Herbal medicine
Background
Natural or botanical health products
Overview of usage of herbal products for health
Different Types of Herbal Products
Supervised by health care practitioners
As self-care products, self-directed use (NPHs regulations)
Issues with Botanical Health Products
Concern about predictable quality and health benefit?
Biological effects are induces by secondary plant metabolites, which are produced by plants for self-defense, survival…
Levels are influenced by various stresses:
Environmental conditions
Soil conditions
Seasonal effects
Harvesting and Productions methods
Microbial & chemical Contaminants.
Efficacy (health claims) and safety depend on sourcing, harvest practices, processing, manufacturing, and storage.
Canadian regulations introduced. Natural and Non-prescription Health Products Directorate (NNHPD) of Health Canada
What are NHPs?
Traditional medicine plus:
A plant or plant materials, fungus or non-human animal materials
An extract of a)
A vitamin
An Amino Acid
An Essential Fatty Acid
A Mineral
A Probiotic (Eg. Acidophilus)
For OTC use only. All products have to be licended.
New regulatory framework is being proposed
What can we expect of these licensed products?
Licencing requirements:
Data for Pre-marketing assessment:
Quantity of medicinal ingredients and specification compliance with GMP… product quality
Health claims
Safety and Efficacy data
Post market monitoring of adverse events and report to Health Canada
Level of evidence required is different depending on: Traditional use Vs Non-traditional use
Three Levels of Health Claims for Non-traditional use:
Risk reduction: Reduce the risk of developing a specific disease or condition by altering a recognized risk factor. (oxidant stress and antioxidants).
Structure-function claims: the effect on a structure or physiological functions of human body E.g. “Maintains healthy gums” or “reduces blood cholesterol levels” or “improve liver function”.
Treatment/therapeutic claims: diagnosis, treatment and mitigation or prevention of a disease, disorder, or abnormal physical state or its symptoms in humans.
Safety Issues of NHPs “Rate of Adverse Health Effects – Low” Much lower than drugs
Underestimated?
Consumers: Consider these products as natural and therefore safe
Some physicians consider NHPs are placebos… thus reduces the like hood of associating any adverse reaction with any NHP usage.
Patients are embarrassed to admit the actual amount used when there is an adverse reaction
Report of adverse reactions to NHPs by health-care professionals can adverse Drug Reaction Monitoring Program
Case report: difficult to establish causal relationship
FACTORS AFFECTING EFFICACY AND SAFETY OF NATURAL HEALTH PRODUCTS
Product Factors affecting efficacy and safety
Lack of quality control
Contaminations: bacteria and fungi, pesticides, heavy metals, radioactive residues
Wrong substitution: wrong her being incriminated
Adulterants:
Eg. Asian Patent medicines
*Usually contain multiple components
*Contains prescriptions drugs, heavy metals, and other ingredients that may or may not be listed on the label.
Consumer Factor affecting efficacy and safety: Inappropriate use by consumers
Misconceptions and over-dosing
“All natural health products are ‘safe’ “ and “More is better”.
Consume excessive doses.
E.g. Miss-use of weight loss and energy/tonic products
May contain diuretics, laxatives and caffeine, ephedrine and amphetamines.
Chronic use >> overdose and toxicity.
E.g. Cu 30mg/day for 3 years and 60 mg/day for 1 year >> Liver cirrhosis, hepatic failure.
Max dose is 3 mg/day!
“Multiple products exposure”
E.g. Zn overdose and Leukocyte aplasia from:
5 different products: Vitamins, minerals, fish oils/linoleic acid, amino acids, and enzymes >> A total Zn of 36 mg/day – over twice recommended dose.
Herb-Drug Interactions
Most people who use NHPs also take drugs at the same time; and do not tell their physician about it.
Who may be at risk to H-D interaction?
Chronic conditions or life-threatening prognoses: cancer, HIV, Alzheimer’s disease, irritable bowel syndrome, chronic fatigue syndrome
Frustrated with conventional medications: patients from rheumatology, hemodialysis, organ transplant.
Examples of Clinically Significant Interactions, according to mechanisms:
Pharmacokinetic interactions: herb alters the pharmacological effects/toxicity by modifying the plasma concentration of the drug via changes in:
Absortion
Distribution
Ecretion
Metabolism
Pharmcodynamic interactions: herb alters the response of the drug target without changing the drug plasma concentration.
