Sildenafil 20 mg genericGeneric drugs usually cost less than the brand-name version. Some medications lower blood pressure and each of these medications, Viagra, Sildenafil, Levitra, or Cialis, can add to that blood pressure lowering effect and be quite dangerous.
Dosage of sildenafil citrate 100mgHowever, it can have a serious interaction with nitrates. It should be taken 30 minutes to an hour before it is needed, but can be taken up to 4 hours before it is needed. However, Levitra is available at a lower dose and commonly causes dizziness.