NURS 1950: Pharmacology

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Objective 1: list two (2) major physiological functions of the kidneys

Objective 2: list the four (4) processes carried out by the nephron

Objective 3: name the part of the nephronresponsible for each of the processes

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Objective 4: name the pituitary hormone that influences the urine volume

Objective 5: name the adrenocorticalhormone that influences the urine volume

Objective 6: list the four (4) ways in which fluid is normally lost from the body

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Objective 7: describe the actions of diuretics

Diuretics act to

Deplete blood volume

Excrete sodium

Vasodilate peripheral arterioles (how is unknown)

Diuretics work in the kidney at various sites of the nephron

Can interfere with the action of aldosterone causing loss of sodium◦Where goes sodium, so goes water

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What happens with diuretics◦Decrease excess water◦Loop diuretics + 0.9% NaCl = loss of calcium

◦Decrease excess NaCl◦Decrease cerebral edema (Mannitol)

◦Decrease increased IOP (Diamox)

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Mannitol is an osmotic diuretic (a sugar); ◦in the brain, its presence causes water to be drawn to it

Works the same way in the eye: ◦the excess intraocular fluid is drawn to the mannitol in the hyperosmotic plasma

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◦Diamox very weak diuretic Useful in treating glaucoma

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◦Aminophylline◦Theophylline◦Caffeine◦Theobromine Diuretic effect from improved blood flow to kidney

Generally not used for diuretic effect

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Action of the thiazides◦ Act on the distal tubules of the kidney

Block reabsorption of sodium and chloride ions from the tubule

The unreabsorbed Na and Cl ions pass into the collecting ducts, taking water with them

Thiazides have antihypertensive properties because of direct vasodilation effect on peripheral arterioles◦ Expected outcomes from treatment

Decreased edema and improvement of symptoms RT excess fluid accumulation

Reduction in BP

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Assessments◦Mental status◦Diabetics require baseline blood glucose◦Assess hearing◦Assess for symptoms of acute gout

SE to expect: orthostatic hypotension◦Usually in initial stages of treatment◦Teach client safety measures

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SE to report◦GI irritation, N/V, constipation◦Electrolyte imbalance, dehydration◦Hyperuricemia ◦Hyperglycemia◦Hives, rash

Thiazides can interact with◦Digoxin, corticosteroids◦Lithium, NSAIDs◦Oral hypoglycemic agents

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Thiazides can interact with◦Digoxin, corticosteroids◦Lithium, NSAIDs◦Oral hypoglycemic agents

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Thiazide diuretics include◦Bendroflumethiazide (Naturetin)◦Chlorothiazide (Diuril)◦Hydrochlorothiazide (HCTZ) {Esidrix, HydroDiuril}

◦Polythiazide (Renese)◦Trichlomethiazide (Naqua, Metahydrin, Diurese)

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Thiazide-like drugs include◦Chlorthalidone (Hygroton)◦Indapamide (Lozol)◦Metolazone (Zaroxolyn)

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Drugs that affect the loop of Henle◦Bumetanide (Bumex)◦Ethacrynic acid (Edecrin)◦Furosemide (Lasix)◦Torsemide (Demadex)

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Act in the loop of Henle in the kidney◦Inhibits Na and Cl reabsorption

Some increase blood flow to glomeruli

Inhibits electrolyte absorption in proximal tubule◦Lose sodium, chloride, potassium, magnesium, sodium bicarbonate

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Onset of diuretic effect varies, but is within 1-2 hours. IV, drugs work within 5-10 minutes

Peak effect within 1-2 hoursDuration approximately 6 hours

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Maximum mg/day◦ Bumex 10 mg per 24 hours◦ Edecrin 400 mg per 24 hours◦ Lasix 1000 mg/24 hours

Cross sensitivities◦ Sulfonamides and Lasix, Demadex

SE to expect◦ Oral irritation◦ Dry mouth◦ Orthostatic hypotension

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SE to report with loop diuretics◦ GI irritation, abdominal pain◦ Electrolyte imbalance, dehydration◦ Hives, pruritus, rash◦ Some can cause loss of hearing and

hyperglycemia (interfere with hypoglycemic agents)

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Drug interactions◦Alcohol, barbiturates, narcotics◦Aminoglycosides◦Cisplatin ◦NSAIDs◦Corticosteroids◦Probenecid◦Digoxin

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Loop diuretics include◦Bumetanide (Bumex)◦Ethacrynic acid (Edecrin)◦Furosemide (Lasix)◦Torsemide (Demadex)

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Why is there concern about the electrolyte balance?

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Weak antihypertensives Mechanism of action unknown Do work in distal renal tubule

◦Retains potassium◦Excretes sodium◦Some have anti-aldosterone activity

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Maximum dosing per 24 hrs◦ drug dependent

SE to expect with Midamor: ◦anorexia, N/V, flatulence and HA

SE to report: ◦electrolyte imbalance, dehydration,

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SE to expect and report with Aldactone and Dyrenium: ◦mental confusion, HA, diarrhea, electrolyte imbalance, dehydration, gynecomastia, reduced libido, breast tenderness

Dyrenium can also cause allergic reaction (hives, pruritus, rash)

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Generally, drug interactions for the K+ sparing agents◦ Lithium, ACE inhibitors, salt substitutes, K+

replacement◦ NSAIDs,

Potassium-sparing drugs include◦ Amiloride (Midamor)◦ Spironolactone (Aldactone)◦ Triamterene (Dyrenium)

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Potassium-sparing drugs include◦Amiloride (Midamor)◦Spironolactone (Aldactone)◦Triamterene (Dyrenium)

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Why is an adequate fluid intake important with diuretic therapy?

If the client has to get up during the night to void, what will they probably do?

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What are some good dietary sources of potassium?

If a client is on Aldactone, what would you tell them about high potassium foods?

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Assessments to make

Teaching to include:

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Drugs include ◦Antibiotics Fosfomycin (Monurol) Quinolones : cinoxacin, nalidixic acid, norfloxacin

Methenamine madelate Nitrofurantoin

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Fosfomycin (Monurol)◦ Inhibits bacterial cell wall synthesis◦ Reduces adherence of bacteria to epithelial

cells of urinary tract◦ Single dose therapy

SE to expect: ◦ nausea, diarrhea, abdominal cramps, flatulence

SE to report: ◦ perineal burning, dysuria

Indicates UTI is not responding to treatment Drug interactions

◦ Drugs such as metoclopramide that increase GI motility

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Norfloxacin (Noroxin) has wide range of activity against gram negative and gram positive bacteria Expensive Reserve for resistant/recurrent infections

SE to report◦ Hematuria as crystals can form in urinary tract◦ HA, tinnitus, dizziness, tingling sensations,

photophobia

Various drug interactions can occur◦ Assess client’s current drug therapy, monograph

of quinolone being used

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◦ Converts to ammonia and formaldehyde in acidic urine◦ Used in clients susceptible to chronic, recurrent UTIs◦ Preexisting infections treated with antibiotics

Implementation ◦ DO NOT crush the tablets◦ pH testing of urine: report over 5.5

SE to expect ◦ N/V, belching

SE to report◦ Hives, pruritus, rash◦ Bladder irritation, dysuria, frequency

Drug interactions◦ Acetazolamide, sodium bicarbonate◦ Sulfamethizole

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◦ Interferes with several bacterial enzyme systems◦ Effective only in the urinary tract

SE to expect: ◦ N/V, anorexia, urine discoloration

SE to report:◦ Dyspnea, chills, fever, erythematous rash, pruritus◦ Peripheral neuropathies ◦ Second infection

Drug interactions◦ Magnesium containing products can decrease

absorption

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Bethanecole chloride (Urecholine) Neostigmine (Prostigmin) Oxybutynin chloride (Ditropan) Phenazopyridine (Pyridium) Tolterodine (Detrol)

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◦ Parasympathetic nerve stimulant◦ Causes contraction of detrusor urinae muscle

Results in urination May also stimulate gastric motility Can increase gastric tone Can restore impaired rhythmic peristalsis

SE to expect◦ Flushing of skin, HA

SE to report◦ N/V, sweating, colicky pain, abdominal cramps◦ Diarrhea, belching, involuntary defecation

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◦ Anticholinesterase agent◦ Binds to cholinesterase

Prevents destruction of acetylcholine Effects are: miosis; increased tone of

intestinal, skeletal, and bladder muscles Bradycardia; stimulation of secretions of

salivary and sweat glands Constriction of bronchi and ureters

Neostigmine used to prevent and treat postoperative distension and urinary retention◦ Assess for pregnancy, intestinal or urinary

obstruction, peritonitis◦ Assess coronary status

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Antispasmodic agent—acts directly on smooth muscle of the bladder◦Delays initial urge to void◦Do not use if glaucoma, myasthenia

gravis, ulcerative colitis, obstructive uropathy

SE to expect◦Dry mouth, urinary hesitance, retention◦Constipation, bloating◦Blurred vision Report any SE that are intensified

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Produces local anesthetic effect in urinary tract

Acts about 30 min. after administration Used to relieve burning, pain, urgency,

frequency in UTI Reduces bladder spasms

SE to expect◦ Reddish-orange urine color

SE to report◦ Yellow sclera or skin

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Muscarinic receptor antagonists Inhibit muscarinic action of acetylcholine on

bladder smooth muscle Used to treat overactive bladder Do not use if glaucoma, ulcerative colitis,

obstructive uropathy S/E to expect

◦ Dry mouth◦ Urinary hesitance, retention◦ Constipation, bloating◦ Blurred vision◦ Report if the effects intensified

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Objective 18: Discuss patient education guidelines for drugs that affect the urinary system

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Objective 19: identify at least one nursing diagnosis that may be applicable for clients receiving diuretic therapy under the guidance of the instructor

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