Two medicines, side by side
Sildenafil vs tadalafil
Sildenafil and tadalafil are both labeled for pulmonary arterial hypertension and erectile dysfunction. Drugs@FDA records approvals of sildenafil since 1998 and of tadalafil since 2003. Pharmacies paid $0.132 per sildenafil 100 mg tablet and $0.167 per tadalafil 20 mg tablet (NADAC, October 7, 2026); the strengths differ, so the two prices are not like for like. How each works, in its label's words: Sildenafil, “The physiologic mechanism of erection of the penis involves release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation.”; Tadalafil, “Penile erection during sexual stimulation is caused by increased penile blood flow resulting from the relaxation of penile arteries and corpus cavernosal smooth muscle.”
Check it at the source: the sildenafil FDA label on DailyMed (effective November 17, 2023); the tadalafil FDA label on DailyMed (effective June 3, 2026).
Highlights of the sildenafil record
Sildenafil (Viagra) · label of November 17, 2023
Used for
From the label: indicationsVIAGRA is indicated for the treatment of erectile dysfunction. VIAGRA is a phosphodiesterase-5 (PDE5) inhibitor indicated for the treatment of erectile dysfunction (ED)
On the market
- Earliest approval on file
- March 27, 1998
- Generic labelers
- 60 labelers
- Pharmacy cost
- $0.132 per tablet
Supply and safety
- Shortage
- No current entry
- Recalls
- 2
Highlights of the tadalafil record
Tadalafil (Cialis) · label of June 3, 2026
Used for
From the label: indicationsCIALIS ® is a phosphodiesterase 5 (PDE5) inhibitor indicated for the treatment of: erectile dysfunction (ED) ( 1.1 ) the signs and symptoms of benign prostatic hyperplasia (BPH) ( 1.2 ) ED and the signs and symptoms of BPH (ED/BPH) ( 1.3 ) If CIALIS is used with finasteride to initiate BPH treatment, such use is recommended for up to 26 weeks ( 1.4 ). 1.1 Erectile Dysfunction CIALIS ® is indicated for the treatment […]
On the market
- Earliest approval on file
- November 21, 2003
- Generic labelers
- 49 labelers
- Pharmacy cost
- $0.167 per tablet
Supply and safety
- Shortage
- No current entry
- Recalls
- 12
Source: FDA drug labels via openFDA (Sildenafil label of November 17, 2023, Tadalafil label of June 3, 2026); NDC Directory, Drugs@FDA, NADAC, FDA shortages and recalls (October 8, 2026)
How do sildenafil and tadalafil differ on the record?
How each works, in its label's words: Sildenafil, “The physiologic mechanism of erection of the penis involves release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation.”; Tadalafil, “Penile erection during sexual stimulation is caused by increased penile blood flow resulting from the relaxation of penile arteries and corpus cavernosal smooth muscle.”
Both are in FDA's class phosphodiesterase 5 inhibitors.
Generics: sildenafil since 2012; tadalafil since 2018 (Drugs@FDA).
| Sildenafil | Tadalafil | |
|---|---|---|
| Labeled for | Erectile dysfunction, Pulmonary arterial hypertension | Erectile dysfunction, Enlarged prostate (BPH), Pulmonary arterial hypertension |
| Pharmacologic class | Phosphodiesterase 5 Inhibitor | Phosphodiesterase 5 Inhibitor |
| How it works (label) | The physiologic mechanism of erection of the penis involves release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation. | Penile erection during sexual stimulation is caused by increased penile blood flow resulting from the relaxation of penile arteries and corpus cavernosal smooth muscle. |
| Half-life (label) | n/a | Excretion – The mean oral clearance for tadalafil is 2.5 L/hr and the mean terminal half-life is 17.5 hours in healthy subjects. |
| Earliest approval on file (Drugs@FDA) | March 27, 1998 | November 21, 2003 |
| First generic approved | November 6, 2012 | May 22, 2018 |
| Generic labelers (NDC) | 60 labelers | 49 labelers |
| Pharmacy cost (NADAC, each one's most listed form; strengths differ) | $0.132 per tablet (Sildenafil 100 mg tablet) | $0.167 per tablet (Tadalafil 20 mg tablet) |
| 12-month price change | -11% | -19% |
| Boxed warning | No | No |
| Shortage now | No current entry | No current entry |
| Recalls recorded | 2 | 12 |
| FAERS reports (a report is not proof of cause; counts follow how widely a medicine is used) | 126,558 | 99,551 |
| DEA schedule | none | none |
Source: Drugs@FDA, FDA NDC Directory, CMS NADAC of October 7, 2026, FDA shortages and recalls, FAERS via openFDA (FDA files October 8, 2026)
What next?
- Alternatives to sildenafil
- every medicine labeled for the same conditions