Spoons, glasses and cups vary so much in capacity that it is never safe to prescribe solutions of powerful drugs to be measured by them. The use of glass graduates, which can be obtained accurately marked, should be insisted upon. PHARMACOPOEIAL PREPARATIONS AND THEIR DOSES. Most drugs are not, in their natural state, suitable for administration. They are either too bulky, too nauseous, or contain noxious principles. Preparations suitable for administration are, therefore, prepared from them according to "official" pharmacopœial directions. The doses of the various official drugs and their preparations which may safely be given to an adult are taken from the last edition of the United States Pharmacopoeia. These doses are intended to be "the average approximate (but neither a minimum nor a maximum) dose for adults." But these doses are often not rigorously adhered to in prescribing, because they vary with the purpose for which the drug is required and the age of the patient. The following is an account of the preparation of the pharmacopoeial preparations, and the attempt has been made to arrange the doses so as to make them easy of remembrance. Unless otherwise specified, the preparations are for internal use. Aceta (Vinegars).—Liquid preparations resulting from the extraction of the drug with dilute acetic acid, and filtering. The U. S. P. contains two. Acetum Opii Acetum Scillæ Aqua (Waters).—Preparations made by impregnating water with a volatile substance. Mostly made by triturating the substance with purified talc and filtering. Those in the U. S. P. thus made are Cataplasmata (Poultices).-Soft, pasty masses used as a medium for the external and local application of a moist heat, with or without the addition of active medicaments. Any bland substance which will retain its heat and moisture for a long time is applicable for this purpose, a little oil or glycerin being often added to prevent caking. The substances chiefly used are flax-seed, elm bark, bread and milk, bran, and oatmeal. To make a poultice properly, the bowl in which it is mixed, the water, the spatula for mixing and spreading the flannel or cheese-cloth on which it is laid, must all be as hot as possible. The meal should be added gradually to the boiling water, which is continually stirred. It should not be spread so thick as to make it inconveniently heavy. One cataplasm is official in U. S. P.: Cataplasma Kaolini. Cerata (Cerates).-Adhesive preparations for external use, containing wax, capable of being spread at ordinary tempera tures, and not melting at the temperature of the body. Six are official in U. S. P. Ceratum Ceratum Cantharidis Ceratum Resina Compositum Chartæ (Papers).-Non-absorbent papers coated with plaster-like preparations and used like plasters. The U. S. P. contains one: Charta Sinapis, made from mustard. Collodia (Collodions).-Preparations for external use, either simple collodion, a solution of pyroxylin in ether and alcohol, or impregnated with an active substance. When applied externally a protective film is formed owing to the rapid volatilization of the solvent. The U. S. P. contains four: Collodium. Confectiones Collodium Cantharidatum. (Confections).-Synonym.-Electuaries. In England also called Boluses or Conserves. Permanent pasty preparations of powdered drugs thoroughly triturated with syrup or honey. The U. S. P. contains two: Confectio Rosæ, used as a basis for pills. Decocta (Decoctions).-Liquid preparations of organic drugs, coarsely comminuted, 5 grammes of drug to 1000 c.c. of decoction unless otherwise specified by the physician or Pharmacopoeia; made by exhausting the drug by boiling in water, straining the resulting liquid, and adding sufficient cold water to secure the required ratio. The U. S. P. contains none. Decoctions should be freshly made, as they are liable to de compose. Elixira (Elixirs).-Sweet and aromatic liquid preparations, containing 20 to 25 per cent. of alcohol. There are three in the U. S. P.: Elixir Aromaticum, used for flavoring. -Adjuvans, used for flavoring. -Ferri, Quininæ, et Strychnine Phosphatum, Dose, 4 c.c.; 1 fl. dr. Emplastra (Plasters).-Tenacious preparations for external application, solid at ordinary temperatures, but pliable and adhesive at the temperature of the body. Those of the U. S. P. Emulsa (Emulsions).-Liquid preparations consisting of oily or resinous substances held suspended in water which has been rendered mucilaginous or viscid. Acacia and Tragacanth are frequently used to form emulsions. Acacia is incompatible with ferric chloride, borax, and lead subacetate. Emulsions are coagulated by acids, an undue proportion of metallic salts, and spirituous liquids. There are in U. S. P.: Extracta (Extracts).-Solid or soft-solid preparations not agreeing in strength, made by evaporating solutions of the active constituents of organic drugs to the required consistency. The drug is first powdered, then macerated and percolated with the appropriate menstruum to exhaustion. The first third of the percolate is reserved, the remainder is evaporated at a temperature not exceeding 50° C.; 122° F.; until its weight is ten per cent. of that of the drug used, then mixed with the reserved portion, and both are evaporated at or below the above-named temperature until an extract of a pilular consistence remains. For converting extracts into powdered extracts it is sometimes necessary to add an inert dry substance. The menstrua used are: (a) Alcohol: Extractum Cannabis Indicæ, Colocynthidis Compositum, and Physostigmatis. (b) Alcohol and water: Extractum Belladonna Foliorum, Ergotæ, Rhamni Purshianæ, and Taraxaci. (c) Diluted alcohol: Extractum Colocynthidis. (d) Water: Extractum Aloes, Gentianæ, Hæmatoxyli, Krameriæ, Opii, and Quassiæ. (e) Water and Aqua Ammoniæ: Extractum Glycyrrhizæ Purum. (f) Acetic Acid and water: Extractum Colchici Cormi. (g) Acetic Acid, alcohol, and water: Extractum Nucis Vomicæ. Obtained by maceration and evaporation: Extractum Malti. Obtained by evaporating the fluidextract: Extractum Cimicifuge, Digitalis, Euonymi, Hyoscyami, Leptandræ, Rhei, Scopola, Stramonii, and Sumbul. |