Mosby's 2014 Nursing Drug Reference (7 page)
Read Mosby's 2014 Nursing Drug Reference Online
Authors: Linda Skidmore-Roth
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
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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
Antidysrhythmics are used for PVCs, tachycardia, hypertension, atrial fibrillation, angina pectoris.
Contraindications vary widely among products.
Precautions:
Precautions vary widely among products.
Side effects and adverse reactions vary widely among products.
Onset, peak, and duration vary widely among products.
Interactions vary widely among products. Check individual monographs for specific information.
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Decreased cardiac output
[uses]
•
Diarrhea
[adverse reactions]
•
Impaired gas exchange
[adverse reactions]
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Ineffective cardiac tissue perfusion
[uses]
•
ECG continuously to determine product effectiveness, premature ventricular contractions, or other dysrhythmias
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IV inf rate to avoid causing nausea, vomiting
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For dehydration or hypovolemia
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B/P continuously for hypotension, hypertension
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I&O ratio
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Serum potassium
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Edema in feet and legs daily
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Therapeutic response: decrease in B/P in hypertension; decreased B/P, edema, moist crackles in congestive heart failure
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To comply with dosage schedule, even if patient is feeling better
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To report bradycardia, dizziness, confusion, depression, fever
moricizine
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.
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.
Persons developing hypersensitive reactions should not use these products.
Precautions:
Antiemetics should be used cautiously in pregnancy, breastfeeding, hepatic disease, and some GI disorders.
•
Prophylactically, before nausea and vomiting occur, in cancer chemotherapy
The most common side effects are headache, dizziness, fatigue, and diarrhea.
Onset, peak, and duration vary widely among products. Most products are metabolized by the liver and excreted by the kidneys.
Interactions vary widely among products. Check individual monographs for specific information. Other CNS depressants increase CNS depression.
•
Deficient fluid volume
[uses]
•
Risk for injury
[uses, adverse reactions]
•
Deficient knowledge
[teaching]
•
Imbalanced nutrition: less than body requirements
[uses]
•
For reason for nausea, vomiting; absence of nausea and vomiting after giving product
•
For hypersensitivity reactions: rash, bronchospasm with some products
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Storage at room temperature vial/ampules, oral products
•
Therapeutic response: absence or decreasing nausea and vomiting after use
•
To avoid hazardous activities if dizziness occurs; ask for assistance if hospitalized
•
To rise slowly to prevent orthostatic hypotension
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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 act by increasing cell membrane permeability in susceptible organisms by binding sterols and decreasing potassium, sodium, and nutrients in the cell.
Antifungals are used for infections of histoplasmosis, blastomycosis, coccidioidomycosis, cryptococcosis, aspergillosis, phycomycosis, candidiasis, sporotrichosis causing severe meningitis, septicemia, and skin infections.
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.
•
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
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.
Onset, peak, and duration vary widely among products. Most products are metabolized in the liver and excreted in urine.
Interactions vary widely among products. Check individual monographs for specific information.
•
Risk for infection
[uses]
•
Risk for injury
[adverse reactions]
•
Deficient knowledge
[teaching]
•
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)
•
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
•
Therapeutic response: decreased fever, malaise, rash, negative C&S for infecting organism
•
That long-term therapy may be needed to clear infection (2 wk-3 mo depending on type of infection)
Antihistamines compete with histamines for H
1
-receptor sites. They antagonize in varying degrees most of the pharmacologic effects of histamines.
Antihistamines are used to control the symptoms of allergies, rhinitis, and pruritus.
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.
•
With food or milk to decrease GI symptoms; absorption may be decreased slightly
•
Whole (sustained-release tabs)
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.
Onset varies from 20-60 min, with duration lasting 4-24 hr. In general, pharmacokinetics vary widely among products.
Barbiturates, opioids, hypnotics, tricyclics, or alcohol can increase CNS depression when taken with antihistamines.
•
Ineffective airway clearance
[uses]
•
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
•
Hard candy, gum; frequent rinsing of mouth for dryness
•
Therapeutic response: absence of allergy symptoms, itching
•
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
brompheniramine
cyproheptadine