For our purpose, pharmacokinetic properties entail changes in absorption, metabolism, and elimination of the drugs/herbs
whereas pharmacodynamic behaviors refer to how the herb/drug interacts inside the body (synergistic or antagonistic).
In general, herb/drug that alters the stomach pH (anti-acids), or intestinal motility (laxatives) will have an effect on absorption. Drug/herb metabolism occurs principally in the liver.
The duration (life-span) of an herb or drug in the body depends on whether the liver’s metabolism is induced or inhibited. An herb lasts longer in the body if its metabolism is inhibited by another drug; likewise, it is excreted faster if one’s liver metabolism is induced.
Further, drug/herb elimination primarily occurs at the kidneys and is affected by the individual’s kidneys function or by drugs’ toxic side effects. Lastly, the extent to which an herb-drug interacts depends on the individual’s health condition, age, body weight, metabolic rate, and dosage (11).
Ephedra and MAOI can cause dangerously high blood pressure. FDA proposed a dosage limit of 8 mg every 6 hours (or a total of 24 mg per day) and not more than 7 days of continuous use.
Ephedra, by itself, is not recommended for most people. It is never used alone in TCM
MAOI, caffeine, decongestants, stimulants
(Cao Mahuang, Ma huang, Yellow astringent)
• Dong Quai is safe for most adults. Women who are pregnant or breast-feeding should not take it without consulting their healthcare provider.
• Women with hormone sensitive cancers such as breast, uterine, or ovarian cancer and those with endometriosis or uterine fibroids should also exercise caution.
(Angelica Sinensis, Dong Gui, Chinese Angelica, Tan Kuei)
Primary use: It is most often used in oriental medicine for menstrual problems.
Dong Quai can also be widely found in traditional formulation for pain.
Decreases warfarin clearance and increases its bioavailability. Case report of hemorrhage.
Danshen (Salvia miltiorrhiza)
Primary usage: promotes blood flow and treat cardiovascular diseases i.e. angina pectoris, acute MI.
Primary actions: scavenges free radicals, inhibit platelets aggregration, and promote vasoactive.
Use of ephedrine and caffeine for weight loss
ephedrine (E) and caffeine (C) have been combined to make a pharmaceutical drug (EC) for treating obesity, and this EC combination was developed in Denmark according to strict pharmacologic research standards. Although some adverse events have been associated with the use of dietary supplements containing both E and C, most of them were related to misuse and abuse, according to the author.
Furthermore, ephedra (Ephedra sinica), which contains the alkaloids ephedrine,
pseudoephedrine, and norephedrine, has been used for thousands of years in traditional Chinese medicine as a potent but safe decongestant and bronchodilator. The importance of this herb is highlighted by the fact that pseudoephedrine is an ingredient in most over-the counter (OTC) medications for cold, flu, and sinus symptoms. Despite this history, several states banned the selling of ephedrine and ephedra in dietary supplements, and the Food and Drug Administration (FDA) also banned ephedrine in all dietary supplements in April 2004. In this op-ed article, the author considers whether this ban on ephedrine in weight-loss
products is appropriate and supported by sufficient scientific evidence.
Over 30 clinical studies of the use of EC combinations (both pharmaceutical and herbal
preparations) in humans have been conducted, and they show that when EC is used as
directed, it is safe and effective. For example, in a randomized, double-blind, placebo controlled trial, the use of herbal ephedra–caffeine for six months led to weight reduction and improvement in blood lipid concentrations without significant adverse effects.1 Similarly, the use of EC in combination with aspirin was found to safely and effectively promote weight loss both in nonexercising patients and in patients whose energy intake was not restricted.2,3 In another randomized, double-blind, placebo-controlled study, the effects of diet plus either EC, ephedrine alone, or caffeine alone were studied; EC was found to be an effective treatment whereas ephedrine and caffeine by themselves were ineffective.4
Although all of these studies were performed in adults, another randomized, double-blind,
Placebo-controlled trial in adolescents showed that EC is a safe and effective treatment for obesity in this population also. None of the reviewed studies found any serious side effects related to the use of EC as an ant obesity drug. Finally, all of the studies concluded that EC is a safe and effective weight-loss treatment in overweight and obese persons who are otherwise healthy.
In summary, the results of numerous double-blind, placebo-controlled studies indicate that
for overweight and obese adults and adolescents, the use of EC as directed is a safe weight loss treatment that is not associated with significant side effects.
Although ephedrine abuse can lead to serious and even deadly side effects, the statistics associated with such abuse pale in comparison with those associated with the abuse of ibuprofen, paracetamol (acetaminophen), and aspirin. Yet these OTC products remain in the marketplace whereas ephedrine is banned. This ban was enacted even though a panel of experts convened by the FDA concluded in 1997 that the use of improved warning labels on ephedrine-containing products rather than a ban was the most appropriate course of action. The author also cites a review6 that showed that the FDA misinterpreted the adverse-reaction data for ephedrine.
Licorice (Glycyrrhiza glabra) contains glycyrrhizin,
which inhibits 11b-dehydrogenase, 5a-reductase, and
5b-reductase. Glycyrrhizin is metabolized largely to
glycyrrhetinic acid (an even more potent inhibitor of
5a-, 5b-reductase and 11b-dehydrogenase). Liquorice
has been shown to increase plasma concentrations of
prednisolone [22, 23]. It also potentiated the cutaneous
vasoconstrictor response of hydrocortisone . Licorice
is a common herb in Chinese and Japanese herbal
mixtures. The effect of several such mixtures on
prednisolone concentrations has been tested. Both Shosaiko-
To and Xiao Chai Hu Tang decreased the plasma
AUC of prednisolone  whereas Saiboku-To increased
it. Sairei-To did not affect it . Both Sho-saiko-To
and Rikkunshi-to were found not to affect the pharmacokinetics
of a single oral dose of o¯oxacin 
St John's wort affects the clearance of many drugs,
including cyclosporin, antidepressants (predominantly
SSRIs), digoxin, indinavir, and phenprocoumon. The
underlying mechanism appears to be multifactorial. There
is evidence of a strong interaction with P-glycoprotein
(PgP), an ATP-dependent drug ef¯ux transporter known
to pump drugs out of the cell membrane, thus decreasing
intracellular concentrations . St John's wort increases
expression of duodenal PgP/MDR1 . The herb also
induces the activity of an important form of cytochrome
P450, CYP3A4. However, results of studies of the
effect of St John's wort on CYP3A4 are con¯icting.
While three enzyme marker studies indicated a potent
inducing effect of St John's wort (300 mg three times
dailyr14 days) on CYP3A4 activity [29, 30], two others
found no effect (both 300 mg three times daily, one for
3 days , the other for 8 days ) on CYP2D6 or 3A4
activities. It is possible that the negative trials were simply
too short in duration. Alternatively, differences in quality
of the HMPs used might explain the discrepancy. One
study examining the effect of St John's wort on CYP1A2
activity (using a caffeine/dextromethorphan probe) found
that it (300 mg three times daily for 8 days) had no effect
on 17 DMX/caffeine ratios , indicating that this
HMP has a low potential for drug interactions involving
Cases of serotonin syndrome could arise if St John's
wort increased serotonin levels. However, it cannot be
considered an SSRI, because in vitro, St John's wort
inhibits the uptake of serotonin, noradrenaline and
dopamine only at high concentrations with IC50s of
2.4, 4.5, and 0.9 mg mlx1, respectively  which are
unlikely to be achieved with oral dosing. However,
enough cases of interactions with SSRIs have been
reported that a serotonergic (or serotonin-amplifying)
effect of St John's wort could occur.
There is reasonable documentation of interactions
between coumarin anticoagulants and St John's wort,
danshen, dong quai, ginseng, and ginkgo . Most of
these case reports are probably not true interactions but
result from additive anticoagulant effects. Dong quai
contains coumarins, and would be expected to augment
the effects of a coumarin-derived anticoagulant. Ginkgo
and garlic interfere with platelet function, and have been
associated with bleeding even in the absence of warfarin
or other anticoagulant treatment. Danshen also interferes
with platelet function but appears to decrease the elimination
of warfarin at least in rats . In a recent case
report, the INR of a patient taking warfarin who drank
0.5±1 gallon of green tea (Camellia sinensis) was seen to
Inadequate reporting makes it dif®cult to determine
whether a herb±drug interaction has occurred. Authors
should be required to document all relevant information
(see above). The adverse event should be clearly
described, alternative explanations should be explored and
a rechallenge should be considered. The HMP should
be analysed to ascertain the contents of the product. Even
well-documented case reports can only serve as a critical
early warning system.
Herb±drug interactions occur but are under-researched.
In many cases there is no plausible mechanism to explain
the observed phenomena and causality is uncertain.
Patients taking St John's wort or anticoagulants are at
the highest risk of an interaction. Patients on coumarin
anticoagulants should be speci®cally advised to avoid
taking herbal medicines or to have their INR measured
within 2 weeks of starting the product. Patients
taking garlic, ginkgo, danshen, or other HMPs affecting
platelet function should also be monitored. The
risks of combining St John's wort with drugs or
anticoagulant drugs with herbal medicines should be