The prescription should be as brief and simple as possible. It should be
explicit and clearly written. It may be expressed either in Latin or in
English. The manner in which the medicine is to be used should be
specified. Important instructions as to the rule, systematic regulations
or diet of the patient are sometimes necessary.
Prescriptions usually contain two or more of the following four
representative constituents: (1) The _basis_ or active ingredients. The
practice of conjoining several active medicines has wisely been
abandoned. Occasionally, however, it may be advantageous to give
together two medicines producing their effects in somewhat different
ways. Thus, spasms of the bowels are more often effectually controlled
by the conjunction of a stimulant like ether and an anodyne like opium
than by either given alone. Pain which is not alleviated by either
morphine or atropine is sometimes abated by giving them together. (2)
The _adjuvant_ is introduced in order to increase, moderate or modify
the action of the basis. Frequently its chief object is to insure
solubility and ready absorption. (3) A _corrective_ is occasionally
required to temper the effects of the basis. Thus a small dose of opium
is prescribed with oil or other laxative in cases of diarrhoea; ginger
is generally added to the aloetic mass to prevent its griping. (4) The
_vehicle_ generally consists of some comparatively inert substance,
added to facilitate administration, such as the treacle, linseed meal or
licorice powder used as an excipient for boluses and pills, the
benzoated lard or vaseline used for making ointments, and the water
given in drenches.
Example:
℞
Barb. Aloes ℥i.
Calomel ʒi.
Ginger ʒii.
Molasses ℥ss.
M. et fiat massa, in bolus 1.
Sig. Give at once.
--John Jones.
In the above prescription aloes is the basis; calomel as an adjuvant,
ginger as a corrective, molasses as an excipient.
* * * * *
A prescription is composed of several parts, which may be considered as
follows:
1. Heading.
2. Names and quantities of drugs.
3. Directions to compounder.
4. Directions to attendant.
5. Signature of writer.
1. For Gray Tom. July 22, 1916.
℞
{ Cupri sulph.,
2. { Ferri. sulph. exsic., aa. ℥iss.
{ Pulv. belladonna fol.,
{ Pulv. gentian rad. aa. ℥iii.
3. M. Ft. Chart No. XII.
4. Sig.--One powder three or four times daily in syrup.
--John Jones.