Sun28November0333PM 13

Herbal remedies are widely used and their side effects and herb-drug interactions can be significant.

Which one of these herb side-effect or herb-drug interaction pairing is correct?

(Please select 1 option)

Kava : immunostimulation

Garlic : sympathomimetic effects

Ephedra : increased bleeding time

St. John's Wort : serotonin syndrome Correct

Ginkgo Biloba : potentiation of GABAA agonists

Explanation

Patients presenting for surgery may be taking prescription drugs and herbal remedies. Both have implications for anaesthesia as they are a source of drug interactions.

Ephedra (Ma Huang) is a medication extracted from the plant Ephedra sinica and is used principally as a CNS stimulant, weight loss and the treatment of asthma. It is a mixture of alkaloids including ephedrine. It is a directly acting alpha and beta adrenoreceptor agonist and promotes noradrenaline release from pre-synaptic neurones. The co-administration of sympathomimetic agents can lead to cardiovascular instability.

Ginkgo Biloba has anti-oxidant properties and is used for the treatment of early-stage Alzheimer's disease, vascular dementia and peripheral vascular disease. By inhibiting platelet activating factor (PAF) it reduces platelet adhesiveness and increases the potential for bleeding, especially in those patients already on anticoagulants and antiplatelet drugs.

The extract from St. John's Wort is used an antidepressant it not only a serotonin uptake inhibitor but is a cytochrome P450 isoenzyme inducer. There is potential for the development of serotonin syndrome when drugs such as fentanyl or tramadol are given during the course of an anaesthetic.

Kava is derived from the root of a pepper (Piper methysticum)

It is a weak GABAA agonist producing anxiolysis and sedation. It has the potential to enhance the effects of the volatile anaesthetic agents, propofol and the benzodiazepines.

Garlic is derived from allium sativum and used for the treatment of hypertension and hyperlipidaemia. It contains cysteine that irreversibly inhibits platelet aggregation, potentiating the effects of aspirin and the NSAIDs.

The popular herbal remedy Echinacea is known to stimulate the immune system by modulation of cytokine signalling. It should be avoided in patients requiring organ transplantation.

Reference:

Herbal Medicines and Anaesthesia

Answer Statistics

1

3%

2

3%

3

6%

4

76%

5

14%

Times answered: 313