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Cardiac Drugs Part II. Diuretic Drugs Coagulation Modifier Drugs Antilipemic Drugs. The Kidney . Nephron.
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Cardiac Drugs Part II Diuretic Drugs Coagulation Modifier Drugs Antilipemic Drugs
Nephron • The microscopic filtration unit of the kidney, consisting the glomerulus, proximal convoluted tubule, loop of Henle, distal convoluted tubule, collecting duct, which empties urine into the ureters.
Glomerular Filtration Rate • GFR • Is a laboratory value the serves as a gauge of how well the kidneys are functioning as filters. • 180 liters of blood filtered through kidneys per day.
Diuretic Drugs • All major classifications developed between 1950 and 1970 and are the most commonly prescribed drugs in the world.
Diuretic Drugs • Classified according to site of action
Carbonic Anhydrase Inhibitors • Action: inhibit the action of the enzyme carbonic anhydrase. • Site of action: nephrons • Indications: glaucoma, edema, epilepsy, and high altitude sickness.
Carbonic Anhyrase Inhibitors • Contraindications: • Drug allergy • Severe renal or hepatic dysfunction • Adrenal gland insufficiency
Adverse effects • Drowsiness • Anorexia • Paresthesias • Hematuria (blood in urine) • Melena (blood in stool)
Interactions • Increase in digoxin toxicity in clients taking digoxin. • Corticosteroids may cause hypokalemia. • Use with hypoglycemic drugs in diabetic type II
acetazolamine • Trade name: Diamox • Caution: check with patient regarding drug allergy to sulfonamides or significant liver or renal dysfuction.
Dosing • Oral dosage for adults is 250 to 375 mg / day. • Oral dosing for pediatric patient is 5 mg / kg /day.
Loop Diuretics • Potent diuretics • The drugs act primarily along the thick ascending limb of the loop of Henle, blocking chloride and sodium resorption. • Also activate renal prostaglandins which results in dilation of blood vessels in kidneys and lungs and rest of body.
Loop Diuretics • Used when rapid diuresis is needed. • Onset of action is1 hour and duration is 1-2 hours. • Usually given in a single daily dose
Major Side Effect • Electrolyte imbalance • Especially sodium and potassium • Nurse alert: always check serum potassium and sodium levels before administering.
Good Effects of Loop Diuretics • Reduces blood pressure • Reduces pulmonary vascular resistance • Reduces systemic vascular resistance • Reduces central venous pressure • Reduces left ventricular end-diastolic pressure.
Contraindications • Drug allergy • Allergy to sulfonamides
furosemide • Trade name: Lasix • Therapeutic classification: diuretic • Pharmacologic classification: loop diuretic • Primary use: pulmonary edema and edema associated with heart failure, liver disease and nephrotic syndrome. • Used in treatment of hypertension caused by heart failure.
Lasix Dosing • Adult: IV 0.5 to 1 mg / kg / dose (maximum 200 mg / day.
Drug calculation problem • Client weighs 170 pounds • Convert pounds to kilograms _________ • Safe range of drug _______ to _______ • Physician order: 56 mg of Lasix IV STAT
Drug calculation problem • Lasix is provided as 10 mg / mL • How much would you need to draw up to give the 56 mg?
Osmotic Diuretics • Action: increases the osmotic pressure of the glomerular filtrate inhibiting the reabsorption of water and electrolytes.
When Used? • Oliguric phase of acute renal failure. • Increased intracranial or intraocular pressure.
mannitol • Trade name: Osmitrol, Resectisol • Therapeutic classification: diuretic • Pharmacologic classification: osmotic diuretic
mannitol adverse effects • CNS: confusion and headaches • EENT: blurred vision • Cardiovascular: transient fluid expansion, chest pain, CHF, pulmonary edema, tachycardia • GI: Nausea, vomiting and thirst • GU: urinary retention
Dosing • Adult dosing: 500 mg / kg (Given in intravenous solution) • Onset 30 to 60 minutes • Peak 1 hour • Duration 6-8 hours
Nursing Assessment • Monitor vital signs • Urine output • Signs and symptoms of dehydration • Decreased skin turgor • Fever • Dry skin and mucous membranes • Low urine output
Potassium Sparing Diuretics • Also called aldosterone-inhibiting diuretics because they block the aldosterone receptors. • This causes sodium and water to be excreted and potassium to be retained.
Potassium Sparing Diuretics • Action: drugs work in the collecting ducts and distal convoluted tubules, where they interfere with sodium-potassium exchange.
Indications • Used with other agents to treat edema or hypertension
Contraindications and Precautions • Use with caution in geriatric or debilitated patients or patients with diabetes mellitus (increased risk of hyperkalemia). • Renal insufficiency (BUN >30 • History of gout or kidney stones
Adverse Reactions / Side Effects • CNS: dizziness, clumsiness, headache • Gastrointestinal: cramps, nausea, vomiting, diarrhea • Other: urinary frequency, weakness, hyperkalemia.
spironolactone • Trade name: Aldactone • Therapeutic classification: diuretic • Pharmacological classification: potassium-sparing diuretic
Aldactone • Onset: unknown • Peak: 2-3 days • Duration: 2-3 days
Dosing • PO Adults • 25-400 mg per day as a single dose or 2-4 divided doses. • PO Children • 1-3 mg / kg / day. Daily or 2-4 divided doses.
Thiazides and Thiazide-Like Diuretics • Action: increases excretion of sodium and water by inhibiting sodium reabsorption in the distal tubule. • Therapeutic effects: Lowering of blood pressure in hypertensive patients and diuresis with mobilization of edema.
Contraindications • Allergy to sulfonamides • Used cautiously in clients with renal or severe hepatic impairment.
Adverse Reactions and Side Effects • CNS: dizziness, drowsiness, lethargy and weakness • CV: hypotension • GI: anorexia, cramps, hepatitis, • Dermatology: photosensitivity, rashes • Fluid / electrolytes: Hypokalemia, dehydration, hyponatremia • MS: muscle cramps
hydrochlorothiazide • Trade name: Esidrix, HydroDIURIL • Therapeutic classification: antihypertensive, diuretic • Indication: • management of mild to moderate hypertension • Treatment of edema associated with CHF, renal dysfunction, cirrhosis, corticosteroid therapy, hormonal therapy
Dosing • PO adults: 250 mg – 1 gram / day as a single dose or in divided doses • PO children > 6 months: 10-20 mg/kg/day as a single dose or in divided doses.
HydroDIURIL • Onset 2 hours • Peak 3-6 hours • Duration 6-12 hours
Laboratory Considerations • Electrolytes especially potassium • Blood glucose • BUN • Serum Creatinine • Uric acid
Coagulation Modifier Drugs Chapter 27
Anticoagulant • A substances that prevents or delays coagulations of the blood.
Antiplatelet Drugs • A substance that prevents platelet plugs from forming, which may be beneficial in defending the body against heart attacks and strokes.
Anticoagulants • Prevent the formation of a clot by inhibiting certain clotting factors called anticoagulants. • Only given prophylactically because they have no direct effect on a clot that has already formed.
Clots / Embolus • Clot: Insoluble solid elements of blood that have chemically separated from the liquid of plasma component of the blood. • Embolus: a blood clot that has been dislodged from the wall of a blood vessel and is traveling throughout the bloodstream.
Anticoagulants • Also called antithrombotic drugs because they all work to prevent the formation of clots or thrombus.
Embolus • Stoke or cerebral vascular accident occurs when a blood clot travels to the brain. • Pulmonary embolism occurs when a blood clot travels to the lungs. • Deep vein thrombosis or DVT: clot in the veins of the legs.
Anticoagulants • All anticoagulants work in the clotting cascade, but do so at different points.