Short answer: Both are PDE5 inhibitor tablets for erectile dysfunction.12 Stendra (avanafil) is taken only as needed, as early as about 15 minutes before sex, starting at 100 mg. Cialis (tadalafil) is taken as needed, starting at 10 mg, or once daily at 2.5 to 5 mg, and is also approved for BPH. Neither may be used with nitrates. Neither has a boxed warning or reports a trial against the other.
| Stendra | Cialis | |
|---|---|---|
| Drug | Avanafil1 | Tadalafil2 |
| Approved for | Erectile dysfunction in adult males1 | Erectile dysfunction, symptoms of BPH, and both together2 |
| How taken | As needed only, at most once a day1 | As needed, at most once a day in most patients, or once daily at about the same time2 |
| Doses | Start 100 mg; 50 mg or 200 mg1 | As needed: start 10 mg, 5 to 20 mg. Once daily: 2.5 or 5 mg for ED, 5 mg for BPH2 |
| Timing before sex | 100 or 200 mg as early as about 15 minutes before; 50 mg about 30 minutes before1 | As needed: at least 30 minutes before; improved erections for up to 36 hours2 |
| Nitrate in an emergency | At least 12 hours after the last dose1 | At least 48 hours after the last dose2 |
| Side effects in label trials | As needed: headache 5.1% to 10.5% vs 1.7% on placebo, flushing 3.2% to 4.3% vs 0.0%1 | As needed: headache 11% to 15% vs 5% on placebo, indigestion 4% to 10% vs 1%, back pain 3% to 6% vs 3%2 |
| Boxed warning | None1 | None2 |
Mostly. Both labels say not to use them with any nitrate or with riociguat, and both warn about heart risk during sex, erections lasting more than 4 hours, sudden vision loss, sudden hearing loss, added blood pressure lowering with alpha-blockers, and heavy alcohol use.12 With strong CYP3A4 inhibitors such as ketoconazole or ritonavir, Stendra is not used, while Cialis is capped at 10 mg once every 72 hours as needed or 2.5 mg daily.12 The Cialis label notes back pain and muscle aches usually start 12 to 24 hours after a dose.2 These numbers come from separate trials with different people, lengths and methods, so they are not a head-to-head comparison.
Which, if either, fits is for your prescriber. More detail: Stendra side effects, Cialis side effects, the Stendra and Cialis dosing schedules, the Cialis missed-dose page, Stendra vs Viagra: how do avanafil and sildenafil differ? and Cialis daily vs as needed: how do the two tadalafil schedules differ?.