Cialis (tadalafil) can work for up to 36 hours. It can help maintain your erection even after ejaculation.
If an erection lasts for longer than 4 hours, seek immediate emergency medical care as this can lead to permanent damage.
Cialis (tadalafil) is known for its long duration of action, especially compared to other erectile dysfunction (ED) medications like Viagra (sildenafil).
? Duration of Cialis
✅ Effect Duration: Up to 36 Hours
- Often called “the weekend pill” because one dose can remain effective for up to 36 hours.
- This does not mean a continuous erection for 36 hours — it means enhanced erectile response can occur any time within that window, only with sexual stimulation.
? Why It Lasts So Long: Pharmacokinetics
| Property | Cialis (Tadalafil) |
|---|---|
| Onset of Action | 30 to 60 minutes |
| Time to Peak Plasma Level | ~2 hours |
| Half-Life | ~17.5 hours |
| Duration of Action | Up to 36 hours |
| Absorption Affected by Food? | No (unlike Viagra) |
The long half-life is the key reason Cialis lasts longer than other PDE5 inhibitors.
? Two Dosing Options
1. As-Needed Dosing (10 or 20 mg)
- Taken 30–60 minutes before sexual activity.
- Effects may last up to 36 hours.
2. Daily Low-Dose Dosing (2.5 or 5 mg)
- Taken once daily, regardless of timing of sexual activity.
- Allows for spontaneous sex at any time.
- Ideal for men with regular sexual activity (≥2x/week).
⚠️ Important Considerations
- Sexual stimulation is required: Cialis doesn’t cause spontaneous erections.
- Avoid with nitrates (like nitroglycerin): Can cause life-threatening hypotension.
- Dose adjustments may be needed:
- Liver or kidney impairment
- Use with CYP3A4 inhibitors (e.g., ketoconazole, ritonavir)
? Summary
| Feature | Cialis |
|---|---|
| Onset | 30–60 minutes |
| Duration | Up to 36 hours |
| Half-life | ~17.5 hours |
| Food interaction | Minimal |
| Daily version available? | Yes (2.5 or 5 mg) |
| Brand name | Cialis; also approved as Adcirca (for PAH) |