2. Herbal remedies means treatment of diseases with herbs.
Herbalism ("herbology" or "herbal medicine") is use of plants for
medicinal purposes, and the study of such use.
Plants have been the basis for medical treatments through much of
human history, and such traditional medicine is still widely practiced
today.
The World Health Organization estimates that 80 % of the
population of some Asian and African countries presently use herbal
medicine for some aspect of primary health care.
The use of herbal remedies is more prevalent in patients with
chronic diseases such as cancer, diabetes, asthma and end
stage renal disease.
3. In India the herbal remedy is so popular that the government of India has
created a separate department—AYUSH—under the Ministry of Health &
Family Welfare. The National Medicinal Plants Board was also established
in 2000 by the Indian government in order to deal with the herbal
medical system.
TOXICITY IN HERBALS AND THEIR INTERACTIONS:
Some plant descriptions in traditional herbal medicine (e.g. traditional
Chinese medicine) have changed over time, which may lead to
unintended intoxication by using wrong plants.
A problem is also the contamination of herbals with microorganisms,
fungal toxins such as aflatoxin, with pesticides and heavy metals
4. Unprofessional processing, which differs from safe traditional
preparation represents another potential source for herbal
poisoning.
Unwanted effects of herbal products may also develop by the
interaction of herbs with conventional drugs upon
concomitant intake.
The art of herbal medicine is to dissect pharmacologically
and therapeutically valuable herbal drugs from harmful and
toxic ones and to develop combinations of medicinal plants as
safe and efficient herbal remedies.
Standardization and strict control measures are necessary to
monitor sustainable high quality of herbal products and to
exclude contaminations that badly affect patients consuming
herbal medicine.
5. Examples of highly toxic herbs include:
• Poison hemlock and nightshade. They are not marketed to the public
as herbs, because the risks are well known, partly due to a long and
colorful history in Europe, associated with "sorcery", "magic" and
intrigue.
• A case of major potassium depletion has been attributed to chronic
licorice ingestion., and consequently professional herbalists avoid the
use of licorice
• Black cohosh has been implicated in a case of liver failure.
• Examples of herbs where a high degree of confidence of a risk long
term adverse effects can be asserted include ginseng, which is
unpopular among herbalists for this reason, the endangered herb
goldenseal, milk thistle, senna, against which herbalists generally
advise and rarely use, aloe vera juice, buckthorn bark and berry,
cascara sagrada bark, saw palmetto, valerian, kava, which is banned
in the European Union.
6. The safety of herbal medicines
has become an issue for the
regulatory authorities, as
serious effects have been
reported, including
hepatotoxicity, renal failure and
allergic reactions
Systematic pharmacovigilance
is essential to build up reliable
information on the safety of
herbal medicines for the
development of appropriate
guidelines for safe
effective use.
Herbal medicines are traditionally
considered harmless since these
belong to natural sources.
However, this is not true as there
are several case reports of adverse
reactions of herbal drugs
mentioned in published literature
The World Health Organisation,
recognising the growing
importance of the use of herbal
medicines worldwide developed
guidelines for the monitoring of
herbal safety within the existing
pharmacovigilance framework.
7. Herbs with Adverse Drug Interactions
Herb Drug Adverse Effects
Ginkgo biloba Drugs like Aspirin,
warfarin, ticlopidine,
clopidogrel,
dipyridamole, garlic,
vitamin E
With aspirin -retards
aspirin absorption
Psyllium seed Coumarin derivates Retards absorption of
drug
Ephedra Caffeine,
decongestants,
stimulants
May be additive in
nature
8. ADVANTAGES OF HERBAL MEDICINE:
More closely related to our body structure
because we are composed of nature
Do not alter hormone balance, change
chemical levels in the brain or trick your body
Disadvantages of Herbal Medicine:
Would not be able to treat serious trauma,
such as a broken leg
Would not able to heal appendicitis or a
heart attack as effectively as conventional
drugs would using modern diagnostic tests,
surgery, and drugs.
HERBAL MEDICINES Vs
CONVENTIONAL MEDICINE
9. Advantages of Conventional
Medicine
Provides full attention to the patient as
the doctor or therapist is able to fully
dedicate himself or herself to the
patient and it helps in the healing
process
There exist many conditions that
indispensably require conventional
treatment
Disadvantages of Convectional
Medicine:
Many side effects that seem to sometimes
harm patients more than it helps them
May be hard to afford; rising cost
These drugs are made in labs, rather
than by nature, they are given a stamp of
approval even when their side effects
may harm people
14. Pharmacokinetic Interactions
Absorption
Interactions affecting absorption result in a reduction/increase of
the absorption of the drug.
Changes in intestinal pH, complexing mechanisms and drugs
affecting intestinal motility will affect absorption.
For example, herbs such as aloe leaf, guar gum and senna, which
are common ingredients in herbal weight-loss products, exert a
laxative effect that may decrease intestinal transit time and reduce
drug absorption.
15. St. John’s Wort induces intestinal P-glycoprotein, which may
decrease the absorption of common P-glycoprotein
substrates, such as digoxin.
Such effects may be reduced if the drug is consumed 1 hour
before or 2 hours after the herb.
Distribution:
A drug with high plasma protein binding (e.g. warfarin,
carbamazepine) that has a small volume of distribution may
be displaced by a herb competing for the same binding sites.
16. Drug displacement from protein-bound forms, by concurrent
drug administration, causes an increase in serum drug levels
and which may lead to an increase in therapeutic effect.
Metabolism
Enzyme Induction
A decrease in the amount of drug could occur by stimulating
the production and activity of enzymes that degrade the drug
and prepare it for elimination from the body.
Such is the case with St.John’s Wort which induces the
cytochrome P450 enzymes which are responsible for the
metabolism of several drugs.
17. This is a common mechanism and applies to the way in
which St. John’s Wort may reduce the efficacy of the oral
contraceptive pill or blood levels of warfarin, digoxin,
protease inhibitors, theophylline, carbamazepine.
Enzyme Inhibition:
The opposite may also occur, in which the herb inhibits the
production of the enzyme required to break down the drug,
hence increasing the drug levels.
Unlike enzyme induction, which may take several days or
weeks to develop fully, enzyme inhibition can occur within
2-3 days resulting in a rapid development of toxicity.
18. Licorice decreases the metabolism of corticosteroids, leading
to adverse and toxic effects from the build-up of
corticosteroids.
Evidence obtained in vitro suggests that echinacea and
chamomile may inhibit the cytochrome P450, isoenzyme
CYP3A4.
Concurrent use with drugs like alprazolam, simvastatin,
calcium-channel blockers, and protease inhibitors could
potentially increase serum drug levels and adverse effects.
19. Excretion
Changes in excretion may also affect serum drug levels.
Herbal diuretics are quite weak and unlikely to cause large
problems.
However, chronic ingestion of licorice may result in
hypokalemia and water retention and accordingly may
interfere with various medications including
antihypertensive and antiarrhythmic agents.
20. Pharmacodynamic Interactions
Additive interactions
A herb might produce the same kind of effect as the drug and give
an increase in the drug effect (without increasing the amount of
the drug).
Therefore herbal sedatives, anticoagulants, antihypertensives and
others may possibly increase the effect of a concurrent
conventional drug taken for the same purpose.
For example, the hyponotic activity of benzodiazepines is increased
by valerian, and the anticoagulant action of warfarin is enhanced
by gingko, garlic and ginger
21. Antagonistic interactions:
A herb might produce an effect that is contrary to the effect
desired for the drug, thereby reducing the drug effect.
Ephedra or caffeine-containing herbs (cola nut, guarana,
mate, green tea), often used in combination for the additive
cardiovascular effects in many herbal weight-loss products,
may antagonize the effects of antihypertensive medications.
22. Quality control of herbal drugs (WHO guideline)
1. Authentication (stage of collection, parts of the plant
collected, regional status, botanical identity like phyto-
morphology, Microscopical and histological analysis,
taxonomical identity, etc.)
2. Foreign matter (herbs collected should be free from soil,
insect parts or animal excreta, etc.)
3. Organoleptic evaluation (sensory characters – taste,
appearance, odour, feel of the drug, etc.)
4. Tissues of diagnostic importance present in the drug
powder.
23. Quality control of herbal drugs (WHO guideline)
5. Volatile matter
6. Moisture content determination
7. Chromatographic and spectroscopic evaluation.
8. Determination of heavy metals – e.g. cadmium, lead,
arsenic, etc.
9. Pesticide residue
10. Microbial contamination
11. Radioactive contamination
