NATURAL PRODUCTS
Hawthorn (Crataegus species)
Hawthorn (various species of crataegus) has found a
niche as a natural product for the treatment of mild to moderate heart failure (NYHA II;
New York Heart Association II) in Germany. It causes an increase in coronary blood
flow and prolongs the refractory period (the time in which the heart muscle does not
contract after a contraction) of the heart. And it has been shown to have both
positive chronotropic (increased heart rate) and positive inotropic (increased force of
contraction) effects on the heart, which results in an increase in cardiac output and an
increase in myocardial oxygen consumption. Consequently, it should not be used by
people with cardiac disease with or without angina unless under the direct supervision of
a physician or cardiologist.
A study using rat hearts showed that pretreatment
with crataegus extract preserved myocardial cell membranes and protected the cell from
damage during ischemia and reperfusion. Substantial clinical study would be needed
to show whether crataegus extract could be of benefit as a pretreatment for open heart
surgery in humans as an adjunct to cardioplegic solutions. Crataegus oxycantha has
been studied and has found use in the treatment of angina, congestive heart failure,
cardiac arrhythmias, and angina.
Until recently, it was thought that the actions of
Hawthorn were due to its inhibition of phosphodiesterase and its effect on calcium
channels in cardiac muscle. Using guinea pig heart muscle, Muller, Linke, and Klaus
in 1999 found that crataegus had no effect on the calcium channels, but it did have an
inhibitory effect on potassium current within the myocardium, similar to class III
antiarrhythmic drugs. They concluded that the positive inotropic effect of crataegus
(hawthorn) was caused by the inhibition and delay of potassium repolarization within the
myocardium and that calcium channels and phosphodiesterase inhibition did not play a part
in increasing the force of ventricular contractions. Based on this new information,
there may not be a potential drug interaction with theophylline or caffeine, which are
both phosphodiesterase inhibitors. However, caution should still be exercised with
the use of hawthorn with them and with caffeinated beverages like coffee, tea, and colas.
Hawthorn has been used to help improve cardiac
performance in people with mild coronary insufficiency, but it should not be a substitute
for proven prescription drug therapy. A physician should be consulted before using
Hawthorn. Like other natural products, there is no set dosage, quality and standards
are an issue, and further studies are needed to determine safety, duration of therapy, and
efficacy. The suggested dosages reported in the literature range from 160 - 900 mg
of the extract daily. Thus, dosages must be individualized based on patient
response, which can only be determined by a physician.
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product pages is only a guideline based on current literature and the pharmacological
action of these products. It should not be used as the sole source of information on
these products. Many of the drug interactions listed are not found in current
literature but are based on likely interactions due to the actions of the interacting
drugs. It is recommended that a qualified and licensed healthcare professional be
consulted for additional information. Although the information provided is from
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This page was last updated on 04/29/05. |
