See the DrugPatentWatch profile for cialis
Is it safe to take Cialis (tadalafil) and Viagra (sildenafil) on the same day?
In general, you should not take Cialis and Viagra together unless your clinician specifically tells you to do so. Both drugs are in the same class (PDE5 inhibitors) and they can both lower blood pressure and increase side effects. Taking both at once raises the risk without reliably doubling benefit for most people.
What can happen if you combine them?
Combining PDE5 inhibitors can increase side effects such as:
- Dizziness or fainting from low blood pressure
- Headache, flushing, nasal congestion
- Stomach upset
- Abnormal vision changes or other class-related effects
The biggest safety concern is potentially excessive blood pressure lowering, especially if you take other blood-pressure-lowering medicines.
How do the dosing “windows” compare (why the timing matters)?
- Viagra (sildenafil) is typically dosed once per day for erectile dysfunction, with effects that can last several hours.
- Cialis (tadalafil) lasts much longer (often up to 24–36 hours), which is why it’s sometimes prescribed daily.
Because Cialis’s effects linger, adding Viagra on top can mean you are still under the influence of the first medication when you take the second.
What about nitrates—why that combination is an emergency?
You must not use Cialis or Viagra with nitrates (for example, nitroglycerin) or “poppers” (amyl nitrite/amyl nitrite-type drugs). That combination can cause a dangerous drop in blood pressure. If you ever get chest pain while using a PDE5 inhibitor, seek emergency care and tell responders what you took.
What if you already took one—should you take the other?
If you’ve already taken Cialis or Viagra, it’s safest to wait and not take the other dose unless your prescriber instructs you to. If you feel lightheaded, dizzy, or unwell after taking either, get medical advice urgently.
When might a doctor use both?
Some clinicians may consider a strategy in very specific circumstances (for example, changing regimens or switching medications rather than using both simultaneously). But routine “stacking” of Cialis + Viagra is usually avoided.
Better next steps
- Talk with the prescriber or pharmacist about the best single option for you (Cialis vs Viagra) and your starting dose.
- Review all your other medications, especially blood pressure drugs and nitrates.
- If ED meds aren’t working or side effects are happening, don’t adjust by combining them—ask about dose changes, timing, or alternatives.
If you tell me your doses (mg), when you took the first pill, and any other medicines (especially nitrates or blood pressure meds), I can help you understand the risk more specifically.