Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. For further information contact your pharmacist or Eli Lilly and Company directly. Swallow it whole. It may not be safe to breastfeed while using this medicine. Physicians should discuss with patients the potential for CIALIS to augment the blood-pressure-lowering effect of alpha-blockers and antihypertensive medications.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. For most individuals, the recommended starting dose of tadalafil is 10 mg per day taken before sexual activity (tadalafil for use as needed). Depending on the adequacy of the response or side effects, the dose may be increased to 20 mg or decreased to 5 mg a day. The effect of tadalafil may last up to 36 hours. CIALIS is indicated for the treatment of ED and the signs and symptoms of BPH (ED/BPH). Limitation of Use If CIALIS is used with finasteride to initiate BPH treatment, such use is recommended for up to 26 weeks because the incremental benefit of CIALIS decreases from 4 weeks until 26 weeks, and the incremental benefit of CIALIS beyond.