Incompatibility in prescriptions and how to avoid it : to which is added a dictionary of incompatibilities / by Thomas Stephenson.

  • Stephenson, Thomas, 1864-1938.
Date:
1929
Catalogue details

Licence: In copyright

Credit: Incompatibility in prescriptions and how to avoid it : to which is added a dictionary of incompatibilities / by Thomas Stephenson. Source: Wellcome Collection.

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    And How to Avoid It PART I—GENERAL PRINCIPLES OF INCOMPATIBILITY INCOMPATIBILITY has been defined as ‘any uninten- tional change which notably interferes with the elegance, usefulness, or safety of a prescription.’1 Such changes may belong to one of three classes: (i) chemical ; (2) physical or pharmaceutical; (3) therapeutic. 1. Chemical Incompatibility Where the ingredients of a prescription interact chemically in the circumstances described above, that is, when such chemical action is not intentional, and interferes with the elegance, usefulness, or safety of the medicine, the prescription is said to be chemically incompatible. This may occur when : (a) An insoluble compound is precipitated. (b) Gas is evolved. {c) An acid and an alkaline substance are mixed. (d) One of the ingredients is decomposed. (e) An alkaloid is precipitated. (/) An undesirable compound is formed. (a) An Insoluble Compound is Precipitated.—It is a recognized principle in chemistry that solutions of two soluble salts will invariably yield a precipitate when by mutual decom- position an insoluble salt can be formed, the tendency being always to revert to the more stable form. The salts most likely to be met with in prescribing that readily form such insoluble compounds are those of calcium, magnesium, iron, mercury, lead, zinc, and silver. Calcium and Magnesium.—The soluble salts of calcium (chloride and bromide) give a precipitate with alkaline hydroxides, carbonates, sulphates, and phosphates. Aromatic spirit of ammonia is thus incompatible with calcium chloride. 1 Walter G. Smith : Incompatibility and Some of its Lessons (1911).