Mosby's 2014 Nursing Drug Reference (7 page)

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ANTIDYSRHYTHMICS
ACTION:

Antidysrhythmics are divided into four classes and miscellaneous antidysrhythmics:

• 
Class I increases the duration of action potential and effective refractory period and reduces disparity in the refractory period between a normal and infarcted myocardium; further subclasses include Ia, Ib, Ic

• 
Class II decreases the rate of SA node discharge, increases recovery time, slows conduction through the AV node, and decreases heart rate, which decreases O
2
consumption in the myocardium

• 
Class III increases the duration of action potential and the effective refractory period

• 
Class IV inhibits calcium ion influx across the cell membrane during cardiac depolarization; decreases SA node discharge; decreases conduction velocity through the AV node

• 
Miscellaneous antidysrhythmics include those such as adenosine, which slows conduction through the AV node, and digoxin, which decreases conduction velocity and prolongs the effective refractory period in the AV node

USES:

Antidysrhythmics are used for PVCs, tachycardia, hypertension, atrial fibrillation, angina pectoris.

CONTRAINDICATIONS:

Contraindications vary widely among products.

Precautions:
Precautions vary widely among products.

SIDE EFFECTS:

Side effects and adverse reactions vary widely among products.

PHARMACOKINETICS:

Onset, peak, and duration vary widely among products.

INTERACTIONS:

Interactions vary widely among products. Check individual monographs for specific information.

POSSIBLE NURSING DIAGNOSES:

• 
Decreased cardiac output
[uses]

• 
Diarrhea
[adverse reactions]

• 
Impaired gas exchange
[adverse reactions]

• 
Ineffective cardiac tissue perfusion
[uses]

NURSING CONSIDERATIONS
Assess:

• 
ECG continuously to determine product effectiveness, premature ventricular contractions, or other dysrhythmias

• 
IV inf rate to avoid causing nausea, vomiting

• 
For dehydration or hypovolemia

• 
B/P continuously for hypotension, hypertension

• 
I&O ratio

• 
Serum potassium

• 
Edema in feet and legs daily

Evaluate:

• 
Therapeutic response: decrease in B/P in hypertension; decreased B/P, edema, moist crackles in congestive heart failure

Teach patient/family:

• 
To comply with dosage schedule, even if patient is feeling better

• 
To report bradycardia, dizziness, confusion, depression, fever

SELECTED GENERIC NAMES
Class I

moricizine

Class Ia

disopyramide

procainamide

quiNIDine

Class II

acebutolol

esmolol

propranolol

sotalol

Class IV

verapamil

 

ANTIEMETICS
ACTION:

The antiemetics are divided into the 5-HT3 receptor antagonists, the phenothiazines, and the miscellaneous products. The 5HT3 receptor antagonists work by blocking serotonin peripherally, centrally, and in the small intestine. The phenothiazines act by blocking the chemoreceptor trigger zone in the brain. The miscellaneous products work by either decreasing motion sickness or delaying gastric emptying.

USES:

Antiemetics are used to prevent nausea and vomiting due to cancer chemotherapy, radiotherapy, and surgery (5-HT3 receptor antagonists); some of the miscellaneous products (antihistamines) work by decreasing motion sickness. Most other products are used for many types of nausea and vomiting.

CONTRAINDICATIONS:

Persons developing hypersensitive reactions should not use these products.

Precautions:
Antiemetics should be used cautiously in pregnancy, breastfeeding, hepatic disease, and some GI disorders.

Administer:

• 
Prophylactically, before nausea and vomiting occur, in cancer chemotherapy

SIDE EFFECTS:

The most common side effects are headache, dizziness, fatigue, and diarrhea.

PHARMACOKINETICS:

Onset, peak, and duration vary widely among products. Most products are metabolized by the liver and excreted by the kidneys.

INTERACTIONS:

Interactions vary widely among products. Check individual monographs for specific information. Other CNS depressants increase CNS depression.

POSSIBLE NURSING DIAGNOSES:

• 
Deficient fluid volume
[uses]

• 
Risk for injury
[uses, adverse reactions]

• 
Deficient knowledge
[teaching]

• 
Imbalanced nutrition: less than body requirements
[uses]

NURSING CONSIDERATIONS
Assess:

• 
For reason for nausea, vomiting; absence of nausea and vomiting after giving product

• 
For hypersensitivity reactions: rash, bronchospasm with some products

Perform/provide:

• 
Storage at room temperature vial/ampules, oral products

Evaluate:

• 
Therapeutic response: absence or decreasing nausea and vomiting after use

Teach patient/family:

• 
To avoid hazardous activities if dizziness occurs; ask for assistance if hospitalized

• 
To rise slowly to prevent orthostatic hypotension

• 
To teach all aspects of product usage

• 
Conservative methods to control nausea and vomiting such as sips of water or other fluids and dry crackers

 

ANTIFUNGALS (SYSTEMIC)
ACTION:

Antifungals act by increasing cell membrane permeability in susceptible organisms by binding sterols and decreasing potassium, sodium, and nutrients in the cell.

USES:

Antifungals are used for infections of histoplasmosis, blastomycosis, coccidioidomycosis, cryptococcosis, aspergillosis, phycomycosis, candidiasis, sporotrichosis causing severe meningitis, septicemia, and skin infections.

CONTRAINDICATIONS:

Persons with severe bone depression or hypersensitivity should not use these products.

Precautions:
Antifungals should be used with caution in renal/hepatic disease and pregnancy.

Administer:

• 
IV using in-line filter (mean pore diameter >1 μm) using distal veins; check for extravasation, necrosis q8hr

• 
Product only after C&S confirms organism; make sure product is used in life-threatening infections

SIDE EFFECTS:

The most serious adverse reactions include renal tubular acidosis, permanent renal impairment, anuria, oliguria, hemorrhagic gastroenteritis, acute hepatic failure, and blood dyscrasias. Some common side effects include hypokalemia, nausea, vomiting, anorexia, headache, fever, and chills.

PHARMACOKINETICS:

Onset, peak, and duration vary widely among products. Most products are metabolized in the liver and excreted in urine.

INTERACTIONS:

Interactions vary widely among products. Check individual monographs for specific information.

POSSIBLE NURSING DIAGNOSES:

• 
Risk for infection
[uses]

• 
Risk for injury
[adverse reactions]

• 
Deficient knowledge
[teaching]

NURSING CONSIDERATIONS
Assess:

• 
VS q15-30min during first infusion; note changes in pulse, B/P

• 
I&O ratio; watch for decreasing urinary output, change in specific gravity; discontinue product to prevent permanent damage to renal tubules

• 
Blood studies: CBC, K, Na, Ca, Mg q2wk

• 
Weight weekly; if weight increases over 2 lb/wk, edema is present; renal damage should be considered

• 
For renal toxicity: increasing BUN, if >40 mg/dl or if serum creatinine >3 mg/dl; product may be discontinued or dosage reduced

• 
For hepatotoxicity: increasing AST, ALT, alk phos, bilirubin

• 
For allergic reaction: dermatitis, rash; product should be discontinued, antihistamines (mild reaction) or EPINEPHrine (severe reaction) administered

• 
For hypokalemia: anorexia, drowsiness, weakness, decreased reflexes, dizziness, increased urinary output, increased thirst, paresthesias

• 
For ototoxicity: tinnitus (ringing, roaring in ears), vertigo, loss of hearing (rare)

Perform/provide:

• 
Protection from light during inf, cover with foil

• 
Symptomatic treatment as ordered for adverse reactions: aspirin, antihistamines, antiemetics, antispasmodics

• 
Storage protected from moisture and light; diluted sol is stable for 24 hr

Evaluate:

• 
Therapeutic response: decreased fever, malaise, rash, negative C&S for infecting organism

Teach patient/family:

• 
That long-term therapy may be needed to clear infection (2 wk-3 mo depending on type of infection)

 

ANTIHISTAMINES
ACTION:

Antihistamines compete with histamines for H
1
-receptor sites. They antagonize in varying degrees most of the pharmacologic effects of histamines.

USES:

Antihistamines are used to control the symptoms of allergies, rhinitis, and pruritus.

CONTRAINDICATIONS:

Hypersensitivity to H
1
-receptor antagonists occurs rarely. Patients with acute asthma and lower respiratory tract disease should not use these products since thick secretions may result. Other contraindications include closed-angle glaucoma, bladder neck obstruction, stenosing peptic ulcer, symptomatic prostatic hypertrophy, newborns, and breastfeeding.

Precautions:
Antihistamines must be used cautiously in conjunction with intraocular pressure since they increase intraocular pressure. Caution should also be used in geriatric patients, those with renal/cardiac disease, hypertension, seizure disorders, pregnancy, and those breastfeeding.

Administer:

• 
With food or milk to decrease GI symptoms; absorption may be decreased slightly

• 
Whole (sustained-release tabs)

SIDE EFFECTS:

Most products cause drowsiness; however, fexofenadine and loratadine produce little, if any, drowsiness. Other common side effects are headache and thickening of bronchial secretions. Serious blood dyscrasias may occur but are rare. Urinary retention, GI effects occur with many of these products.

PHARMACOKINETICS:

Onset varies from 20-60 min, with duration lasting 4-24 hr. In general, pharmacokinetics vary widely among products.

INTERACTIONS:

Barbiturates, opioids, hypnotics, tricyclics, or alcohol can increase CNS depression when taken with antihistamines.

POSSIBLE NURSING DIAGNOSES:

• 
Ineffective airway clearance
[uses]

NURSING CONSIDERATIONS
Assess:

• 
I&O ratio; be alert for urinary retention, frequency, dysuria; product should be discontinued if these occur

• 
CBC during long-term therapy since hemolytic anemia, although rare, may occur

• 
Blood dyscrasias: thrombocytopenia, agranulocytosis (rare)

• 
Respiratory status: rate, rhythm, increase in bronchial secretions, wheezing, chest tightness

• 
Cardiac status: palpitations, increased pulse, hypotension

Perform/provide:

• 
Hard candy, gum; frequent rinsing of mouth for dryness

Evaluate:

• 
Therapeutic response: absence of allergy symptoms, itching

Teach patient/family:

• 
To notify prescriber if confusion, sedation, hypotension occur

• 
To avoid driving, other hazardous activity if drowsiness occurs

• 
To avoid concurrent use of alcohol, other CNS depressants

• 
To discontinue a few days before skin testing

BOOK: Mosby's 2014 Nursing Drug Reference
5.15Mb size Format: txt, pdf, ePub
ads

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