This section is from the book "A Text-Book Of Materia Medica And Pharmacy For Medical Students", by Velyien Ewart Henderson. Also available from Amazon: A Text-Book of Materia Medica and Pharmacy for Medical Students.
When the physician has decided upon the drugs which he wishes to administer to a patient, the form, pill, powder mixture, etc., in which he wishes to administer them, and the preparations that are best suited to the form chosen, he has still to write a prescription which will convey his wishes clearly and concisely to the pharmacist. Even if the physician does his own dispensing the writing of a careful prescription is not to be omitted, as it is essential that he have for the purpose of consultation in the future a statement in writing of the treatment adopted, also the writing of a prescription will save many errors in dispensing. The question of the ownership of the prescription is a doubtful one some claiming that it is simply an order by the physician to the pharmacist, who should keep it as a record of the orders given him. On the other hand very many persons hold that the prescription is the property of the patient to whom it is given. The pharmacist can hardly refuse to give the original holder of the prescription a copy thereof, unless he has distinct orders not to do so from the physician. In view of this when the physician writes a prescription which he does not want repeated he should not only mark it " ne repetatur" but should also inform the patient that this prescription is one in which he has no proprietory interest but is only the physician's instructions to the pharmacist. This precaution should always be taken when prescribing morphine in any form. The pharmacist is expected, not only to refuse a copy of any prescription to any person other than the one to whom the physician gave it, but also not to make any further use of it.
The prescription was formerly written entirely in Latin, and even today the great majority of prescriptions are written largely in that language. This custom possesses some distinct advantages. The official Latin names are concise and distinctive so that there is little danger of error. Formerly when Latin was the universal language of science and medicine, it ensured that the prescription could be universally read and understood, this still to a certain extent holds good as most civilised governments have adopted official Latin names in their pharmacopaeias, though unfortunately the Latin names adopted differ slightly in different countries.
It is a good rule to write the names of the drugs and the directions to the pharmacist if they be simple and well understood in Latin while the directions to the patient which are to be inscribed by the pharmacist upon the label should be written in English as this ensures that no error will arise in translation. The directions to the dispenser may of course be given in English and indeed it is well to do so if they are at all unusual. Directions to the patient should as a rule be written in English, but there are a few simple directions which have been so much used that the abbreviations of their Latin translation are very commonly employed. The student will often find in older books prescriptions with Latin directions. For these reasons he should make himself familiar with the phrases given in the vocabulary.
In writing a prescription always write legibly. Do not endanger the success of your treatment or possibly even the patient's life by careless, illegible hand-writing. Whenever large quantities of any powerful drug are ordered, and especially if they surpass the pharmacopaeial dose, the quantities should be not written in numerals but should also be written out in full in words.
The following is a typical prescription:-
The words to the left, inscription, superscription, subscription and signature, are the names applied to those parts of the prescription opposite which they are set. The signature includes the directions to the patient. The other three parts are for the pharmacist. The subscription includes the compounding directions to the pharmacist.
The following is a transcription in unabbreviated Latin of the above prescription with an interlinear translation.
For Arthur H. Recipe
Potassii Acetatis...................................unciam unam-
Of Acetate of Potassium.............................one drachm.
Liquoris Ammonii Acetatis..............drachmas tres cum semisse.
Of Solution of Acetate of Ammonium........three and a half drachms.
Spiritus Ętheris Nitrosi...........................drachmas duas.
Of Spirits of Nitrous Ether...........................two drachms.
Infusi Buchu..........(quantum, sufficiat usque) ad uncias quattuor.
Of Infusion of Buchu (a quantity sufficient) up to four ounces.........
Misce. Fiat mistura. Signa: -Mix. Let a mixture be made. Label: -
Drachmam unam ter in die post cibos.
One drachm three times a day after meals.
The grammatical form proves on examination not to be a difficult one. The verb "recipe" which is invariably used, governs the accusative. It is clear that the pharmacist is not to take all of his stock of any ingredient but only a part thereof. Hence the nouns expressing the quantity, "un-ciam" "drachmas" are in the accusative governed by "recipe." The names of the ingredients of which the stated quantities are to be taken are in the partitive genitive. Adjectives must agree with the noun that they modify in gender, number, and case; so "duas" and "tres" agree with "drachmas," "unam" with "unciam," and "quattuor" though indeclinable with "uncias." "Nitrosi" also agrees with Ętheris. Potassii is again in the partitive genitive as are both "Ammonii" and "Acetatis" in the following line.
The last line of the inscription gives slightly more trouble. As usually written the words included within brackets are omitted, yet the clause beginning with "quantum" is the object of the sentence and is governed by the verb "recipe." "Infusi" is again in the partitive genitive. "Quantum" is in the accustive for the reason given; "sufficiat" is the third person singular of the present subjunctive owing to the clause being a subordinate one; "usque" is an adverb meaning "upto" "until"; "ad" a preposition governing the noun "uncias." There is a slightly different form in which this line is occasionally written in which in place of "Infusi" "Infusum" would be written; this is the partitive use of the accusative.