Your doctor may adjust your dose as needed. Grapefruit Juice Using this medicine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive. Common side effects may include: headache; flushing warmth, redness, or tingly feeling ; nausea, upset stomach; runny or stuffy nose; or muscle pain, back pain, pain in your arms, legs, or back. They include dutasteride Avodart, Jalyn and finasteride Propecia, Proscar. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines. Kidney disease, mild or moderate or Liver disease, mild or moderate—Use with caution.Tadalafil (Cialis) is taken by mouth either as needed before sexual activity or once daily for erectile dysfunction (ED).It’s also taken once daily to treat symptoms from an enlarged prostate (benign prostatic hyperplasia, or BPH).Tadalafil (Cialis) is available both as brand-name and generic tablets. Common side effects of this medication include . Tadalafil is a medicine used to treat erectile dysfunction (ED, also called impotence) and problems with urination caused by an enlarged prostate (benign prostatic hypertrophy or BPH). It is sometimes known by its generic name tadalafil, and sometimes known by its trade name, Cialis. There are also other brands of this medicine available. Tadalafil (Cialis). This medication is taken with or without food an hour before sex. It works for up to 36 hours. You can take it in a small dose daily or in a larger dose as needed. Avanafil (Stendra). You can take this medicine with or without food 30 minutes before sex, depending on the dose.