Mosby's 2014 Nursing Drug Reference (34 page)

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amitriptyline (Rx)

(a-mee-trip′ti-leen)

Func. class.:
Antidepressant—tricyclic

Chem. class.:
Tertiary amine

Do not confuse:
amitriptyline
/nortriptyline/aminophylline

ACTION:

Blocks reuptake of norepinephrine, serotonin into nerve endings, thereby increasing action of norepinephrine, serotonin in nerve cells

USES:

Major depression

Unlabeled uses:
Neuropathic pain, prevention of cluster/migraine headaches, fibromyalgia, ADHD, bulimia nervosa, diabetic neuropathy, enuresis, insomnia, panic disorder, postherpetic neuralgia, hiccups, social phobia

CONTRAINDICATIONS:

Hypersensitivity to tricyclics, recovery phase of myocardial infarction

Precautions:
Pregnancy (C), breastfeeding, geriatric patients, seizure disorders, prostatic hypertrophy, schizophrenia, psychosis, severe depression, increased intraocular pressure, closed-angle glaucoma, urinary retention, renal/hepatic/cardiac disease, hyperthyroidism, electroshock therapy, elective surgery

 

Black Box Warning:

Children <12 yr, suicidal patients

DOSAGE AND ROUTES
Calculator
Depression

• Adult/adolescent:
PO
25-75 mg/day as single dose at bedtime or in divided doses, may increase to 200 mg/day; max 300 mg/day (if hospitalized)

• Geriatric:
PO
10-25 mg at bedtime, may be increased to 150 mg/day

Cluster/migraine headache (unlabeled)

• Adult: PO
10-300 mg/day

Pain (unlabeled)

• Adult: PO
75-300 mg/day

Fibromyalgia/insomnia (unlabeled)

• Adult: PO
10-50 mg nightly

Enuresis (unlabeled)

• Child 11-14 yr:
PO
50 mg at bedtime

• Child 6-10 yr:
PO
25 mg at bedtime

ADHD/bulimia nervosa (unlabeled)

• Adult: PO
25 mg tid, titrate to 200 mg/day by 25-50 mg at weekly intervals

• Child 6-12 yr:
PO
10-30 mg/day or 1-5 mg/kg/day in divided doses

Available forms:
Tabs 10, 25, 50, 75, 100, 150 mg

Administer:

• 
Increase fluids, bulk in diet if constipation, urinary retention occur, especially in geriatric patients

• 
With food, milk for GI symptoms

• 
Crushed if patient unable to swallow medication whole

• 
Dosage at bedtime if oversedation occurs during day; may take entire dose at bedtime; geriatric patients may not tolerate once daily dosing

SIDE EFFECTS

CNS:
Dizziness, drowsiness
, confusion, headache, anxiety, tremors, stimulation, weakness, insomnia, nightmares, EPS (geriatric patients), increased psychiatric symptoms,
seizures, suicidal thoughts

CV:
Orthostatic hypotension
,
ECG changes, tachycardia, hypertension,
palpitations,
dysrhythmias

EENT:
Blurred vision
, tinnitus, mydriasis, ophthalmoplegia

GI:
Constipation, dry mouth
, weight gain, nausea, vomiting,
paralytic ileus,
increased appetite, cramps, epigastric distress, jaundice,
hepatitis,
stomatitis

GU:
Urinary retention

HEMA:
Agranulocytosis, thrombocytopenia, eosinophilia, leukopenia, aplastic anemia

INTEG:
Rash, urticaria, sweating, pruritus, photosensitivity

PHARMACOKINETICS

Onset 45 min; peak 2-12 hr; therapeutic response 4-10 days; metabolized by liver to nortriptyline; excreted in urine, feces; crosses placenta; excreted in breast milk; half-life 10-46 hr

INTERACTIONS

 
Hyperpyretic crisis, seizures, hypertensive episode: MAOIs, do not use within 14 days of MAOIs

Increase:
risk for agranulocytosis—antithyroid agents

Increase:
QT prolongation—procainamide, quiNIDine, amiodarone, tricyclics, class IA, III antidysrhythmics

Increase:
amitriptyline levels, toxicity—cimetidine, FLUoxetine, phenothiazines, oral contraceptives, antidepressants, carBAMazepine, class IC antidysrhythmics

Increase:
effects of direct-acting sympathomimetics (EPINEPHrine), alcohol, barbiturates, benzodiazepines, CNS depressants, opioids, sedative/hypnotics

Increase:
serotonin syndrome, linezolid, methyline blue, use cautiously

Decrease:
effects of guanethidine, cloNIDine, indirect-acting sympathomimetics (ePHEDrine)

Drug/Herb

Increase:
serotonin syndrome—SAM-e, St. John’s wort, yohimbe

Increase:
CNS depression—kava, hops, chamomile, lavender, valerian

Drug/Lab Test

Increase:
serum bilirubin, blood glucose, alk phos, LFTs

Decrease:
WBCs, platelets, granulocytes

NURSING CONSIDERATIONS
Assess:

• 
B/P lying, standing; pulse q4hr; if systolic B/P drops 20 mm Hg, hold product, notify prescriber; take vital signs q4hr with CV disease; ECG for flattening of T wave, prolongation of QTc interval, bundle branch block, AV block, dysrhythmias in cardiac patients, avoid use immediately after MI

• 
Blood studies: CBC, leukocytes, differential, cardiac enzymes if patient is receiving long-term therapy

• 
Hepatic studies: AST, ALT, bilirubin

• 
Weight every wk; appetite may increase with product

• 
EPS primarily in geriatric patients: rigidity, dystonia, akathisia

 

Black Box Warning:

Mental status: mood, sensorium, affect, suicidal tendencies; increase in psychiatric symptoms: depression, panic; suicidal tendencies are higher in those ≤24 yr, restrict amount of product available

• 
Serotonin syndrome: may occur with other serotonergic products (hyperthermia, hypertension, rigidity, delirium)

• 
Urinary retention, constipation; constipation is most likely to occur in children and geriatric patients

• 
Withdrawal symptoms:
headache, nausea, vomiting, muscle pain, weakness; do not usually occur unless product was discontinued abruptly

• 
Alcohol consumption: if alcohol is consumed, hold dose until morning

• 
Pain syndromes (unlabeled):
intensity, location, severity; use pain scale; product may be taken for 1-2 mo before effective

• 
Sexual dysfunction:
erectile dysfunction, decreased libido

Perform/provide:

• 
Storage at room temp; do not freeze

Evaluate:

• 
Therapeutic response: decrease in depression, absence of suicidal thoughts

Teach patient/family:

• 
To take medication as directed; not to double dose; that therapeutic effects may take 2-3 wk; not to discontinue medication quickly after long-term use: may cause nausea, headache, malaise

• 
To use caution when driving, performing other activities that require alertness because of drowsiness, dizziness, blurred vision; to avoid rising quickly from sitting to standing (especially geriatric patients); how to manage anticholinergic effects

• 
The symptoms of serotonin syndrome

• 
To avoid alcohol, other CNS depressants

• 
To wear sunscreen or large hat when outdoors, photosensitivity occurs

• 
That contraception is recommended during treatment; to avoid breastfeeding

• 
To watch for suicide

TREATMENT OF OVERDOSE:

ECG monitoring, lavage; administer anticonvulsant, sodium bicarbonate

Canada only   Side effects:
italics
= common;
bold
= life-threatening   
Nurse Alert

amLODIPine (Rx)

(am-loe′di-peen)

Norvasc

Func. class.:
Antianginal, antihypertensive, calcium channel blocker

Chem. class.:
Dihydropyridine

Do not confuse:
amLODIPine
/aMILoride

ACTION:

Inhibits calcium ion influx across cell membrane during cardiac depolarization; produces relaxation of coronary vascular smooth muscle, peripheral vascular smooth muscle; dilates coronary vascular arteries; increases myocardial O
2
delivery in patients with vasospastic angina

USES:

Chronic stable angina pectoris, hypertension, variant angina (Prinzmetal’s angina); may coadminister with other antihypertensives, antianginals

Unlabeled uses:
Hypertension (pediatric patients)

CONTRAINDICATIONS:

Hypersensitivity to this product, severe aortic stenosis, severe obstructive CAD

 

Black Box Warning:

Hypersensitivity to dihydropyridine

Precautions:
Pregnancy (C), breastfeeding, children, geriatric patients, CHF, hypotension, hepatic injury

DOSAGE AND ROUTES
Calculator
Coronary artery disease

• Adult: PO
5-10 mg/day

• Geriatric:
PO
5 mg/day, max 10 mg/day

Hypertension

• Adult: PO
2.5-5 mg/day initially, max 10 mg/day

• Geriatric:
PO
2.5 mg/day, may increase to 5 mg/day, max 10 mg/day

• Child 6-16 yr (unlabeled):
PO
2.5-5 mg/day

• Child
<
6 yr (unlabeled):
PO
0.05-0.2 mg/kg/day in 1-2 divided doses

Hepatic dose

• Adult: PO
2.5 mg/day; may increase to 10 mg/day (antihypertensive); 5 mg/day, may increase to 10 mg/day (antianginal)

Available forms:
Tabs 2.5, 5, 10 mg

Administer:

• 
Once a day without regard to meals

SIDE EFFECTS

CNS:
Headache
, fatigue, dizziness, asthenia, anxiety, depression, insomnia, paresthesia, somnolence

CV:
Peripheral edema
, bradycardia, hypotension, palpitations, syncope, chest pain

GI:
Nausea, vomiting, diarrhea, gastric upset, constipation, flatulence, anorexia, gingival hyperplasia, dyspepsia

GU:
Nocturia, polyuria, sexual difficulties

INTEG:
Rash, pruritus, urticaria, alopecia

OTHER:
Flushing, muscle cramps, cough, weight gain, tinnitus, epistaxis

PHARMACOKINETICS

Peak 6-12 hr; half-life 30-50 hr; increased in geriatric patients, hepatic disease; metabolized by liver (CYP3A4); excreted in urine (90% as metabolites); protein binding >93%

INTERACTIONS

Increase:
neurotoxicity—lithium

Increase:
hypotension—alcohol, antihypertensives, nitrates, fentaNYL, quiNIDine

Increase:
amLODIPine level—diltiazem

Decrease:
antihypertensive effect—NSAIDs

Drug/Herb

Decrease:
effect—yohimbe

Drug/Food

Increase:
hypotensive effect—grapefruit juice

NURSING CONSIDERATIONS
Assess:

• 
Cardiac status: B/P, pulse, respirations, ECG; some patients have developed severe angina, acute MI after calcium channel blockers if obstructive CAD is severe

• 
Peripheral edema, dyspnea, jugular vein distention, crackles

• 
Angina:
intensity, location, duration of pain

Evaluate:

• 
Therapeutic response: decreased anginal pain, decreased B/P, increased exercise tolerance

Teach patient/family:

• 
To take product as prescribed, not to double or skip dose

• 
To avoid hazardous activities until stabilized on product, dizziness is no longer a problem

• 
To avoid OTC products unless directed by prescriber

• 
To comply in all areas of medical regimen: diet, exercise, stress reduction, product therapy, smoking cessation

• 
To notify prescriber of irregular heartbeat; shortness of breath; swelling of feet, face, hands; severe dizziness; constipation; nausea; hypotension; if chest pain does not improve, use nitroglycerin when angina is severe

• 
To use correct technique when monitoring pulse; to contact prescriber if pulse <50 bpm

• 
To avoid large amounts of grapefruit juice, alcohol

• 
To change positions slowly to prevent orthostatic hypotension

• 
To continue with good oral hygiene to prevent gingival disease

• 
To use sunscreen, protective clothing to prevent photosensitivity

• 
To notify all health care providers of use of this product

TREATMENT OF OVERDOSE:

Defibrillation, β-agonists, IV calcium inotropic agents, diuretics, atropine for AV block, vasopressor for hypotension

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