Can You Take Sildenafil and Tadalafil Together?
Short answer
Use cautionNo, not unless a doctor has specifically told you to. Sildenafil (Viagra) and tadalafil (Cialis) are both PDE5 inhibitors that work the same way. The FDA labels say the safety of combining them has not been studied, and doubling up can drop your blood pressure and increase side effects without a proven extra benefit. If one is not working well enough, talk to your prescriber about changing the dose, timing or medicine instead.
Why doubling up is risky
PDE5 inhibitors relax blood vessels, which improves blood flow to the penis. They also relax blood vessels elsewhere, which slightly lowers blood pressure. Taking two at once stacks those effects. Possible problems include:
- Dizziness or fainting from low blood pressure, especially when standing up
- Stronger headaches, flushing, nasal congestion and indigestion
- Vision changes, such as a blue tint or blurred vision
- A higher chance of an erection that lasts more than 4 hours (priapism), which is a medical emergency
How the two medicines differ
| Sildenafil (Viagra) | Tadalafil (Cialis) | |
|---|---|---|
| How long it works | About 4 hours | Up to 36 hours |
| Effect of a heavy meal | A high-fat meal can delay it | Food has little effect |
| Daily low-dose option | No | Yes, also used for an enlarged prostate |
Because tadalafil stays in your body for so long, switching from Cialis to Viagra is not as simple as waiting until the next day. Ask your prescriber how long to wait before switching.
The same two medicines are also sold under other names for pulmonary arterial hypertension (Revatio is sildenafil, Adcirca is tadalafil). If you take one of those, do not add an ED pill without your doctor’s approval.
Never combine either one with nitrates
Do not take sildenafil or tadalafil with nitrate medicines such as nitroglycerin, isosorbide mononitrate or isosorbide dinitrate, or with recreational “poppers” (amyl nitrite). The combination can cause a sudden, life-threatening drop in blood pressure. Both labels list nitrates as a contraindication.
If one is not working well enough
Before thinking about a second pill, these common issues are worth discussing with your prescriber:
- The dose may be too low, or you may need to try it several times
- Sexual stimulation is still needed for these medicines to work
- A heavy meal can slow sildenafil, and heavy drinking can make ED worse
- Low testosterone, diabetes, heart disease or medicine side effects may be involved
What the FDA labels say
Frequently asked questions
Can I take Viagra the day after Cialis?
Tadalafil can still be active for up to 36 hours and remains in your body even longer, so taking sildenafil the next day may still overlap. Ask your prescriber before switching.
Is taking both more effective?
There is no evidence that combining them works better, and the labels do not recommend it. A dose adjustment or switching to the other medicine is the usual approach.
What should I do if I accidentally took both?
Sit or lie down if you feel dizzy, avoid alcohol, and do not take more. Get emergency care for chest pain, fainting, sudden vision or hearing loss, or an erection lasting more than 4 hours.
Taking anything else?
Add all your medicines, supplements and alcohol to check every combination at once.
Sources
This page is for general education and is based on FDA labeling. It is not medical advice and does not replace a conversation with your doctor or pharmacist, who know your health history, doses and other medicines. If you think you have taken too much of a medicine, call Poison Control at 1-800-222-1222 or 911.