Interactions

Interactions with Drugs

Evening primrose oil may lower blood sugar levels. Caution is advised when using medications that may also lower blood sugar. People taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.

Evening primrose oil may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants ("blood thinners") such as warfarin (Coumadin®) or heparin, anti-platelet drugs such as clopidogrel (Plavix®), and non-steroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).

Evening primrose oil may interfere with the way the body processes certain drugs using the liver's "cytochrome P450" enzyme system. As a result, the levels of these drugs may be increased in the blood, and may cause increased effects or potentially serious adverse reactions. People using any medications should check the package insert, and speak with a qualified healthcare professional, including a pharmacist, about possible interactions.

Evening primrose oil may increase the amount of drowsiness caused by some drugs. Examples include benzodiazepines such as lorazepam (Ativan®) or diazepam (Valium®), barbiturates such as phenobarbital, narcotics such as codeine, some antidepressants, and alcohol. Caution is advised while driving or operating machinery.

Evening primrose oil may cause low blood pressure. Caution is advised in people taking drugs that lower blood pressure.

Evening primrose oil may also interact with agents for arthritis, cancer, or obesity; agents for the brain, skin, stomach, or intestines; agents that lower cholesterol; alcohol; aldose reductase inhibitors; anesthetics; antibiotics; anticonvulsants; antidepressant agents such as monoamine oxidase inhibitors (MAOIs) or selective serotonin reuptake inhibitors (SSRIs); anti-inflammatory agents; antipsychotics; antiviral agents; beta-blockers; celecoxib; CNS depressants or stimulants; corticosteroids; COX-2 inhibitors; Faslodex®; phenothiazines; seizure threshold-lowering agents; tamoxifen; or vincristine.

Interactions with Herbs and Dietary Supplements

Evening primrose oil may alter blood sugar levels. Caution is advised when using herbs or supplements that may also alter blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.

Evening primrose oil may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.

Evening primrose oil may interfere with the way the body processes certain herbs or supplements using the liver's "cytochrome P450" enzyme system. As a result, the levels of other herbs or supplements may become too high in the blood. It may also alter the effects that other herbs or supplements possibly have on the P450 system.

Evening primrose oil may increase the amount of drowsiness caused by some herbs or supplements.

Evening primrose oil may cause altered blood pressure. Caution is advised in people taking herbs or supplements that alter blood pressure.

Evening primrose oil may also interact with anesthetics; antibacterials; anticonvulsants; antidepressants such as monoamine oxidase inhibitors (MAOIs) or selective serotonin reuptake inhibitors (SSRIs); anti-inflammatories; antioxidants; antipsychotics; antivirals; CNS depressants or stimulants; COX inhibitors; herbs and supplements for arthritis, cancer, or obesity; herbs and supplements for the brain, skin, stomach, or intestines; herbs and supplements that reduce cholesterol; seizure threshold-lowering herbs and supplements; thyme; vitamin C; zinc.

This evidence-based monograph was prepared by The Natural Standard Research Collaboration

www.naturalstandard.com