Ayurvedic Herb-Drug Interactions, Stated Plainly
A handful of the most used Ayurvedic plants have known interactions with prescribed drugs, and the tradition states them plainly as part of its knowledge of each plant. Ashwagandha interacts with thyroid medication and sedatives. Brahmi interacts with anticholinergic drugs. Guggulu interacts with anticoagulants and thyroid drugs. Yashtimadhu, licorice, interacts with blood-pressure drugs and lowers potassium. Haridra, turmeric, in high dose interacts with anticoagulants. Pippali and the Trikatu formulas raise the absorption of whatever is taken with them. Each follows from the plant's rasa, virya, vipaka, and prabhava, its taste, potency, post-digestive effect, and specific action, and the reasoning is given below with the classical dose.
The table
| Plant | Properties | Interacts with | Classical dose |
|---|---|---|---|
| Ashwagandha, Withania somnifera | bitter, astringent, sweet; heating; sweet vipaka; rasayana | thyroid medication; sedatives | churna 3 to 6 g with milk |
| Brahmi, Bacopa monnieri | bitter, astringent; cooling; sweet vipaka; medhya | anticholinergic drugs | churna 1 to 3 g with ghee or honey |
| Guggulu, Commiphora wightii | bitter, pungent, astringent; heating; pungent vipaka; lekhana | anticoagulants; thyroid drugs | purified gum 1 to 3 g in a formula |
| Yashtimadhu, Glycyrrhiza glabra | sweet; cooling; sweet vipaka; rasayana | blood-pressure drugs; potassium; diuretics | churna 2 to 4 g with milk or honey |
| Haridra, Curcuma longa | bitter, pungent; heating; pungent vipaka; lekhana | anticoagulants, in high dose | churna 1 to 3 g with warm milk |
| Pippali, Piper longum | pungent; mildly heating; sweet vipaka; yogavahi | raises absorption of drugs taken with it | churna 0.5 to 1 g with honey |
Ashwagandha
The root is ushna, heating, and balya, strength-giving; it kindles agni, the digestive fire, and the fires of the tissues. Taken with levothyroxine it adds to the drug and the person can drift into the signs of excess: heat, a racing heart, sleeplessness, weight loss. Taken with a benzodiazepine or a sleeping drug it deepens sedation, since its rasayana action on the mind is calming and heavy.
Brahmi
Brahmi is medhya by prabhava, an intellect-promoting plant that sharpens memory and steadies the mind, and it works through the same faculties that anticholinergic drugs, given for bladder, bowel, tremor, and allergy, blunt. The two oppose one another, and the drug loses effect or the plant does. Brahmi is cooling and suits Pitta and Vata. In some regions the name is also given to Mandukaparni, Centella asiatica; the interaction is stated for Bacopa.
Guggulu
Guggulu, the purified resin, is lekhana, scraping, by prabhava: it thins Kapha, clears the channels, and reduces fat and swelling, which is the reason it is in Yogaraja Guggulu, Kaishora Guggulu, and Triphala Guggulu. The same scraping action thins the blood, and with warfarin or another anticoagulant bleeding becomes more likely. Guggulu also stimulates the thyroid, as its heat and its lightness predict, and it adds to thyroid drugs as Ashwagandha does. Guggulu is never used raw; shodhana, purification by boiling in Triphala decoction, precedes every formula. Commiphora wightii, also written Commiphora mukul, is endangered in India, and regulated cultivation is the modern answer.
Yashtimadhu
Licorice root is sweet, heavy, cooling, and building, a rasayana for the voice, the eyes, and the gut lining. Its fault is water. Taken daily beyond a few weeks it holds sodium and water and lets potassium go, and the blood pressure rises; with a blood-pressure drug it works against the drug, with a diuretic it deepens the potassium loss, and with digoxin the low potassium is dangerous. The tradition's own caution is the same in its terms: a sweet, heavy, Kapha-increasing substance is not for long use in a person with swelling or heaviness, and it is given in short courses.
Haridra
Turmeric in cooking quantity has no interaction. In the classical medicinal dose of 1 to 3 grams, and more so in the concentrated extracts sold today, its lekhana and blood-moving action adds to anticoagulants and to the days around surgery. It is heating and drying and is given with warm milk to a Vata person and with honey to a Kapha person.
Pippali and Trikatu
Long pepper is yogavahi by prabhava: it carries whatever it is given with deeper into the tissues, which is why it is the vehicle in so many formulas. The modern finding that its constituent raises the blood levels of many drugs is the same fact from the other side. A person on a drug with a narrow margin, an anti-epileptic, a heart drug, an immunosuppressant, who takes Trikatu with it raises the drug's effect.
The metal preparations
Rasa Shastra, the branch of pharmacy that prepares bhasmas, calcined ashes of mercury, iron, gold, lead, copper, and arsenic minerals, belongs to the classical tradition and is used in the Indian clinics today. The modern layer is that improperly prepared bhasmas have caused heavy-metal poisoning, and that regulated manufacture and testing under the Indian pharmacopoeia exist for that reason; a bhasma is taken only from a licensed maker with the batch tested, and never with another source of the same metal. Herbalism shares most of these plants and states the same interactions under their English names.
Not medical advice.