Unit 12 Urinary Drugs2
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Transcript of Unit 12 Urinary Drugs2
Drugs that affect the Urinary System
Pharmacology
1
Renal Regulation: Obj 1• Kidneys regulate
– Fluid volume, electrolytes, acid-base balance• Kidneys secrete
– Renin- for blood-pressure regulation– Erythropoietin – to stimulate blood-cell
production– Calcitrol –active form of vitamin D for bone
hemeostasis
Kidney Structure• Urinary system consists of
– Two kidneys– Two ureters– One bladder– One urethra
• Objective 2: List the four processes carried out by the nephron.
• Objective 3: Name the part of the nephron responsible for each process.
4
Nephron• Nephron is functional unit of kidney• Blood enters nephron and is filtered through
Bowman’s capsule• Fluid is called filtrate• Water and small molecules pass into proximal
tubule
Nephron (continued)• Filtrate passes through loop of Henle, then
distal tubule• Filtrate empties into collecting ducts and
leaves nephron as urine
Reabsorption• Filtrate in Bowman’s capsule is same
composition as plasma minus large proteins• Some substances in filtrate cross wall of
nephron and reenter blood• Most of water in filtrate is reabsorbed• Glucose, amino acids, sodium, chloride,
calcium, and bicarbonate are reabsorbed
Secretion• Some substances pass from blood through
walls of nephron and become part of filtrate• Potassium, phosphate, hydrogen, ammonium
ion, and some acid drugs are secreted into filtrate
• Reabsorption and secretion are critical to pharmacokinetics of many drugs
Figure 30.1 The nephron
Renal Failure• Decrease in kidney’s ability to function
– Drugs can accumulate to high levels– Medication dosages need to be adjusted– Administering average dose to person in renal
failure can be fatal
Diagnosis of Renal Failure• Urinalysis• Serum creatinine• Diagnostic imaging• Renal biopsy
Diagnosis of Renal Failure (continued)
• Glomerular filtration rate (GFR)– Best marker for estimating renal function– Measure volume of water filtered per minute
Acute Renal Failure• Requires immediate treatment• Accumulation of waste products can be fatal• Most common cause is hypoperfusion
Acute Renal Failure (continued)• Cause must be rapidly identified
– Heart failure – Dysrhythmias– Hemorrhage– Dehydration
Chronic Renal Failure• Occurs over months or years• Usually history of diabetes mellitus or
hypertension• May be undiagnosed for a long time• Nephrotoxic drugs can cause acute or chronic
renal failure– See Table 30-1
Pharmacotherapy• Attempts to cure cause of dysfunction
– Diuretics to increase urine output– Cardiovascular drugs to treat hypertension or
heart failure– Dietary management
• Restriction of protein, reduction of sodium, potassium, phosphorus, magnesium
• Objective 4: pituitary hormone that influences urine volume:– ADH (Posterior pituitary)
• Objective 5: adrenocortical hormone that influences urine volume:– Aldosterone (increases Na+ reabsorption in the distal
tubule)
• Objective 6: four ways fluid is lost from the body– Urine, perspiration, lungs, stool
19
20
Objective 7: describe the actions of diuretics
1
Diuretics act to
Deplete blood volume
Excrete sodium
Vasodilate peripheral arterioles (how is unknown)
Diuretics• Increase rate of urine flow• Excretion of excess fluid used to treat
– Hypertension, heart failure, kidney failure– Liver failure or cirrhosis, pulmonary edema
Side Effects of Diuretic Therapy• Fluid and electrolytes disturbances
– Dehydration– Orthostatic hypotension– Potassium and sodium imbalances
• 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
24
• 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)
25
Mannitol is an osmotic diuretic (a sugar); ◦ in the brain, its presence causes water to be
drawn to itWorks the same way in the eye: ◦ the excess intraocular fluid is drawn to the
mannitol in the hyperosmotic plasma
26
Carbonic anhydrase inhibitor
– Diamox very weak diuretic• Useful in treating glaucoma
27
Methylxanthines
– Aminophylline– Theophylline– Caffeine– Theobromine
• Diuretic effect from improved blood flow to kidney
• Generally not used for diuretic effect
28
Objective 8: describe the uses, actions, and adverse effects of the thiazide and thiazide-like diuretics
• Drugs that affect the loop of Henle–Bumetanide (Bumex)–Ethacrynic acid (Edecrin)–Furosemide (Lasix)–Torsemide (Demadex)
29
Loop Diuretics
• 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
30
Loop Diuretics
• Onset of diuretic effect varies, but is within 1-2 hours. IV, drugs work within 5-10 minutes
• Peak effect within 1-2 hours• Duration approximately 6 hours
31
Loop Diuretics• 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
32
Loop Diuretics
• 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)
33
Loop Diuretics
• Drug interactions– Alcohol, barbiturates, narcotics– Aminoglycosides– Cisplatin – NSAIDs– Corticosteroids– Probenecid– Digoxin
34
Loop Diuretics
• Loop diuretics include– Bumetanide (Bumex)– Ethacrynic acid (Edecrin)– Furosemide (Lasix)– Torsemide (Demadex)
35
Loop Diuretics• Loop or high-ceiling are most effective
diuretics• Mechanism of action: to block reabsorption of
sodium and chloride in loop of Henle• Primary use: to reduce edema associated with
heart, hepatic, or renal failure• Furosemide and torsemide also approved for
hypertension
Loop (High-Ceiling) Diuretics• Obtain baseline and monitor periodically lab
values, weight, current level of urine output• Monitor electrolytes, especially potassium,
sodium, and chloride
Loop (High-Ceiling) Diuretics (continued)
• Monitor blood urea nitrogen (BUN), serum creatinine, uric acid, and blood-glucose levels
• Assess for circulatory collapse, dysrhythmias, hearing loss, renal failure, and anemia
Loop (High-Ceiling) Diuretics (continued)
• Monitor for side effects orthostatic hypotension, hypokalemia, hyponatremia, polyuria
• Observe for rash or pruritis• Teach clients to take diuretics in the morning,
change position slowly, monitor weight
Loop (High-Ceiling) Diuretics (continued)
• Clients should take potassium supplements, if ordered, and consume potassium–rich foods
Obj. 9 Thiazides• 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
42
Thiazides• 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
43
Thiazides• 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
44
• Thiazides can interact with–Digoxin, corticosteroids–Lithium, NSAIDs–Oral hypoglycemic agents
45
Thiazide and Thiazide-like Drugs
• Thiazide diuretics include– Bendroflumethiazide (Naturetin)– Chlorothiazide (Diuril)– Hydrochlorothiazide (HCTZ) {Esidrix,
HydroDiuril}– Polythiazide (Renese)– Trichlomethiazide (Naqua, Metahydrin,
Diurese)46
• Thiazide-like drugs include–Chlorthalidone (Hygroton)–Indapamide (Lozol)–Metolazone (Zaroxolyn)
47
Thiazide Diuretics• Largest, most commonly prescribed class of
diuretics• Mechanism of action: to block Na+
reabsorption and increase potassium and water excretion
• Primary use: to treat mild to moderate hypertension– Also indicated to reduce edema associated with
heart, hepatic, and renal failure
Thiazide Diuretics (continued)
• Less efficacious than loop diuretics– Not effective in clients with severe renal failure
Objective 11: list the electrolyte imbalance that most commonly occurs as a result of diuretic therapy
• Why is there concern about the electrolyte balance?
51
Obj. 12 Potassium-Sparing Diuretics
• Weak antihypertensives• Mechanism of action unknown• Do work in distal renal tubule
– Retains potassium– Excretes sodium– Some have anti-aldosterone activity
52
Potassium Sparing diuretics
• Maximum dosing per 24 hrs– drug dependent
• SE to expect with Midamor: – anorexia, N/V, flatulence and HA
• SE to report: – electrolyte imbalance, dehydration,
53
Potassium Sparing diuretics
• 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)
54
Potassium Sparing diuretics
• 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)
55
Potassium Sparing diuretics
• Potassium-sparing drugs include–Amiloride (Midamor)–Spironolactone (Aldactone)–Triamterene (Dyrenium)
56
Potassium-Sparing Diuretics
• Advantage: diuresis without affecting blood potassium levels
• Mechanism of action: either by blocking sodium or by blocking aldosterone
• Potassium-sparing diuretics shown in Table 30.5
Objective 13: explain how increased fluid intake enhances the action of diuretics
• 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?
58
Miscellaneous Diuretics• Cannot be classified as loop, thiazide, or
potassium-sparing agents• Three of these drugs inhibit carbonic
anhydrase• Primary use: to maintain urine flow in times of
hypoperfusion– For clients with acute renal failure or during
prolonged surgery
Role of the Nurse• Pharmacological management of renal failure
and diuretic therapy– Careful monitoring of client’s condition– Providing education relating to prescribed drug
management
Role of the Nurse (continued)• Obtaining medical, drug, dietary, and lifestyle
history• Assessment of client’s weight, intake/output,
skin turgor/moisture, vital signs, breath sounds, and presence of edema
Thiazide and Thiazide-like Diuretics
• Obtain baseline and monitor periodically lab values, weight, current level of urine output
• Measure electrolytes, especially potassium, sodium, and chloride, prior to loop-diuretic therapy
• Monitor blood urea nitrogen (BUN), serum creatinine, uric acid, blood-glucose levels
Thiazide and Thiazide-like Diuretics (continued)
• Increased potassium loss may occur when used with digoxin
• Increased risk of lithium toxicity when taking thiazide diuretics
• Allergies to sulfa-based medications can indicate hypersensitivity
• Use with caution in pregnant women• DO not administer to lactating women
Thiazide and Thiazide-like Diuretics (continued)
• Teach client to– Use sunscreen to decrease photosensitivity– Take potassium supplements, if ordered– Consume potassium-rich foods– Report any tenderness or pain in joints
Potassium-Sparing Diuretics• Advantage: client will not experience
hypokalemia• Critical to assess electrolytes (potassium and
sodium), blood urea nitrogen (BUN), serum creatinine
• Adverse effects : hyperkalemia, and GI bleeding, confusion, dizziness, muscle weakness, blurred vision, impotence, amenorrhea, gynecomastia
Potassium-Sparing Diuretics (continued)
• Spironolactone may decrease effectiveness of anticoagulants
• Clients taking lithium or digoxin may be at increased risk for toxicity
• Triamterene contraindicated for lactating women
• Report signs and symptoms of hyperkalemia
Potassium-Sparing Diuretics (Client Teaching)
• Avoid use of potassium-based salt substitutes• When in direct sunlight use sunscreen• Avoid performing tasks that require mental
alertness• Do not eat excess amount of foods high in
potassium
Loop Diuretics• Prototype drug: furesomide (Lasix); increases
urine output even when blood flow to kidney is diminished
• Mechanism of action : to block reabsorption of sodium in Loop of Henle
• Primary use: to treat hypertension and reduce edema associated with heart failure, hepatic cirrhosis, and renal failure
Loop Diuretics (continued)• Adverse effects: rapid excretion of large
amounts of water, dehydration and electrolyte imbalances ototoxicity
• Other examples– Torsemide: longer half life than furosemide; once-
a- day dosing– Bumetanide (Bumex): 40 times potency of
furosemide; shorter duration of action
Thiazide Diuretics• Prototype drug: chlorothiazide (Diuril)• Mechanism of action: to block sodium
absorption in distal tubule of nephron
Diuril
Thiazide Diuretics (continued)• Primary use: to treat mild to moderate
hypertension– To treat severe hypertension, in combination with
other drugs – To treat fluid retention from heart failure, liver
disease, corticosteroid or estrogen therapy• Adverse effects: dehydration, orthostatic
hypotension, hypokalemia
Potassium-Sparing Diuretics• Less effective than loop diuretics but help
prevent hypokalemia• Prototype drug : spironolactone (Aldactone)• Mechanism of action: to block action of
aldosterone• Primary use: to significantly reduce mortality
in heart failure• Adverse effects: hyperkalemia
Aldactone
Spironolactone Animation
Click here to view an animation on the topic of spironolactone.
Miscellaneous Diuretics – Carbonic Anhydrase Inhibitors
• Example: acetazolamide (Diamox)• Mechanism of action: to inhibit formation of
carbonic acid• Primary use: to decrease intraocular fluid
pressure in clients with glaucoma• Adverse effects: allergic reaction (contain
sulfa), fluid and electrolyte imbalances
Miscellaneous Diuretics – Osmotic Diuretics
• Example : mannitol• Mechanism of action: to quickly reduce
plasma volume• Primary use: to reduce intracranial pressure
due to cerebral edema• Also used to maintain urine flow in prolonged
surgery, acute renal failure, or severe renal hypoperfusion
Miscellaneous Diuretics – Osmotic Diuretics (continued)
• Adverse effects:– Headache, dizziness, tremors, dry mouth– Fluid and electrolyte imbalances,
thrombophlebitis
Drug Therapy for Renal Failure• Evaluation the patient
– Experiences a decrease in blood pressure. – Is free from, or experiences minimal adverse
effects. – Verbalizes an understanding of the drug’s use,
adverse effects and required precautions – Demonstrates proper self-administration of the
medication (e.g., dose, timing, when to notify provider).
Objective 14: list good dietary sources of potassium
• What are some good dietary sources of potassium?
• If a client is on Aldactone, what would you tell them about high potassium foods?
82
Obj. 15Nursing Implications: Diuretics
• Assessments to make
• Teaching to include:
83
Obj. 16 Drugs for UTI
• Drugs include – Antibiotics
• Fosfomycin (Monurol)• Quinolones : cinoxacin, nalidixic acid,
norfloxacin• Methenamine madelate• Nitrofurantoin
84
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
85
Quinolones
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
86
Methenamine mandelate (Mandelamine)
◦ 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
87
Nitrofurantoin (Furadantin, Macrodantin)
– 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
88
Obj. 17 Bladder Active Drugs
• Bethanecole chloride (Urecholine)• Neostigmine (Prostigmin)• Oxybutynin chloride (Ditropan)• Phenazopyridine (Pyridium)• Tolterodine (Detrol)
89
Urecholine – 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
90
Neostigmine (Prostigmin)◦ 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
91
Oxybutynin (Ditropan)• 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
92
Phenazopyridine (Pyridium)
Produces local anesthetic effect in urinary tractActs about 30 min. after administrationUsed to relieve burning, pain, urgency, frequency
in UTIReduces bladder spasms
SE to expect◦ Reddish-orange urine color
SE to report◦ Yellow sclera or skin
93
Tolterodine (Detrol)
Muscarinic receptor antagonists Inhibit muscarinic action of acetylcholine on bladder
smooth muscleUsed to treat overactive bladderDo 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
94
• Objective 18: Discuss patient education guidelines for drugs that affect the urinary system
95
• Objective 19: identify at least one nursing diagnosis that may be applicable for clients receiving diuretic therapy under the guidance of the instructor
96