Diuretics Purpose
to decrease body fluids
Water follows sodium
Na reabsorption blocked so less H20 reabsorbed
Inc. glomerular filtration rate (GFR)
Increase Na excretion rate = inc. H20 excretion
Thiazide diuretics
Hydrochlorothiazide (HCTZ) or Chlorothiazide (Diuril)
Sulfonamide derivatives (antibiotic)
Act at Early Distal convoluted Tubule
Increase Na excretion by inhibiting Na reabsorption
Cause inc. K excretion
Lowers BP
Thiazide diuretics- chem
K wasting decrease BP mild first step in controlling high BP and HTN Early DCT loses about 10% Na here K is lost electrolyte imbalances can occur
Thiazide therapeutic use
First step agent to control HTN Edema assoc. w/ CHF Cirrhosis in liver disease Renal dysfunction Steroid or Estrogen therapy
Thiazide Adverse Reactions
Blood volume depletion Orthostatic hypotension Hypokalemia Glucose intolerance Inc. Ca, Dec. Phos. Allergic reaction (r/t sulfonamides)
Thiazide drug interactions
Resulting From altered fluid volume, low BP & electrolyte shifts Oral hypoglycemics (high BG) Corticosteroids Some Antibiotics Increased effect with antihypertensives
Thiazide Nursing Implications
Do not use if sensitive to sulfonamides Caution in Diabetics (hi BG), Gout, Give in early AM Daily Weight, BP Monitor I&O, electrolytes (esp. low K), may need supp. Assess BUN, Cr, Glu, CBC May cause photosensitivity
Thiazide Loop Diuretics
Lasix (furosemide) & bumex (Bumetanide) Derivative of Sulfonamides Highly protein-bound (99%) Works at Loop of Henle Inhibits Na & Cl reabsorption
Thiazide therapeutic use
Edema assoc. w/ CHF, Hepatic or Renal Disease
Management of HTN
Thiazide drug interaction
Aminoglycosides Oral Anticoagulants Corticosteroids r/t altered renal function, fluid & elect. imblance Affects a variety of RX
Thiazide Adverse Reactions
Severe fluid & electrolyte imbalances Hypovolemia & Dehydration Hyponatremia, Hypokalemia Postural hypotension Ototoxicity Hyperglycemia
Thiazide Nursing Implications
Assess for allergies Not if pregnant Assess I& O, Daily wt., electrolytes (Na, K, BUN, Cr, Uric acid) Check skin turgor Monitor Digoxin toxicity Monitor for inc. effect of anticoagulants Sx hearing loss, gout Encourage K rich foods or K supplement
gout
increased uric acid
Potassium Sparing Diuretics
Aldactone (spiroaldactone) & Diazide (triamterene)
Weaker diuretic
Weaker Anti HTN effect
conserves K in body
Aldactone actions
blocks aldosterone receptors in late distal tubule
Na, Cl & H20 excreted, K retained
Triamterene actions
enhances Na excretion w/ direct action on late distal tubules
Less K excreted
Potassium Sparing Therapeutic Uses
Dec. edema (CHF, cirrhosis) Reduce BP Nephrotic Syndrome Combined with K wasting diuretics Spiroaldactone + HCTZ = Aldactazide Triamterene + HCTZ = Dyazide or Maxzide
K-Sparing Drug Interactions
K wasting diuretics
Potassium supplements
High Potassium foods
K-Sparing Adverse reactions
Fluid & elec. Imbalances
Low Na & Hi K = confusion, muscle weakness,
dysrhythmmias, paralysis, diarrhea,
Fatigue, HA
Spiroladactone = enlarged breast in men & masculine effects in women
K-Sparing Nursing Implications
Monitor for electrolyte imbal (^K) renal, hepatic insufficiency Signs of hi K =confusion, muscle weakness, paralysis dysrhthmia, diarrhea Monitor I & 0, edema, Daily Wt Monitor blood count, BUN, Cr, K Warn pt of orthostatic hypotension Avoid K rich foods
Carbonic Anhydrase Inhibitors (Diamox)
Sulfonamide derivative
Action- inhibits action of carbonic anhydrase at proximal tubule
prevents formation of carbonic acid (source of H+)
Absence of H+ inhibits reabsorption of Na
In eye prevents formation of aqueous humor
Uses- glaucoma, reducing edema in:
cardiac disorders
Diamox Adverse Reactions
Fluid & elec. imbalances
Lowers K levels & bicarb levels
Allergic reactions to sulfonamides
Diamox Nursing Implications
Not to pt with allergies to sulfonamides
Not if hepatic insufficiency, pregnant
Caution in DM (^BG), low K, low Na
Caution if hi Ca or gout, taking Digoxin
Observe for sx of low K, give supplements
I & O, Daily Wt, Electrolyte levels, Blood count
Give early am, with food (dec. GI upset)
Osmotic diuretics- Mannitol Action
Action- increases osmolarity of plasma (thickens)
^GFR , decreases reabsorption of fluid & elec.
Pulls fluids from 3rd space
Mannitol use
Use - reduce intracranial pressure & cerebral edema
prevents acute renal failure
decreases pulmonary edema & intraocular pressure
aids excretion of toxic drugs
Mannitol Adverse reactions
Transient expansion of plasma volume Circulatory overload, cellular volume depletion Tachycardia, electrolyte imbalances HA, N/V Rebound of ^ ICP p Dcd
Mannitol Nursing Implications
Not if in acute renal failure, cardiac dysfunction, CHF
Not if cranial hemorrhage, severe dehydration
Monitor I & O q1h, Daily Wt, Report UO <30 ml/hr
Monitor electrolytes Na, K, Cl
VS q1h, Check IV site, Mouth Care
Monitor signs of electrolyte imbalance-thirst,
muscle cramps, weakness, paralysis
Monitor for sx CHF (^P, JVD, crackles)
Osmotic diurectics chem
60% Na lost in PCT
increase BP b/c extra fluid
taper off drug
Potassium
Body can not store K
Need to ingest daily po or IV
Needed for all nerve & muscle function & impulses
Used in K depletion
Available in several salts
KCl, K bicarb, K gluconate, K phos
No significant Rx interactions
Caution with K sparing diuretics
Adverse Reactions Hi K -listless, confusion
weakness, paralysis, EKG changes, heart block
GI irritation po, IV pain at site
MUST dilute for IV infusion
Check K levels, do not give in Renal failure
Calcium
99% in body stored in bones
If not sufficient intake will take Ca from bones
Action crucial for heart, nerve & bone function
Used in Vitamin D deficiencies, strengthens cardiac tissue
Ca poor diets, prevention of osteoporosis
pregnancy or lactation
Interacts with Digitalis =dysrhythmias, Ca Channel blockers
Adverse reactions- Hi Ca (drowsiness, muscle weakness, HA
EKG changes, kidney stones)
Nursing Implications-Inc. Vit D foods to ^ absorption (fruits, veg)
Warm IV solutions, run slow to prevent dysrhymias & arrest
Oxygenation/Circulation
Respiratory Functions Oxygenate tissues Remove CO2 Regulate acid-base Provide defense against infection
Methylxanthine Agents
relax constricted airway & reduce bronchospasm
Methylxanthines
Theophylline, Aminophylline, Theodur Originally from plants- tea, coffee, cola, chocolate elevate mood, dec. fatigue Pharmacokinetics depend on route & dose need loading dose for therapeutic level
Methylxanthines M of A
CNS stimulant decreases fatigue stimulates respiratory center (^ sensitivity to CO2) cardiovascular stimulation (^P) smooth muscle relaxation dilate coronary & pulmonary vessels
Methylxanthines Therapeutic uses
Asthma chronic bronchitis Emphysema Neonate apnea Relief of bronchospasm
Methylxanthines drug interactions
Cause toxic levels in other Rx & foods May decrease therapeutic level of other Rx Toxic Therapeutic Ineffective
Methylxanthines Adverse reactions
Transient GI irritation, N/V, HA, restless, insomnia More serious Sx of toxicity Tachycardia, palpitations, drops in BP peripheral dilation
Methylxanthines Nursing Implications
Individualize dose by serum levels Caution in pt with seizures, migraine HA Caution in cardiac disease, MI Teach pt to report side effects Avoid other stimulants- caffeine