Sildenafil vs Tadalafil: what is the difference?
Sildenafil and tadalafil are both PDE5 inhibitors, but sildenafil acts for about four to six hours while tadalafil's effect can span a day and a half.
Sources and notes
- The sentence under the titlefrom sourceMoleculeFinder comparison notesThe pair's answer line.
- The two drawingscomputedMoleculeFinder rule (RDKit MCS)Each molecule's own drawing, as its page shows it. The common core, 7 of 33 atoms, is too small to align on.
Side by side
| Sildenafil | Tadalafil | |
|---|---|---|
| Molecular weightCalculated PubChem | 474.6 g/molC22H30N6O4S | 389.4 g/molC22H19N3O4 |
| Hydrogen-bond donorsCalculated PubChem | 1 | 1 |
| FamilyEditorial MoleculeFinder curated | Pde5 inhibitor | Pde5 inhibitor |
| Everyday groupEditorial MoleculeFinder curated | Prescription medicine | Prescription medicine |
| Chemical groupsCalculated Found by rule (RDKit) | Aromatics, Ethers | Aromatics, Amides, Ethers |
| Hazard labelReported ECHA, HSDB via PubChem; ECHA via PubChem | Warning | Warning |
| The supplier-filed hazard label's signal word, not a statement about ordinary use. | ||
Sources and notes
- Molecular weightcomputedPubChemComputed from the structure; the formula is under each weight.
- Hydrogen-bond donorscomputedPubChemThe hydrogens on nitrogen or oxygen that each molecule can lend to a hydrogen bond, counted from its structure.
- Familyfrom sourceMoleculeFinder curated
- Everyday groupfrom sourceMoleculeFinder curated
- Chemical groupscomputedFound by rule (RDKit)Each group is found in the structure by a chemical pattern.
- Hazard labelfrom sourceECHA, HSDB via PubChem; ECHA via PubChem
- ECHAfrom sourceAttributionSource: European Chemicals Agency, echa.europa.eu.
- Identifiersfrom sourcePubChemPubChem CID 135398744 (Sildenafil) and 110635 (Tadalafil).
In more detail
Both keep cyclic GMP from being broken down so blood vessels stay relaxed. Sildenafil acts for roughly four to six hours; tadalafil's half-life is around 17.5 hours and its effect can span a day and a half, which is why it acquired the weekend nickname. Sildenafil is the more affected by a fatty meal, which slows its absorption, and tadalafil much less so. Their side effect profiles follow their off-target selectivity: sildenafil has some activity at PDE6 in the retina, which produces the occasional blue tinge to vision, while tadalafil has more at PDE11, which is associated with back and muscle ache. Both were developed for cardiovascular indications before their current ones and both remain in use for pulmonary hypertension.
Sources and notes
- The paragraphfrom sourceMoleculeFinder comparison notes
Questions
- What is the difference between Sildenafil and Tadalafil?
- Sildenafil and tadalafil are both PDE5 inhibitors, but sildenafil acts for about four to six hours while tadalafil's effect can span a day and a half.
- Is Sildenafil bigger than Tadalafil?
- Sildenafil is the heavier molecule, 474.6 g/mol against 389.4 g/mol for Tadalafil. Sildenafil is C22H30N6O4S and Tadalafil is C22H19N3O4.
Sources and notes
- The answersfrom sourceMoleculeFinderThe first is the pair's answer line; the others are read off the table above.