration of Action: 4-6 hours
Key Characteristics: Very rapid onset (~ 15 minutes); generally associated with fewer adverse effects; considered a newer generation API.
- Advantages and Limitations of the PDE5 Inhibitor Class:
- Advantages:
- Convenient oral administration.
- High efficacy and safety profile when used correctly.
- Multiple options available to suit individual needs (short-acting, long-acting, or daily use).
- Limitations:
- Requires sexual stimulation to be effective.
- Common Adverse Drug Reactions (ADRs): facial flushing, headache, nasal congestion, dyspepsia, visual disturbances.
- Absolute Contraindication: Patients concurrently taking nitrate medications (used for cardiovascular conditions, such as angina pectoris).
- Pharmacist’s Advice
Each PDE5 inhibitor API has unique characteristics regarding its half-life, duration of action, dosing regimen, side effect profile, and patient tolerability. Therefore, there is no single “best drug,” but only the one most suitable for the individual patient.
👉 To select the correct medication, men need to receive thorough professional consultation from the specialized Pharmacists and Physicians at Men’s Health Pharmacy (Nhà thuốc Nam khoa Men’s Health). Appropriate usage ensures:
- Optimal therapeutic efficacy.
- Avoidance of dangerous drug interactions.
- Long-term protection of cardiovascular and physiological health.
Please contact or message us directly via the Fanpage:
https://www.facebook.com/nhathuocnamkhoavn of Men’s Health Pharmacy.
Address: 7B/31 Thanh Thai, Ward Dien Hong, Ho Chi Minh City, Vietnam.
Hotline: 0911 161 161.
