Partial
Mostly Aligned
Patient Risk:
Low
Summary
Overall partial alignment. The claims align with label content on PDE5 inhibition (12.1) and nitrate/alpha-blocker interaction warnings, but many statements are not supported by the label (e.g., PAH indication, specific BP changes, cross-PDE5 inhibitor comparisons). Several assertions are not present in the FDA-approved label and constitute off-label or incorrect interpretations.
Category Scores
Accurate Statements
Viagra inhibits phosphodiesterase type 5 (PDE5), increasing cyclic GMP levels.
12.1: Sildenafil inhibits PDE5, increasing cGMP.
Unsupported Statements
Viagra does not raise blood pressure.
Label does not state that blood pressure is not raised; BP changes and nitrates interactions are described.
Viagra lowers blood pressure by relaxing blood vessels.
Label describes PDE5 inhibition leading to increased cGMP and smooth muscle relaxation in erectile tissue; does not generalize to lowering BP.
Viagra treats erectile dysfunction and pulmonary hypertension.
ED indication is in Vi agra label; PAH indication is for Revatio, not Viagra.
This relaxes smooth muscle in blood vessel walls, dilating arteries and veins.
Label discusses smooth muscle relaxation in the corpus cavernosum; does not state a general vascular relaxation across all vessels.
The result is a modest drop in systolic blood pressure—typically 8-10 mmHg and diastolic 5-6 mmHg—lasting 1-2 hours after a 50mg dose in healthy men.
No explicit numerical blood pressure change is provided in the label.
Effects are similar across doses but stronger when combined with other vasodilators.
Label does not provide dose-by-dose BP effects or additive vasodilator interactions beyond specific drug interactions.
Unlike stimulants or decongestants that constrict vessels and elevate pressure, Viagra's mechanism promotes vasodilation.
Label does not compare Viagra to stimulants/decongestants.
Clinical trials confirm no hypertensive effects.
Label notes BP effects and nitrate interactions; does not state no hypertensive effects.
It reduces pulmonary artery pressure by 20-30% in pulmonary hypertension patients.
PAH indication is not part of Viagra labeling; PAH data are in Revatio.
Viagra is safe for most with hypertension if managed.
Label does not provide a general safety statement for hypertensive patients.
It can amplify drops when taken with nitrates (e.g., nitroglycerin), risking severe hypotension, fainting, or heart attack.
This interaction is described as a risk in the label and is correctly supported.
Alpha-blockers like tamsulosin also heighten this risk.
Label cautions about additive hypotension with alpha-blockers.
Doctors advise spacing doses or avoiding combinations.
Dosing and interaction precautions are described in the label.
Blood pressure should be monitored post-dose.
No explicit BP monitoring guidance in the Viagra label.
All PDE5 inhibitors (Cialis/tadalafil, Levitra/vardenafil) lower blood pressure similarly, with no elevation risk.
Label addresses sildenafil-specific interactions; no cross-PDE5 inhibitor comparison stated.
Cialis has a longer half-life (17-36 hours), prolonging effects.
Pharmacokinetics of tadalafil are not described in the Viagra label.
Levitra acts faster but fades quicker.
Levitra (vardenafil) specifics are not described in the Viagra label.
Rare cases report transient increases in blood pressure due to sexual activity itself, anxiety, or unrelated factors—not the drug.
Not a stated label claim.
Consult a doctor if pressure spikes occur.
No such instruction on BP spikes in the Viagra label.
Contradictions
Important Omissions
Pulmonary arterial hypertension indication for sildenafil is not listed in Viagra label; PAH use is Revatio.
Importance:
High
No explicit numerical BP change data or dosing-specific BP effects in label.
Importance:
Moderate
Safety Assessment
Potential Patient Risk:
Low
Major risk stems from concomitant nitrates or alpha-blockers; otherwise general BP effects are not described as universally hypertensive.
Regulatory Assessment
| On Label |
No |
| Off-label Discussion |
Yes |
| Promotes Unapproved Use |
No |
| Hallucination Risk |
Low |
Recommendation
Mostly Aligned
Primary Issue
PAH indication and several BP-related claims are not label-supported.
Suggested Improvement
Restrict statements to FDA-approved indications and labeled pharmacology; remove off-label assertions (e.g., PAH use, specific numerical BP changes). Cite exact sections (Indications 1, 12.1, 4, 5, 7) and align with the labeled dosing and counseling content.