Interactions

Possible interactions include:

• Anticoagulants and anti-platelet drugs, herbs and supplements. These types of drugs, herbs and supplements reduce blood clotting. Combining oral use of evening primrose oil with them might increase the risk of bleeding.
• Cytochrome P450 3A4 (CYP3A4) substrates. Use evening primrose cautiously if you're taking a drug affected by these enzymes, such as lovastatin (Altoprev).
• Lopinavir and ritonavir (Kaletra). This combined medication is used in the treatment of the infection caused by the human immunodeficiency virus (HIV). Evening primrose oil might slow down how quickly this medication is broken down in the body.
• Phenothiazines. Taking evening primrose oil with these drugs used to treat serious mental and emotional disorders might increase risk of seizures in some people.