Copyright © 2015 Cengage Learning® Chapter 15 Urinary System Drugs.

Copyright © 2015 Cengage Learning®

Chapter 15Urinary System Drugs


Introduction• The following slides discuss various

urinary system drugs– Refer to the chapter for specific uses, side

effects, contraindications, and interactions

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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

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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

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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

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Diuretics (cont’d.)• Osmotic agents (e.g., mannitol)

– Most frequently used to reduce intracranial or intraocular pressure

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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

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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

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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

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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

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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

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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”

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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

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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

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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

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• 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

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• 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

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Copyright © 2015 Cengage Learning® Chapter 15 Urinary System Drugs.

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