Are there any known interactions with evening primrose oil or Eye Q treatment and the patients curr

Fråga: Are there any known interactions with evening primrose oil or Eye Q treatment and the patients current medication? The question concerns a patient treated with ordinary doses of propranolol (Inderal), lansoprazole (Lanzo), cyproheptadine (Periactin) and cetirizine (Zyrlex). He is now considering self-medication with Eye Q and evening primrose oil for chronic asthenic fatigue syndrome.

Sammanfattning: In general, the documentation regarding interactions between drugs and natural remedies is scarce. No interactions between Eye Q or evening primrose oil and lansoprazole, cyproheptadine or cetirizine were found in the literature. Is has been suggested that omega-3 fatty acids might amplifie the blood pressure lowering effect of propranolol in mild essential hypertension.

Svar: Evening primrose oil is a natural remedy that contains fatty acids, mainly linolenic acid and gamma-linolenic acid, from the seeds of the plant oenothera biennis. There are a wide variety of suggested indications, such as atopic eczema, mastalgia, rheumatoid arthritis, asthma, premenstrual syndrome and postviral fatigue syndrome. Evening primrose oil seems to be well tolerated, with few side effects reported (1,2).

Eye Q is a natural remedy containing the fatty acids docosahexaenoic acid, eicosapentaenoic acid from fish oil, gamma-linolenic acid from evening primrose oil and vitamin E. The amounts of the different fatty acids can vary. The product is said to improve brain and eye function. No serious adverse effects are known (2,3).

Drug interactions between natural remedies and traditional drugs are, in general, poorly studied. Therefore it is often hard to predict whether natural remedies can give rise to clinically important drug interactions. Some of the natural remedies that are available in Sweden are regulated by the medical product agency regarding the contents. However, there are several natural remedies, similar to Eye Q or containing evening primrose oil, on the market where the contents are not regulated.

No herb drug interactions between the contents of Eye Q or evening primrose oil and lansoprazole, cyproheptadine or cetirizine were found in the literature.

In one study, 47 male patients with mild essential hypertension were randomly allocated to three subgroups. The first subgroup received propranolol 80mg/day, the second supplement of fish oil (omega-3 fatty acids) 9g/day and the third both propranolol and fish oil. The patients in the first and second group were treated during 36 weeks and the third group were treated during 12 weeks. The result indicates that fish oil has a blood pressure lowering effect and that coadministration results in a synergistic lowering effect on the blood pressure (4).