Complementary and alternative medicines:

Complementary and alternative medicines:  safety issuesSafety of complementary and alternative medicines

The potential for harm is not insignificant with a number of CAM treatments. Of concern is that up to 70% of patients will not tell their doctors that they are using these products. Some do not consider herbal products as medications, and others believe their doctor will not be interested or may even be judgmental.

Many complementary and alternative medicines are exempt from the requirement of scheduled medicines to demonstrate efficacy. They can be registered for use by demonstrating safety in the form presented. Claims made by the product must be restricted and of limited scope; conditions being treated are generally considered to be mild and/or self-limiting. Efficacy may or may not be established through clinical studies. Effective doses of active ingredients can vary widely between products due to the range of plant parts used, and different methods of processing.

Significant drug interactions have been identified between some herbal products and conventional medicines.

Herbal products can interact with conventional medications, leading to increases in potency or decreased efficacy Some agents (Ginkgo biloba, devil’s claw, ginger, garlic) may have antiplatelet/anticoagulant effects and may exacerbate gastrointestinal bleeding if used with nonsteroidal anti-inflammatory drugs (NSAIDs). Interactions with warfarin could lead to potentially fatal results. Echinacea may be hepatotoxic and should be used with care in patients taking disease-modifying antirheumatic drugs (DMARDs), many of which also have liver toxicities.

For full information physicians need to access appropriate websites or contact a pharmacist.

Some adverse effects associated with selected complementary and alternative medicines (CAMs) (Table 12.6)

CAM	Contraindications / precautions	Adverse drug reactions	Herb–drug interactions
celery	possible abortifacient (avoid in pregnancy)	CNS depression allergic dermatitis hypersensitivity phototoxicity	diuretics—possible additive effect
devil’s claw	diabetes (hyperglycaemic action) peptic ulcer disease warfarin therapy	minor gastrointestinal	warfarin—case report of increased bleeding with combined use
evening primrose oil	schizophrenia epilepsy (increased risk) pregnancy (safety unknown)	mild gastrointestinal	antipsychotics—increased risk of seizures in patients on phenothiazines
feverfew	hypersensitivity to daisy family pregnancy (abortifacient, uterine stimulant)	mouth ulcers dry sore tongue swollen lips/mouth loss of taste gastric disturbance	warfarin—possible increased anticoagulant effect
ginger	avoid excessive doses in patients on cardiac, antidiabetic, or anticoagulant therapy pregnancy (abortifacient and uterine stimulant in animals)	hypersensitivity dermatitis dyspepsia	warfarin—increased bleeding risk antacids—reduced activity of antacids due to increased gastric secretions