Drug Interaction With Dilantin, Vicodin And Evening Primrose Oil

Evening primrose is a North American wildflower, the seeds of which yield an oil rich in essential fatty acids. Because these and other phytochemicals promote antioxidant and anti-inflammatory effects, evening primrose oil is used to treat diabetic neuropathy and arthritis. This medicine may interact with certain pharmaceutical drugs, however, including Dilantin and Vicodin. Check with your doctor before using this supplement if you have a chronic condition or take other medications.

Evening Primrose Pharmacology

The seeds of Oenothera biennis contain omega-6 essential fatty acids, including up to 80 percent linolenic acid, 14 percent gamma-linolenic acid, 11 percent oleic acid and 10 percent palmitic acid. In the body, gamma-linolenic acid, or GLA, undergoes enzymatic conversion into the anti-inflammatory agent prostaglandin E1. The omega-6 fatty acids in evening primrose oil such as GLA are also responsible for facilitating interactions with other medicines.

Interaction with Dilantin

Dilantin is a brand name for phenytoin, a drug used to lower the risk of specific types of seizures, including those that may occur as the result of surgical procedures affecting the brain or nervous system. The mechanism of action of this drug is to decrease electrical impulses in the brain. There is conflicting evidence regarding the potential herb-drug interaction between evening primrose oil and Dilantin, but some clinicians suspect that the gamma-linolenic acid content may interact with anti-convulsant medications like Dilantin and lower the threshold for seizures.

Interaction with Vicodin

Vicodin is a pain-relieving medication that contains a combination of acetaminophen and hydrocodone, the latter of which is a narcotic and potentially habit-forming. The acetaminophen component of this drug may increase the effects of blood-thinning drugs and interact with anti-seizure medications. This means there may be an increased risk of uncontrolled bleeding or seizure activity if Vicodin and evening primrose oil are taken together.

Other Safety Precautions

Do not use evening primrose oil during pregnancy or while nursing, or if you have a blood disorder or a history of epilepsy. Seek guidance from your physician before using this supplement if you take any other medications, including anti-coagulants such as warfarin and aspirin. Evening primrose oil may increase the effects of antidepressant drugs, including selective serotonin uptake inhibitors. Because evening primrose oil may lower blood pressure, see your doctor if you take medication to control hypertension.