Keep in mind, though, that the effects for each pill vary by person and other medications you take. While Viagra and sildenafil have a life span of 4 to 6 hours, Cialis (and generic tadalafil ...

Viagra costs $90 to $139 per tablet. Generic sildenafil can range from $2 to $10 per pill, depending on the manufacturer and dose. Viagra and sildenafil are both used to treat ED, but only ...