USUAL DOSE.— The greatest use is in the oral form in prolonged therapy when no difficulty in swallowing is present. It varies from 15 to as much as 375 mg per day. The average dosage is 150 mg given over 24 hours.
Bethanechol Chloride (Urecholine, Duvoid)
ACTION AND USE.— This drug is used for acute postoperative and postpartum nonobstructive urinary retention and neurogenic atony of the urinary bladder with retention.
USUAL DOSE.— Orally, give 10 to 50 mg two to four times daily; maximum dose is 120 mg. Parenterally, SUBCUTANEOUSLY ONLY, give 5 mg.
Pilocarpine (Pilocar, Isopto-Carpine)
ACTION AND USE.— Pilocarpine decreases intraocular pressure in glaucoma.
USUAL DOSE.— Initially, instill 1 drop into the eye, up to six times daily. The average dose is 1 drop two to four times daily.
Parasympatholytic Drugs (Anticholinergic Drugs)
These drugs oppose the effect of impulses conveyed by the parasympathetic nerves. They act as competitive inhibitors of acetylcholine; they relax smooth muscles and inhibit secretions of duct glands.
Atropine Sulfate (Alkaloid obtained from Belladonna)
ACTION AND USE.— There are two major actions: (1) On the central nervous system, it causes an increase in respiration; and (2) on the smooth muscles and secretory glands, it relaxes the muscles of the intestinal tract, bronchi, ureter, biliary ducts, and gallbladder. It inhibits glandular secretions, causing dryness of the nose, throat, bronchi, mouth, and skin.
Atropine has a mydriatic effect on the pupil of the eye and causes a paralysis of accommodation. Atropine is used as a mydriatic and cycloplegic in ophthalmology, as an anhydrotic (checking the secretion of sweat), in large doses as a circulatory stimulant, and as a respiratory stimulant in certain poisonings. It is a physiologic antidote for neostigmine, pilocarpine, nerve gases, and other parasympathomimetics. Atropine may be given with morphine to overcome the respiratory depressant effects of morphine. It is used preoperatively to reduce salivary and bronchiole secretions.
USUAL DOSE.— For ophthalmic purposes, instill 1 or 2 drops into the eye(s) up to three times daily or 1 hour prior to examination. Orally and parenterally for other indications, give 0.4 to 0.6 mg as directed by a physician.
Propantheline Bromide (Pro-Banthine)
ACTION AND USE.— This drug is used as adjunctive therapy in the treatment of peptic ulcer by reducing the volume and the acidity of gastric secretions. It is also used as an antispasmodic in the treatment of intestinal spasms and in spasms of the ureter and bladder.
USUAL DOSE.— 15 mg taken 30 minutes before meals and 30 mg at bedtime.
Glycopyrrolate (Robinul)
ACTION AND USE.— Glycopyrrolate is also used as adjunctive therapy in the treatment of peptic ulcer. It is also indicated for intramuscular or intravenous use in conjunction with anesthesia.
USUAL DOSE.— Orally, give 1 mg three times daily or 2 mg two or three times daily. Parenterally, give 0.002 mg/pound intramuscularly 30 minutes to 1 hour prior to anesthesia.
Sympathomimetic Drugs
These drugs stimulate the structures controlled by the sympathetic (or adrenergic) nerves and start adrenal medullary discharge of epinephrine. The two main drugs, epinephrine and phenylephrine are discussed under the vasoconstrictive drugs earlier in this chapter.
Sympatholytic Drugs
Also called adrenergic blocking agents, these drugs block the action of the sympathomimetic amines or block sympathetic outflow. The alpha-adrenergic blocking agents block the vasoconstricting effects of epinephrine and norepinephrine, thereby lowering the blood pressure. The beta-adrenergic blocking agents block the cardiac
