A treatise on prescription incompatibilities and difficulties, including prescription oddities and curiosities for pharmacists and physicians and students in pharmacy and medicine

Front matter

Class KV\\ i< S

Book ZRb

Copyright^

Preface

FRANKNESS demands the statement that the subject of Prescription Incompatibilities is of considerably less importance now than it was twenty or thirty years ago. It was a rare day then when an editor of a pharmaceutical journal or one who was considered an expert in solving incompatible riddles did not receive orally or in writing a despairing call for help from some sorely puzzled druggist, who in attempting to put up a prescription as written by the doctor, got an unsightly, impossible mass, a strange, unlooked-for color, or perhaps a dangerously explosive mixture. And pharmaceutical journals devoted a good deal more space than they do now answering the "incompatible" queries of their subscribers. The flood of new remedies and synthetics was then at its height and the physician still unweaned from his habit of polypharmacal prescribing insisted on joining together things which the spirits of chemistry, pharmacy and therapeutics intended should be kept asunder. The idea at that time was still pretty general that the value of a prescription increased in direct ratio to the number of its ingredients. And the result was — not infrequently — a spoiled, useless, ludicrous, or even dangerous combination. Things are different now. Our propaganda during the past twenty-five years in favor of simple rational prescriptions has borne fruit. The modern physician does not believe in shotgun prescriptions; he prescribes one, seldom more than two or three active ingredients in a prescription. In fact, the tendency is now towards the other extreme : single remedies is the slogan, the physician thus not infrequently depriving himself of valuable synergistic or corrective combi-

6 PREFACE

nations. Of course, the fewer the ingredients in a prescription, the fewer the chances for incompatible combinations or impossible absurdities.

Nevertheless, the days of incompatible prescriptions and questionable combinations are not entirely over. Not as often as formerly, but still often enough is the author appealed to to clear up difficult points in physicians' prescriptions, and it is lack of time, and not lack of opportunity, that prevents him from playing the role of oracle on incompatibilities to the pharmaceutical profession. No, the subject of incompatibilities has not yet altogether lost its importance. And every intelligent pharmacist as well as every self-respecting and conscientious physician should be on terms of familiarity with the salient facts of prescription writing,, so that the latter may avoid and the former correct glaring absurdities.

It is just a quarter of a century since the author began to teach and to write on the subject of this book. His first Treatise on Prescription Incompatibilities and Difficulties appeared in Merck's Report, where it ran for several years. In a revised form it was published in The Critic and Guide for 1903, 1904 and 1905. It is not a mere phrase to state that the Treatise met with exceptional favor. It was claimed that the author was the only writer in the field who succeeded in making a dreary and dry-as-dust subject readable and interesting. And being interesting, the subject became memorizable ; it left an impression on the tablets of one's memory, which a dreary, non-interesting subject rarely does. The requests to reprint the Treatise in a separate volume were quite numerous — but then a busy practice and other, more interesting literary work made compliance with the request a practical impossibility. And with each year that passed the Treatise became more inadequate — because new remedies came into use and with them new incompatibilities, and the composition of certain pharmacopeial galenicals became changed, so that explanations and criticisms which

PREFACE 7

held good before, held good no longer. To bring the Treatise on Prescription Incompatibilities up to date required considerable additions, a few eliminations and a thorough revision. I despaired of ever having the time to devote to it.

But I recently achieved some leisure and I have taken the opportunity to subject the Treatise to a thorough revision and to bring it up to date. And I now take pleasure in presenting this enlarged and revised Treatise on Prescription Incompatibilities and Difficulties, including Prescription Oddities and Curiosities, to my friends in the pharmaceutical and medical professions.

A word on the kind of prescriptions and incompatibilities that are discussed in this Treatise. They are bona fide prescriptions and combinations, and the incompatibilities are such as have presented themselves to some druggists and physicians and are apt to present themselves again to others. It is not only superfluous and unnecessarily space-consuming, but it is mind-confusing and discouraging to present incompatibilities in prescriptions which never happened and never could happen, because no physician in his wildest flights of fancy would ever think of writing such combinations.

Let me illustrate by some examples: Of what use is it to tell a physician or a pharmacist, or a medical or pharmaceutical student, that mucilage of acacia is precipitated by sodium phosphomolybdate, that acetanilid gives a white precipitate with bromine, that meconic acid gives a precipitate with barium chloride, that urethane give off some ammonia when heated with a solution of potassium or sodium hydroxide, that cadmium salts are precipitated by alkali carbonates and chromates, that gamboge with ammonia water gives a yellow colored solution, that a mixture of cocaine and calomel acquires a dark color if the fumes of hydrochloric acid are blown over it, that a solution of methylthionine hydrochloride is precipitated by potassium bichromate, that piperazine explodes when heated to a certain temperature with sodium hypochlorite, that potassium salts give

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a yellow precipitate with platinic chloride and hydrochloric acid, that sugar is decomposed with ignition by concentrated sulphuric acid, that thymol is incompatible with chromic acid, etc., etc. — the list could be extended indefinitely.

It is not merely superfluous, but, as stated above, is confusing and discouraging to the student. For, seeing that most drugs have dozens and some even hundreds of incompatibilities, he loses courage and despairs of ever mastering the subject. Why, many of the chemicals given as incompatibles of this, that and the other thing are not even medicinal preparations, are never used in medicine, are never prescribed and consequently can never form the subject of prescription incompatibilities! Who ever heard of a doctor prescribing acacia with sodium phosphomolybdate, acetanilid with bromine (elementary bromine!) ? And of what interest is it to a student of incompatibilities to know that meconic acid is incompatible with barium chloride ? Have the two ever been prescribed? And has a doctor ever prescribed sugar with concentrated sulphuric acid? Or has anybody ever ordered to blow the fumes of HC1 over a mixture of cocaine and calomel? And so on. So what is it all for? The examples I have enumerated are chemical tests and reactions — they are useful in their place, but they have nothing to do with the subject of incompatibilities. This book will be found free from the superfluities referred to, and will, it is hoped, be found more acceptable and more useful on that account.

W. J. R.

12 Mount Morris Park West