Yes, Cialis Interacts Dangerously with Nitrates
Cialis (tadalafil) causes a severe drop in blood pressure when combined with nitrates, used for chest pain or heart conditions like angina. This interaction can lead to life-threatening hypotension, fainting, heart attack, or stroke. The FDA warns against using them together and advises waiting at least 48 hours after the last Cialis dose before taking nitrates.[1][2]
How the Interaction Works
Both Cialis, a PDE5 inhibitor, and nitrates (e.g., nitroglycerin, isosorbide dinitrate) relax blood vessels. Together, they amplify vasodilation, slashing blood pressure. Even topical nitrates or long-acting forms pose the same risk. Emergency nitrates during a heart attack are especially hazardous after Cialis.[1][3]
Which Nitrates Are Involved
- Short-acting: Sublingual nitroglycerin.
- Long-acting: Isosorbide mononitrate, isosorbide dinitrate.
- Others: Recreational "poppers" (amyl nitrite), nitric oxide donors like riociguat (Adempas).[1][2]
What Patients Should Do
Consult a doctor before starting Cialis if you use nitrates or have heart issues. Do not take them within 48 hours of Cialis. If chest pain hits, call emergency services first—do not self-administer nitrates. Alternatives like alprostadil injections may suit nitrate users.[2][3]
Comparison with Viagra and Levitra
All PDE5 inhibitors (Viagra/sildenafil, Levitra/vardenafil, Cialis) ban nitrates, but timelines differ: 24 hours for Viagra/Levitra, 48 for Cialis due to its longer half-life (17.5 hours).[1][3]
Sources
[1]: FDA Cialis Label
[2]: Mayo Clinic: Tadalafil Interactions
[3]: Drugs.com: Cialis-Nitrate Interaction