Cardiac Drugs Part II

Diuretic Drugs

Coagulation Modifier Drugs

Antilipemic Drugs

The Kidney

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

Classifications of Diuretics

1. Carbonic Anhydrase (Diamox): acts on the nephrons

2. Loop diuretics (Lasix): acts on the loop of Henle

3. Osmotic diuretics (Mannitol): works in the kidney on the glomerular filtration

4. Potassium sparing (Spiraldactone): works in the distal tubules

5. Thiazides (Diuril): works in distal tubules

1. 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

2

Acetazolamine

Trade name: Diamox Classification: carbonic anhyrase inhibitor Caution: check with patient regarding drug

allergy to sulfonamides or significant liver or renal dysfunction.

Dosing

Oral dosage for adults is 250 to 375 mg / day. Oral dosing for pediatric patient is 5 mg /

kg /day.

2. 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?

3. 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

4. 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.

5. 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.

Often the first drug used to lower blood pressure.

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.

Heparin

Therapeutic classification: anticoagulants Pharmacologic classification: Antithrobotic Action of heparin is to turn off the coagulation

pathway and prevent clots from forming.

Indications

Prophylaxis and treatment of various thromboembolic disorders including: Venous thromboembolism Pulmonary embolism Atrial fibrillation with embolization Acute and chronic coagulopahties Used in low doses to maintain patency of IV

catheters (heparin flush)

Contraindications

Uncontrolled bleeding Severe thrombocytopenia Open wounds Use with caution:

Severe liver or kidney disease Untreated hypertension Ulcer disease Spinal cord or brain injury

Heparin

Use with extreme caution: Severe uncontrolled hypertension Bacterial endocarditis Bleeding disorders Hemorrhagic stroke GI bleeding / ulcers Recent CNS or ophthalmologic surgery

Drugs that interact with heparin Aspirin (salycilates) NSAIDs

Dosing

IV adults: Intermittent bolus: 10,000 units followed by 5000

– 10,000 units q 4-6 hours Continuous drip: 5000 units (35-70 units / kg) SubQ: 800 to 10,000 units q 8 hours or 15,000 to

20,000 units every 12 hours IV children:

Intermittent bolus: 50 units / kg followed by 100 units / kg q 4 hours.

warfarin

Trade name: Coumadin Therapeutic classification: antigoagulants Pharmacologic classification: coumarins Action: Interferes with hepatic synthesis of

vitamin K – dependent clotting factors (II, VII, IX and X)

Used to prevent thromboembolic events

Adverse Reactions and Side Effects GI: cramps and nausea Derm: dermal necrosis Hemat: Bleeding

Dosing

PO adults: 2.5 – 10 mg / day for 2-4 days and then dose adjusted by results of prothrombin time (PT) or international normalized ration (INR).

Use lower doses in the geriatric population.

Laboratory Values

Prothrombin time (PT): measures how long it takes a clot to form in a sample of blood. PT 1.3 to 1.5

International normalization rate (INR): a standardized measure of coagulation achieved by drug therapy. INR of 2.0 to 3.0

Nursing Responsibilities

Take exactly as directed If a dose is missed take as soon possible Do not double up on doses Review food high in vitamin K Vitamin K is antidote for warfarin overdose Instruct on brushing teeth with soft brush. Report any unusual bleeding or bruising

Foods high in Vitamin K

Green leafy vegetables Prunes Noodles: spinach Pie crusts

enoxaparin

Trade name: Lovenox Therapeutic classification: anticoagulant Pharmacologic classification: antithrombotic A prototype of heparin – replacing the use of

heparin since laboratory values do not need to be monitored so tightly.

Lovenox

Action: Potentiates the inhibitory effect of antithrombin on factor Xa and thrombin.

Used to control formation of emboli production post surgery.

Dosing

DVT prophylaxis before knee / hip surgery 30 mg SC twice a day starting within 24

hours post-op and continuing for 7 – 10 days or until ambulating.

Deep Vein Thrombosis

Nursing Assessment

Assess for signs of bleeding and hemorrhage Bleeding gums Nose bleed Unusual bleeding Black tarry stools Hematuria Fall in hematocrit Bleeding from surgical site

Antiplatelet Drugs

Generic name: salicylates Trade name: Aspirin and aspirin

combinations Indication: prophylaxis of transient ischemic

attacks and myocardial infarct. Action: decreased platelet aggregation.

Antilipemic Drugs

Chapter 28

Cholesterol

A fat-soluble crystalline steroid alcohol found in animal fats and oils and egg yoke and widely distributed in the body especially in the bile, blood, brain tissue, liver kidneys, adrenal glands and myelin sheaths of nerve fibers.

Cholesterol Levels

LDL: low density cholesterol HDL: high density cholesterol (good

cholesterol)

Why is high LDL a problem?

Atherosclerotic plaque formation High correlation between Coronary Artery

Disease (CAD) and high LDL and low HDL.

Treatment Guidelines

Current guidelines recommendations: LDL levels exceeding 190 LDL levels of 160 to 190 with CAD Other risk factors

Waist circumference greater than 40 inches Serum triglycerides of 150 or greater HDL cholesterol less than 40 Blood pressure of 130/85 or higher Fasting serum glucose greater than 110

Statins

A class of cholesterol-lowering drugs that are more formally known as HMG-CoA reductase inhibitors.

First classification developed in 1987. Action: lower the blood cholesterol by

decreasing the rate of cholesterol production. Liver requires HMG-CoA reductase to

produce cholesterol.

Contraindications

Drug allergy Pregnancy Liver disease or elevation of liver enzymes.

Adverse Effects

Mild transient GI disturbances, rash and headache.

CNS: headache, dizziness, blurred vision, fatigue, nightmares, insomnia.

Severe side effect: muscle pain (myopathy) Elevation of liver enzymes: need to be

monitored about 6-8 weeks after therapy started and yearly thereafter.

atorvastatis

Lipitor Most commonly used drug to lower LDL and

raise HDL Client needs to have liver enzymes drawn

and cholesterol levels drawn 6-8 weeks after they start the drug therapy.

Call physician if muscle weakness is noted.

Niacin

Niacin or nicotinc acid is another lipid lowering drug.

Higher doses are needed than available in OTC vitamins or niacin pills.

Adverse effects: flushing, pruritus (itching) and gastrointestinal disturbances.

Life Changes

Diet: limit intake of high fat foods and animal proteins

Increase intake of omega oil contained in fish Exercise Weight control