Tadalafil may cause side effects. If you are taking tadalafil for erectile dysfunction on a regular schedule, take the missed dose as soon as you remember it. Therefore the use of such treatments in combination with Cialis is not recommended. John’s wort. Tadalafil comes as a tablet to take by mouth. Tell your doctor if any of these symptoms are severe or do not go away: headache.AdGet a Prescription for ED treatment, discreetly deliverED to your ive Offers · How It Works · Get More Info4/5 ( reviews)Types: Finasteride · Tadalafil · Sildenafil. The 20mg dose can also be compounded at pharmacies and is generally cheaper but if you may obv have to consume/buy more pills for your dose. Cialis (20, 10, 5 and mg) . Cialis lasts up to 36 hours in the body, while Viagra lasts 4–6 hours in the body. Both are taken 30 minutes before sex. Cialis can cause limb pain, while Viagra can cause vision change, rash.