Robert Tisserands new edition of Essential Oil Safety is due out 30th September 2013
Safety Tips shared by Andrea Butje at Aromahead Institute on NAHA's Member Only Forum:
My guideline is to use essential oils only externally and at low (1%) dilutions with people who are taking many medications, who have impaired liver function (detoxification and metabolism of drugs and essential oils depends on the liver), impaired kidney function (as the kidney excretes packaged toxins from the liver), are suffering from chronic diseases, and those who are elderly or very young.
1. Use caution with Peppermint oil and calcium channel antagonists. Peppermint oil is a calcium channel blocker and may alter the effect of these drugs. Calcium channel blockers are a common medication given for high blood pressure. In this instance, Peppermint may potentiate the medication.
2. 1,8 cineole containing oils ( a few examples are Ravintsara, all Eucalyptuses, Rosemary camphor/ 1,8 cineole, Cardamom, many species of Helichrysum, Laurel Leaf, Myrtle, Spike Lavender) should not be used with barbiturates. 1,8 cineole increases the metabolic detoxification of these drugs, thus decreasing their effectiveness (reducing the dose more quickly than expected).
3. Methyl Salicylate (Birch, Wintergreen), Peppermint and Eugenol (Clove, Basil ct eugenol) containing oils should be avoided with anticoagulant drugs such as Warfarin (coumadin). These essential oils, and the component eugenol, are known anticoagulants and may potentiate the effects of the drugs, as the essential oil component is offering the same action as the drug.
People who have aspirin sensitivity should not use Methyl Salicylate containing oils (Birch, Wintergreen). Methyl Salicylate is converted into salicylic acid in the body. Here is an example of a component of an essential oil being the same as the concentrated ingredient of the drug. Check your GC/MS Reports.
4. All oils containing Eugenol (Clove) and Methyl Salicylate (Birch, Wintergreen) should be avoided by people with clotting disorders. This is because these components “thin” the blood and could cause excessive bleeding.
5. If drugs are being given transdermally (skin patch) essential oils must not be applied to the area of the drug patch, or the close vicinity. This is to avoid possible alterations in the drug’s bioavailability. The essential oils could speed up or slow down the delivery of the drug, thus altering the assumed dose.
6. If there is significant hepatic (liver) and renal (kidney) impairment the person will be more vulnerable to the potential toxic effects of the oils with overuse. Intensive or internal use of the oils must be avoided.
7. Eugenol, Thymol and Carvacrol (Clove, Thyme ct. thymol, West Indian Bay Oil) are potent prostaglandin inhibitors and are to be avoided by people with significant renal (kidney) disease. This is because drug treatment for renal disease increases renal blood flow by mechanisms that are dependent on the effects of prostaglandins.
Inhalation provides a very quick absorption into the blood stream while applying the oil to the skin allows for slow, continuous absorption over a period of time, especially if applied during a massage. My understanding is that most safety concerns with essential oils and drug interactions are with oral, rectal and vaginal use of the oils (or the intensive use of neat oils on the skin). Of course, the transdermal issue has to do with using the oil on the skin.