Mosby's 2014 Nursing Drug Reference (141 page)

BOOK: Mosby's 2014 Nursing Drug Reference
8.46Mb size Format: txt, pdf, ePub
doxazosin (Rx)

(dox-ay′zoe-sin)

Cardura, Cardura XL

Func. class.:
Peripheral α
1
-adrenergic receptor blocker

Chem. class.:
Quinazoline

Do not confuse:
Cardura
/Coumadin/Cardene/Ridaura

ACTION:

Dilates peripheral blood vessels, lowers peripheral resistance; reduction in B/P results from peripheral α
1
-adrenergic receptors being blocked

USES:

Hypertension, urinary outflow obstruction, symptoms of benign prostatic hyperplasia

CONTRAINDICATIONS:

Hypersensitivity to quinazolines

Precautions:
Pregnancy (C), breastfeeding, children, hepatic disease

DOSAGE AND ROUTES
Calculator
BPH


Adult: PO
1 mg/day, increase in stepwise manner to 2, 4, 8 mg/day as needed at 1-2 wk intervals, max 8 mg

Hypertension


Adult: PO
1 mg/day increasing up to 16 mg/day if required; usual range 4-16 mg/day

• Geriatric: PO
0.5 mg nightly, gradually increase

Available forms:
Tabs 1, 2, 4, 8 mg; ext rel tabs 4, 8 mg

Administer:

• 
Store in tight container at room temperature

• 
Tabs
broken, crushed, or chewed; if chewed, will be bitter; do not break, crush, chew XL tabs

• 
Immediate release tab:
without regard to meals;
ext rel tabs:
give with breakfast; when switching from immediate release to ext rel, the final evening dose of immediate release should not be taken

SIDE EFFECTS

CNS:
Dizziness
, headache, drowsiness, anxiety, depression, vertigo, weakness, fatigue, asthenia

CV:
Palpitations,
orthostatic hypotension
, tachycardia, edema,
dysrhythmias,
chest pain

EENT:
Epistaxis, tinnitus, dry mouth, red sclera, pharyngitis, rhinitis

GI:
Nausea, vomiting, diarrhea, constipation, abdominal pain

GU:
Incontinence, polyuria, priapism

PHARMACOKINETICS

PO:
Onset 2 hr, peak 2-6 hr, duration 6-12 hr, half-life 22 hr, metabolized in liver, excreted via bile/feces (<63%) and in urine (9%), extensively protein bound (98%)

INTERACTIONS

Increase:
hypotensive effects—alcohol, other antihypertensives, sildenafil, vardenafil, nitrates

Decrease:
antihypertensive effects of cloNIDine

NURSING CONSIDERATIONS
Assess:

• 
Hypertension:
B/P (lying, standing), pulse 2-6 hr after each dose, with each increase; postural effects may occur, crackles, dyspnea, orthopnea with B/P; pulse; jugular venous distention during beginning treatment

• 
BPH:
urinary pattern changes (hesitancy, dribbling, incomplete bladder emptying, dysuria, urgency, nocturia, urgency incontinence, intermittency) before and during treatment

• 
I&O, weight daily; edema in feet, legs daily

Evaluate:

• 
Therapeutic response: decreased B/P; decreased symptoms of BPH

Teach patient/family:


 
That fainting occasionally occurs after 1st dose; not to drive, operate machinery for 4 hr after 1st dose, after dosage increase; to take 1st dose at bedtime; may take 1-2 wk to respond with BPH

TREATMENT OF OVERDOSE:

Administer volume expanders or vasopressors; discontinue product; place patient in supine position

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

doxepin (Rx)

(dox′e-pin)

Prudoxin Cream, Silenor, Zonalon Topical Cream

Func. class.:
Antidepressant, tricyclic, antihistamine (topical)

Chem. class.:
Dibenzoxepin, tertiary amine

ACTION:

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

USES:

Major depression, anxiety;
topical:
lichen simplex, atopic dermatitis, eczema

Unlabeled uses:
Topical pruritus, insomnia, migraine prophylaxis

CONTRAINDICATIONS:

Hypersensitivity to tricyclics, urinary retention, closed-angle glaucoma, prostatic hypertrophy, acute recovery from MI

Precautions:
Pregnancy (C) (PO) (B) (topical), breastfeeding, geriatric patients, seizures

 

Black Box Warning:

Children, suicidal patients

DOSAGE AND ROUTES
Calculator
Depression/anxiety


Adult: PO
50-75 mg/day, may increase to 300 mg/day for severely ill; give in divided doses if >150 mg/day

• Geriatric: PO
25-50 mg at bedtime, increase weekly by 25-50 mg to desired dose, max 150 mg/day

Pruritus


Adult: PO
10 mg at bedtime, may increase to 25 mg at bedtime;
TOP
apply thin film qid at least 3 hr apart

Insomnia (Silenor)


Adult: PO
6 mg 30 min before bedtime, 3 mg may be sufficient, max 6 mg/night

Available forms:
Caps 10, 25, 50, 75, 100, 150 mg; oral conc 10 mg/ml; cream 5%; tabs (Silenor) 3, 6 mg

Administer:

• 
Oral conc:
should be diluted with 120 ml water, milk or orange, grapefruit, tomato, prune, or pineapple juice; do not mix with grape juice

• 
Increased fluids, bulk in diet for constipation

• 
With food, milk for GI symptoms; do not give with carbonated beverages

• 
Dosage at bedtime to avoid oversedation during day; may take entire dose at bedtime; geriatric patients may not tolerate daily dosing

• 
Gum, hard candy, or frequent sips of water for dry mouth

• 
Topical:
by applying to affected area, rub slightly; do not use occlusive dressings

SIDE EFFECTS

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

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

EENT:
Blurred vision
, tinnitus, mydriasis, ophthalmoplegia, glossitis

GI:
Diarrhea, dry mouth
, nausea, vomiting,
paralytic ileus,
increased appetite, cramps, epigastric distress, jaundice,
hepatitis,
stomatitis, constipation

GU:
Urinary retention
,
acute renal failure

HEMA:
Agranulocytosis, thrombocytopenia, eosinophilia, leukopenia,
pancytopenia, purpuric disorder

INTEG:
Rash, urticaria, sweating, pruritus, photosensitivity

PHARMACOKINETICS

PO:
Steady state 2-8 days, metabolized by liver, excreted by kidneys, crosses placenta, excreted in breast milk, half-life 8-24 hr

INTERACTIONS

Increase:
hyperpyretic crisis, seizures, hypertensive episode—MAOIs

Increase:
hypertensive action—EPINEPHrine, norepinephrine

Increase:
hypertensive crisis—cloNIDine; do not use together

Increase:
doxepin effect—cimetidine, FLUoxetine, fluvoxaMINE, PARoxetine, sertraline

Increase:
CNS depression—barbiturates, benzodiazepines, sedative/hypnotics, alcohol, other CNS depressants

Increase:
QT interval: class IC/III antiarrhythmics (propafenone, flecainide), quinolones

Serotonin syndrome

Increase:
toxicity—SSRIs, SNRIs, serotonin-receptor agonists

Increase:
anticholinergic effects—anticholinergics

Drug/Herb

• 
Serotonin syndrome: St. John’s wort

Drug/Lab Test

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

NURSING CONSIDERATIONS
Assess:

• 
B/P (lying, standing), pulse q4hr; if systolic B/P drops 20 mm Hg, hold product, notify prescriber; VS q4hr in patients with CV disease

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

• 
Hepatic studies: AST, ALT, bilirubin

• 
Weight weekly; appetite may increase with product


 
ECG
for flattening of
T
wave, bundle branch block, AV block, dysrhythmias in cardiac patients; product should be discontinued gradually several days before surgery

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


 
Depression:
mood, sensorium, affect, suicidal tendencies, increase in psychiatric symptoms

• 
Chronic pain:
location, severity, type before and during treatment, alleviating/aggravating factors

• 
Urinary retention, constipation; constipation most likely in children, geriatric patients

• 
Withdrawal symptoms:
headache, nausea, vomiting, muscle pain, weakness; not usual unless product is discontinued abruptly

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

Perform/provide:

• 
Storage in tight container protected from direct sunlight

• 
Assistance with ambulation during beginning therapy because drowsiness/dizziness occurs; safety measures primarily for geriatric patients

• 
Check to confirm that PO medication is swallowed

Evaluate:

• 
Therapeutic response: decreased anxiety, depression

Teach patient/family:

• 
That therapeutic effect (depression) may take 2-3 wk, antianxiety effects sooner

• 
To use caution when driving, during other activities requiring alertness because of drowsiness, dizziness, blurred vision

• 
To avoid alcohol, other CNS depressants; may potentiate effects

• 
Not to discontinue medication abruptly after long-term use; may cause nausea, headache, malaise

• 
To wear sunscreen or large hat; photosensitivity occurs


 
That clinical worsening and suicide may occur

• 
To immediately report urinary retention

TREATMENT OF OVERDOSE:

ECG monitoring; lavage, activated charcoal; administer anticonvulsant, sodium bicarbonate

Other books

Extreme Difference by D. B. Reynolds-Moreton
Surrendering by Ahren Sanders
Given World by Palaia, Marian
The Dragon Variation by Sharon Lee, Steve Miller
An Inch of Ashes by David Wingrove
The Wild Belle by Lora Thomas
The Shadow of Treason by Edward Taylor
B00AFU6252 EBOK by Alba, Jessica
About Matilda by Bill Walsh