Can I Take Viagra (Sildenafil) and Cialis (Tadalafil) Together?

• You should not take Viagra (Sildenafil) or Cialis (Tadalafil) at the same time or on the same day
• Both medicines act in the same way, and this can increase the chance of side effects
• If either medication is not working, speak to your doctor about alternatives, or a dose increase

Viagra (Sildenafil) and Cialis (Tadalafil) are both medicines used to treat erectile dysfunction (ED) in men. They work in a similar way – by increasing blood flow to the penis – helping you to achieve and maintain an erection during sexual activity.

Because both medicines improve erections, some men wonder whether taking Viagra and Cialis together might make the effect stronger. However, doing so is not recommended and can be dangerous.

Both Viagra and Cialis belong to a group of medicines called phosphodiesterase type-5 (PDE5) inhibitors.

When taken together, the effects can overlap, causing an excessive drop in blood pressure and increasing the risk of side effects.

Taking them together can lead to:

• Dizziness or light-headedness
• Fainting or blackouts
• Rapid or irregular heartbeat
• Headache or flushing
• Chest pain or shortness of breath
• In rare cases, a dangerously prolonged erection (priapism)

Because both medicines act on the same pathway, combining them does not improve results – it only increases the risk of adverse effects.

Both medicines are highly effective, but Cialis lasts much longer, making it suitable for men who prefer spontaneity, while Viagra works for shorter, planned use.

Further reading: Tadalafil vs Sildenafil

If you take Viagra and Cialis on the same day, don’t panic, but do not take any more doses.

You may notice:

• Headache
• Flushing
• Dizziness
• Low blood pressure symptoms (feeling faint or light-headed)

Drink plenty of water, avoid alcohol, and sit or lie down if you feel dizzy. You should seek medical advice from your doctor or pharmacist.

If you experience chest pain, shortness of breath, or an erection lasting longer than 4 hours, seek urgent medical attention.

You should wait at least 24–48 hours between taking Viagra and Cialis, depending on which one you used first:

• After Viagra (Sildenafil): Wait at least 24 hours before taking Cialis.
• After Cialis (Tadalafil): Wait at least 48 hours, as Tadalafil stays in your system much longer.

Switching too soon can increase the risk of side effects and dangerously low blood pressure.

Safe alternatives to combining Viagra and Cialis

Instead of combining treatments, speak to your doctor or pharmacist about your options.

These may include:

• Adjusting the dose of one medicine (for example, increasing Sildenafil from 50mg to 100mg)
• Trying a different PDE5 inhibitor such as Vardenafil (Levitra) or Avanafil (Spedra)
• Considering daily Tadalafil (2.5mg or 5mg) for a consistent effect
• Addressing underlying causes of ED such as anxiety, lifestyle factors, or other medical conditions

Your prescriber or pharmacist can help choose the right treatment based on your needs, frequency of sexual activity, and any health conditions.

Do not take Viagra, Cialis, or any other ED medication if you:

• Take nitrates for chest pain (angina)
• Use alpha-blockers for blood pressure or prostate problems
• Have serious heart or liver conditions
• Have been advised to avoid sexual activity for medical reasons

Always speak to a doctor or pharmacist before starting or switching between ED medicines.

You should not take Viagra (Sildenafil) and Cialis (Tadalafil) together.

Both work through the same mechanism and combining them increases the risk of side effects without improving results.

If your current treatment isn’t working well enough, speak to a healthcare professional about adjusting the dose or exploring other options — never self-combine prescription medicines.

Can I take one medicine in the morning, and a different one at night?

No – you should leave a gap of around 24 hours between the two.