Dosage Determination for KPC
Herbal Granules
Concentrates are vacuum-dried granules of a decocted herb or formula and their dosage is less dependent on the density of the herb in its original form and more dependent on how easily the herb is extracted in the decoction process. Therefore, calculating the dosage of herb concentrates demands a unique method that is quite unlike that used for crude herbs. What is being weighed is a concentrate and not an agent that requires decocting. The system described here is what is used in Taiwan where concentrated granules have been prescribed for more than twenty years.
The usual adult dose is between 2 to 3 grams, three times a day; the most common is 3 grams per dose.
A four-step process can be used to arrive at appropriate dosages when using a combination of single herbs, combining two or more formulas, or using formulas in combination with single herbs:
- Calculate the total number of grams to be dispensed by multiplying the grams per day times the number of days the formula will be taken. For example, if ten days of herbs are to be given at 10 grams per day, to total equals 100 grams. (To simplify calculation, one can round the daily dosage to 10 grams per day—although 9 grams would be the actual amount taken.)
- Dose the single herbs in the prescription at 0.5 to 2 grams/day. Herbs which are typically given in small dose such as Yuan Zhi (Polygala) and Fu Zi (Aconite) should be about 0.5 grams/day and herbs which are typically prescribed in large doses such as Ji Xue Teng (Milettia) and Yi Yi Ren (Coix) should be prescribed at 1.5 to 2 grams/day. Most herbs should be dosed at 1 gram/day. Determine the total number of grams assigned to single herbs.
- Subtract the total number of grams assigned to single herbs from the total number of grams to be dispensed (from step 1). This number is the amount left for the formulas.
- Divide this amount among the number of formulas within the prescription allowing larger amounts for the formulas to be emphasized.
Here is an example of using a formula combined with single herbs. Let’s run through the four steps of dosage discrimination.
| Si Wu Tang (Tangkuei Four Combination) | 75 grams |
| Ye Jiao Teng (Polygonum Multiflorum) | 15 grams |
| Suan Zao Ren (Zizyphus) | 10 grams |
| Total | 100 grams |
- The prescription is for ten days and the dose is 10 grams/day. Thus the total number of grams we have to work with is 100.
- The next step is to determine the amounts of the single herbs in the prescription. In this prescription there are two single herbs. Since Ye Jiao Teng (Polygonum Multiflorum) is commonly given in large dosages we will give 1.5 grams/day (a total of 15 grams for ten days). Suan Zao Ren (Zizyphus) is assigned the normal daily dose of 1 gram/day (a total of 10 grams for ten days). The total number of grams assigned to all single herbs in the prescription is 25.
- Next, we subtract the number of grams assigned to single herbs (25) from the total number of grams we had to work with from step one (100). This leaves us 75 grams for the formula.
- Since this prescription only has one formula in it we give all 75 grams to that one formula [Si Wu Tang (Tangkuei Four Combination)]. If we had wished to include two formulas we would have divided the 75 grams between the formulas giving a larger dose to the more important formula.
Discussion
This four-step method works best when using one or two classical formulas with or without single herbs, but can be applied to all three strategies discussed above.
Dosages should be adjusted for children, older patients and patients with serious disorders. Small children can be given doses as small as 1 gram/day. Patients with serious, acute cases sometimes call for doses of 12-15 grams/day.
Herbs that are commonly given in small dosages owing to possible side effects should not be given in dosages that exceed 0.5 grams/day. It is best to start with an even smaller amount and gradually increase the dosage to make sure that the patient suffers no discomfort. Examples include: Xi Xin (Asarum), Fu Zi (Aconite), Yuan Zhi (Polygala), Wu Gong (Scolopendra), Quan Xie (Buthus), Cao Wu (Aconite Tsao Wu), Fan Xie Ye (Senna Leaf) and Lu Feng Fang (Wasp Nest).
Conclusion
Designing a prescription using concentrated granules differs greatly from what we are taught about prescribing crude herbs. The system above was designed to take the inherent qualities of this form of herbs into account and has been used effectively for over twenty years.
As the use of concentrates grows in the West it is certain that new insights will be gained on how to best administer them. In the meantime, it is hoped that this article will help practitioners take advantage of the convenience and effectiveness of this method of prescribing Chinese herbs.
Copyright ©1995 Andrew Ellis