All drugs (Levitra, Cialis and Viagra) work essentially the same way and have similar side effects. Levitra may work a little faster in some people and may be less sensitive to food or alcohol intake. Viagra has been around for a lot longer and has a proven safety track record

It is not safe to take Levitra, Cialis and Viagra together. You should only take one or the other. They are similar drugs, so it makes sense to try all three, on different days, and see which works best for you.
VIAGRA works in as quickly as 30 minutes and lasts for about 4 hours.

CIALIS works up to 36 hours and work in some men as fast as 30 minutes

LEVITRA is as fast as 25 minutes and its effect lasts for nearly 24 hours

If Viagra doesn't work for you, it's worth giving Cialis or Levitra a try. Each person is different, and your body may respond better to Cialis and Levitra than Viagra.

It's important to note that the maximum dose for Viagra is 100mg while the maximum dose of Levitra and Cialis is 20mg
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European officials have approved a once-daily version of impotence pill Cialis.

The drug’s maker, Eli Lilly and Co., said on Monday that the green light from the European Commission meant Cialis was the first erectile dysfunction medicine cleared for continuous use.[...]

HOW TO USE Cialis Soft Tabs

Cialis soft is placed under the tongue, where it disolves, as needed, between 15 to 20 minutes before sexual activity. Take only as directed.

PRECAUTIONS

Before using Cialis Soft Tabs, tell your doctor your medical history, including: allergies (especially drug allergies), penis conditions such as fibrosis/scarring (e.g., Peyronie's disease), history of painful/prolonged erection (priapism), sickle cell anemia, blood system cancers (such as leukemia or myeloma), eye problems (retina diseases), kidney or liver disease, bleeding disorders, active stomach ulcers, heart disease, stroke, very high or low blood pressure. Limit alcohol intake, as it may aggravate side effects of Cialis Soft. Since this softtabs may cause dizziness, caution is advised when performing tasks requiring alertness (e.g., driving). To avoid dizziness and lightheadedness when rising from a seated or lying position, get up slowly. Soft Cialis is not to be used in women or children. The elderly may be more sensitive to the side effects of Cialis soft tabs, therefore caution is advised in this group.

SIDE EFFECTS of Cialis Soft Tabs

If you experience a painful or prolonged erection (lasting longer than 4 hours), stop using this drug and seek immediate medical attention.

Headache, flushing, stomach upset, nasal stuffiness, diarrhea and dizziness might occur. If these effects persist or worsen, notify your doctor promptly. Unlikely but report promptly: painful or other urination problems, vision problems, skin rash. Very unlikely but report promptly: chest pain, fainting, foot or ankle swelling. If you notice other effects of Cialis Soft Tabs not listed above, contact your doctor or pharmacist.

OVERDOSE with Cialis Soft Tabs

If overdose is suspected, contact your local poison control center or emergency room immediately. Symptoms of overdose of Cialis Soft may include severe dizziness, fainting, or prolonged erection.[...]