Understanding PDE5 Inhibitors
Erectile dysfunction medications like sildenafil (Viagra) and tadalafil (Cialis) belong to a class called PDE5 inhibitors.
The Mechanism
During arousal, your body releases nitric oxide, which triggers a chain reaction:
- Nitric oxide relaxes smooth muscle in penile blood vessels
- cGMP (a signaling molecule) accumulates, increasing blood flow
- PDE5 enzymes naturally break down cGMP over time
PDE5 inhibitors block step 3, allowing cGMP to persist longer and maintain blood flow.
Key Differences Between Medications
| Medication | Onset | Duration | Take With Food? | |-----------|-------|----------|----------------| | Sildenafil | 30–60 min | 4–6 hours | Avoid heavy meals | | Tadalafil (daily) | Continuous | 24–36 hours | Yes | | Tadalafil (as needed) | 30 min | 24–36 hours | Yes |
What They Don't Do
These medications require arousal to work — they don't create spontaneous erections. They also don't increase libido or treat underlying hormonal issues.
"PDE5 inhibitors are remarkably effective for most men, but the right choice depends on your lifestyle and preferences." — Dr. James Rivera, Urologist