Copyright © 2015 Cengage Learning® Chapter 15 Urinary System Drugs

Copyright © 2015 Cengage Learning® Introduction The following slides discuss various urinary system drugs –Refer to the chapter for specific uses, side effects, contraindications, and interactions 2

Copyright © 2015 Cengage Learning® Diuretics Most commonly used drugs influencing function of the urinary tract –Main indication is to reduce circulating fluid volume to help treat edema and hypertension Five categories –Thiazides, loop diuretics, potassium-sparing diuretics, osmotic agents, and carbonic anhydrase inhibitors 3

Copyright © 2015 Cengage Learning® Diuretics (cont’d.) Thiazides –Most frequently used diuretic Increase excretion of water, sodium, chloride, and potassium Loop diuretics –Act directly on the loop of Henle in the kidney Inhibit sodium and chloride reabsorption; inhibits water reabsorption back into the bloodstream; leads to increased urine formation 4

Copyright © 2015 Cengage Learning® Diuretics (cont’d.) Potassium-sparing diuretics –Sometimes administered under conditions in which potassium depletion can be dangerous –May counteract increased glucose and uric acid levels associated with thiazide diuretic therapy –Seldom used alone 5

Copyright © 2015 Cengage Learning® Diuretics (cont’d.) Osmotic agents (e.g., mannitol) –Most frequently used to reduce intracranial or intraocular pressure 6

Copyright © 2015 Cengage Learning® Medications for Gout What is gout? –A form of arthritis and a metabolic disorder Characterized by accumulation of uric acid crystals in various joints, tissues, and sometimes the kidneys, with resultant inflammation and pain Management includes treating acute attacks, uric acid-lowering therapy, and preventing recurrence of acute attacks Onset of acute gout is characterized by sudden onset of pain, redness, warmth, and swelling in the affected joints 7

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Medications for Gout (cont’d.) Non-steroidal anti-inflammatory drugs (NSAIDs) and colchicine –NSAIDs work quickly to relieve pain when started soon after symptom onset –Colchicine is used to relieve inflammation in acute gouty arthritis and in chronic management of gout 9

Copyright © 2015 Cengage Learning® Medications for Gout (cont’d.) Uricosuric agents –Act on the kidney by blocking reabsorption and thereby promoting urinary excretion of uric acid –Used in treatment of chronic cases of gout and frequent disabling attacks of gouty arthritis No analgesic or anti-inflammatory activity and not effective in treatment of acute gout 10

Copyright © 2015 Cengage Learning® Medications for Gout (cont’d.) Xanthine oxidase inhibitors allopurinol –Used to treat chronic gout Results in decreased serum and urinary levels of uric acid No analgesic or anti-inflammatory activity and not effective in treatment of acute gout 11

Copyright © 2015 Cengage Learning® Bladder Antispasmodics What is overactive bladder (OAB)? –Condition characterized by two urinary symptoms: frequency and urgency Antispasmodics are used to increase capacity, decrease urgency of the urinary bladder, decrease bladder tone, and suppress bladder contractions in patients with neurogenic bladder resulting in decreased incontinence 12

Copyright © 2015 Cengage Learning® Cholinergics Bethanechol (Urecholine) is a cholinergic drug –Stimulates parasympathetic nerves to bring about contraction of the urinary bladder in cases of nonobstructive urinary retention Usually used postoperatively or postpartum “Pharmacological catheterization” 13

Copyright © 2015 Cengage Learning® Urinary Analgesics Phenazopyridine (Pyridium) is an oral urinary analgesic or local anesthetic for urinary tract mucosa –Used short-term to relieve burning, pain, discomfort, and urgency associated with cystitis (bladder inflammation) –Used only for symptomatic relief 14

Copyright © 2015 Cengage Learning® Treatment of Benign Prostatic Hyperplasia Benign prostatic hyperplasia (BPH) is the most common benign tumor in men –Involves hyperplasia leading to prostate enlargement that interferes with urination flow Drugs used to treat symptoms slow prostate growth and relax the bladder smooth muscle to make it easier for urine to flow from the bladder through the urethra 15

Copyright © 2015 Cengage Learning® Treatment of Benign Prostatic Hyperplasia (cont’d.) Antiandrogens –Finasteride and dutasteride work by suppressing prostate growth Used to reduce prostate size and associated urinary obstruction and manifestations Appears to be suppressive rather than curative, and return of the hypertrophy is likely if the drug is withdrawn 16

Copyright © 2015 Cengage Learning® Treatment of Benign Prostatic Hyperplasia (cont’d.) Alpha-blockers –Tamsulosin (Flomax) blocks alpha-1 receptors found in smooth muscle in the bladder neck and prostate, causing them to relax Urine flow rate is improved and the symptoms of BPH are decreased –First-line therapy for the treatment of BPH 17

Copyright © 2015 Cengage Learning® Treatment of Benign Prostatic Hyperplasia (cont’d.) Phosphodiesterase (PDE) inhibitor –Tadalafil (Cialis) is a PDE inhibitor approved for the treatment of erectile dysfunction Recently approved to treat the signs and symptoms of BPH 18