GROUP

See also:

• XXVIII

XXVIII  . Sugars, Starches, Gums, Gelatin, &c.—Although these and allied bodies are used in various ways as remedies, their action is for the most part purely mechanical or dietetic . (R . S.*) Terminology in Therapeutics . It may be useful to give here a general explanation of the common names used in the therapeutic classification of drugs . It is convenient to divide drugs and other substances used in medicine into groups according to the part of the system on which they chiefly act, though, as stated above, many drugs act in more than one manner and could come under several groups . I . Drugs acting on the blood vessels, which either dilate the vessels when taken internally or applied locally, or contract the superficial arterioles . Irritants (Lat. irritare, to excite) include: Rubefacients (Lat. rubefacere, to make red), which cause the skin to become red from dilatation of the blood vessels; Vesicants (Lat. vesica, a bladder), which irritate sufficiently to cause the blood-serum to exude and form vesicles or blisters, e.g. cantharides; Pustulants (Lat. pustula, a blister), still more powerful in their effects, causing the blisters to become filled with pus, e.g. croton oil . Escharetzcs (Gr . Eax6.pa, hearth, brazier; hence mark of a burn, " scar ") or Caustics (Gr . Kalete, to burn), cause the death of the part, e.g. silver nitrate and nitric acid .

The

term counter-irritant is used when an irritant is applied to the skin for the purpose of relieving pain or congestion by dilating the superficial vessels . Drugs which contract the vessels and diminish exudation comprise Astringents (Lat. astringere, to draw close), while Styptics (arCsety, to contract) or Haemostatics (Gr. aTua, blood, arariebc, causing to stand) are substances applied either locally or internally in order to arrest bleeding; cold, adrenalin, ergot and the per-salts of iron may be taken as examples . II . Drugs acting on the digestive tract . Sialogogues (Gr. elaXov, spittle, ttywybs, leading) increase the flow of saliva, e.g. mercury; Antisialogogues decrease the flow, e.g. belladonna . Aromatic: (Gr. dpwua, spice) or Bitters increase the flow of the gastric juice . Stomachics (Gr. aroµaxos) have the same effect . The term Carminatives (Lat. carminare, to card wool), adopted from the old medical theory of humours, is generally applied to pungent substances which help to expel gas from the stomach by stimulating the movement of its contents . Emetics (Gr. gaeros, vomiting) are substances given for the purpose of causing vomiting, e.g. ipecacuanha or apomorphine . Anti-emetics or Sedatives (Lat. sedare, to compose) arrest vomiting either by their central or local action, e.g. opium, cocaine or cerium oxalate . Purgatives (Lat. purgare, to cleanse) aid the onward passage of the contents of the intestinal canal, either by increasing the contractions of its muscular coat as laxatives (Lat. laxare, to loosen), e.g. as magnesia, or by increasing the flow of fluid . Some are termed drastics (Gr .

SpaoriK6s, active) or cathartics (Gr . KaBaprie6s, cleansing), which produce watery evacuations . Cholagogues (Gr. xoart, bile, ayoybs, leading) are purgatives which act by increasing the flow of bile, either by causing an increased secretion (e.g. podophyllum) or by sweeping it onwards by stimulating the intestinal contractions (e.g.

calomel) . IV . Drugs acting on the urinary system . Diuretics (Gr . &a, through, ovpoe, the urine) increase the flow of urine, while lithontriptics (Gr . XLBos, stone, rpifecv, to rub, grind down) are drugs given to prevent the formation of urinary calculi . V . Drugs acting on the generative system . Aphrodisiacs (Gr . 'AttipoSir,t, the goddess of love) increase the action of the generative centre in the spinal cord; Anaphrodisiacs decrease its action .

Ecbolics (Gr . EK$aXXecv, to throw out) or oxytocics (Gr . OV/s,

sharp, quick, r6Kos, parturition) stimulate uterine action . Emmenagogues (Gr . Eµµrtva, menses, ayuyos, leading) are substances which increase the menstrual flow . Galactogogues (Gr. yaaa, milk) in-crease the secretion of milk, while antigalactogogues (e.g. belladonna) have the opposite effect . VI . Drugs acting on the respiratory system . Expectorants increase the bronchial secretions; antispasmodics relax the spasm of the muscular coat of the bronchial tubes, e.g. stramonium . This latter term is also used for drugs which act as general depressants . IX . Drugs acting on metabolism .

Alteratives are drugs which alter the course of a disease, the mode of action being unknown . Tonics are drugs which increase the muscular

tone of the body by acting either on the stomach, heart, spinal cord, &c . X . Drugs acting on the blood . Antitoxins are organic products designed to neutralize the formation of the toxins of certain diseases in the blood . Toxins are also injected in order to stimulate the blood plasma to form antitoxins (see BACTERIOLOGY) . Antiperiodics inhibit a disease having periodic recurrences; e.g. quinine in malaria . Haematinics are drugs which increase the amount of haemoglobin in the blood . XI . Drugs acting on the nervous system . Anaesthetics (q.v.) diminish sensibility, either central or peripheral; Anodynes (Gr. av-, priv., 6Sutnt, pain) relieve pain only, but, as in Analgesics (Gr. iilyriais, sense of pain), sensibility is unaltered . Stimulants are those which lead to excitation of the mental faculties and in quantity may lead to delirium and incoherence .

Hypnotics (Gr. virvos,

sleep) or Soporifics (Lat. sopor, a deep sleep) are drugs which produce sleep without causing cerebral excitement . Narcotics (Gr. vapKrt, numbness) are those which besides producing sleep may in large doses depress the functions of respiration and circulation . XI I . Drugs which arrest the progress of putrefaction . This is either by inhibiting the growth of micro-organisms (Antiseptics) or by destroying them when present (Disinfectants) . (H . L .