Cialis vs. Sildenafil
See how Cialis and Sildenafil compare on approved uses, dosing, side effects, and cost.
Key Takeaways
Cialis and sildenafil are both PDE5 inhibitors for erectile dysfunction, but Cialis lasts up to 36 hours while sildenafil works for about 4 to 6 hours.
Cialis is also FDA-approved for daily use in benign prostatic hyperplasia, while sildenafil is FDA-approved for pulmonary arterial hypertension under the Revatio brand.
Both drugs can cause headache, dyspepsia, and nasal congestion, but sildenafil has the longer track record, having been approved in 1998, five years before Cialis.
Cialis vs. Sildenafil Drug Summary
Cialis
Cialis (tadalafil) is a PDE5 inhibitor used to treat erectile dysfunction and benign prostatic hyperplasia (BPH), sometimes both together. It comes as an oral tablet that can be taken daily in a low dose or as needed in a higher dose before sexual activity.
Sildenafil
Sildenafil is a PDE5 inhibitor used to treat erectile dysfunction, taken as an oral tablet only as needed before sexual activity. Under the brand name Revatio, sildenafil is also FDA-approved to treat pulmonary arterial hypertension.
Cialis vs. Sildenafil Side Effects
Cialis
Sildenafil
Cialis vs. Sildenafil Dosage
Cialis
Sildenafil
| STAGE | DOSE | WHEN |
| Starting dose | 2.5 mg once daily | At the start |
| Maximum dose | 20 mg as needed | If needed |
| Dose changes | 3 increases | As tolerated |
| STAGE | DOSE | WHEN |
| Starting dose | 25 mg as needed | At the start |
| Maximum dose | 100 mg as needed | If needed |
| Dose changes | 2 increases | As tolerated |
Cialis
| STAGE | DOSE | WHEN |
| Starting dose | 2.5 mg once daily | At the start |
| Maximum dose | 20 mg as needed | If needed |
| Dose changes | 3 increases | As tolerated |
Sildenafil
| STAGE | DOSE | WHEN |
| Starting dose | 25 mg as needed | At the start |
| Maximum dose | 100 mg as needed | If needed |
| Dose changes | 2 increases | As tolerated |
Cialis vs. Sildenafil Indications
Cialis
Cialis treats erectile dysfunction and the urinary symptoms of benign prostatic hyperplasia, and it is the only PDE5 inhibitor approved to treat both conditions together with one daily dose. It is sometimes used off-label, under the brand name Adcirca, for pulmonary arterial hypertension.
Erectile dysfunction
Benign prostatic hyperplasia (BPH) symptoms
Combined ED and BPH symptoms
Off-label: pulmonary arterial hypertension (as Adcirca)
Sildenafil
Sildenafil treats erectile dysfunction and is FDA-approved under the brand name Revatio for pulmonary arterial hypertension. It is also used off-label for conditions like Raynaud's phenomenon and female sexual arousal disorder.
Erectile dysfunction
Pulmonary arterial hypertension (as Revatio)
Off-label: Raynaud's phenomenon
Off-label: female sexual arousal disorder
Cialis vs. Sildenafil Pros and Cons
Cialis
Cialis stands out for its long 36-hour window, which gives more flexibility around timing sexual activity, and for being the only PDE5 inhibitor approved for daily dosing in both ED and BPH. It requires attention to alpha-blocker interactions and, for daily use, consistent adherence.
Pros
Lasts up to 36 hours, longer than sildenafil's window
Only PDE5 inhibitor with a daily-dose option for ED and BPH together
Approved specifically for combined ED and BPH symptoms
Less need to plan dosing around a specific moment
Cons
Longer half-life means side effects may linger longer if they occur
Not recommended with alpha-blockers other than tamsulosin
No low-dose 25 mg as-needed option for occasional use
Off-label pulmonary hypertension use requires the separate Adcirca brand
Sildenafil
Sildenafil has the longest track record of any PDE5 inhibitor and offers flexible as-needed dosing from 25 mg to 100 mg. It works for a shorter window than Cialis, so timing before sexual activity matters more.
Pros
Longest safety track record, approved since 1998
Also FDA-approved for pulmonary arterial hypertension (as Revatio)
Flexible as-needed dosing from 25 mg to 100 mg
No boxed warning on the label
Cons
Shorter duration of action requires timing around activity
Only available as needed, with no daily-use option
Label specifically notes risk of sudden vision or hearing loss
Best effect requires dosing about an hour beforehand
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