Mosby's 2014 Nursing Drug Reference (272 page)

minoxidil (Rx,
OTC
)

(mi-nox′i-dill)

Loniten, Rogaine (topical)

Func. class.:
Antihypertensive

Chem. class.:
Vasodilator, peripheral

Do not confuse:
minoxidil
/Monopril
Loniten
/Lipitor

ACTION:

Directly relaxes arteriolar smooth muscle, causing vasodilation; reduces peripheral vascular resistance, decreases B/P

USES:

Severe hypertension unresponsive to other therapy (use with diuretic and β-blocker); topically to treat alopecia

Unlabeled uses:
Scleroderma renal crisis (SRC) to control hypertension

CONTRAINDICATIONS:

Dissecting aortic aneurysm, hypersensitivity, pheochromocytoma

 

Black Box Warning:

Acute MI

Precautions:
Pregnancy (C), breastfeeding, children, geriatric patients, renal disease, CVD

 

Black Box Warning:

CAD, CHF, cardiac disease, cardiac tamponade, edema, hypotension, orthostatic hypotension, pericardial effusion

DOSAGE AND ROUTES
Calculator
Severe hypertension

• Adult:
PO
2.5-5 mg/day in 1-2 divided doses; max 100 mg/day; usual range 10-40 mg/day in single dose

• Geriatric:
PO
2.5 mg/day, may be increased gradually

• Child <12 yr:
PO
(initial) 0.1-0.2 mg/kg/day; (effective range) 0.25-1 mg/kg/day; (max) 50 mg/day

Alopecia

• Adult:
TOP
1 ml bid, rub into scalp daily, max 2 ml/day

Scleroderma renal crisis (unlabeled)

• Adult:
PO
5 mg/day in 1-2 divided doses, increase after 3 days by 10-20 mg/day to reach desired B/P, max 100 mg/day

Available forms:
Tabs 2.5, 10 mg; topical 2%, 5% sol; topical foam 5%

Administer:
PO route

• 
With meals for better absorption, to decrease GI symptoms

• 
With β-blocker and/or diuretic for hypertension

Topical route

• 
1 ml no matter how much balding has occurred; increasing dosage does not speed growth

SIDE EFFECTS
Systemic

CNS:
Headache, fatigue

CV:
Severe rebound hypertension on withdrawal in children
, tachycardia, angina, increased T wave,
CHF, pulmonary edema, pericardial effusion,
edema, sodium, water retention, hypotension

GI:
Nausea, vomiting

GU:
Breast tenderness

HEMA:
Hct, Hgb; erythrocyte count may decrease initially

INTEG:
Pruritus,
Stevens-Johnson syndrome,
rash, hirsutism

PHARMACOKINETICS

PO:
Onset 30 min, peak 2-3 hr, duration 48-120 hr; half-life 4.2 hr; metabolized in liver; metabolites excreted in urine, feces; protein binding minimal

INTERACTIONS

Increase:
hypotension—antihypertensives, MAOIs

Decrease:
antihypertensive effect—NSAIDs, salicylates, estrogens

Drug/Herb

Increase:
antihypertensive effect—hawthorn

Drug/Lab Test

Increase:
renal studies

Decrease:
Hgb/Hct/RBC

NURSING CONSIDERATIONS
Assess:

 
Monitor closely; usually given with β-blocker to prevent tachycardia and increased myocardial workload; usually given with diuretic to prevent serious fluid accumulation; patient should be hospitalized during beginning treatment

• 
Nausea, edema in feet, legs daily

• 
Skin turgor, dryness of mucous membranes for hydration status

• 
Crackles, dyspnea, orthopnea

• 
Electrolytes: potassium, sodium, chloride, CO
2

• 
Renal studies: catecholamines, BUN, creatinine

• 
Hepatic studies: AST, ALT, alk phos

• 
B/P, pulse

• 
Weight daily, I&O

Perform/provide:

• 
Storage protected from light and heat

Evaluate:

• 
Therapeutic response: decreased B/P, increased hair growth

Teach patient/family:

• 
That body hair will increase but is reversible after discontinuing treatment

• 
Not to discontinue product abruptly

• 
To report pitting edema, dizziness, weight gain >5 lb, SOB, bruising or bleeding, heart rate >20 beats/min over normal, severe indigestion, dizziness, lightheadedness, panting, new or aggravated symptoms of angina

• 
To take product exactly as prescribed because serious side effects may occur

Topical

• 
That for topical use, treatment must continue for the long term, or new hair will be lost

• 
Not to use except on scalp

TREATMENT OF OVERDOSE:

Administer normal saline IV, vasopressors

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

mirtazapine (Rx)

(mer-ta′za-peen)

Remeron, Remeron Soltab

Func. class.:
Antidepressant

Chem. class.:
Tetracyclic

ACTION:

Blocks reuptake of norepinephrine and serotonin into nerve endings, thereby increasing action of norepinephrine and serotonin in nerve cells; antagonist of central α
2
-receptors; blocks histamine receptors

USES:

Depression; dysthymic disorder; bipolar disorder: depressed, agitated depression

Unlabeled uses:
Resting tremor, benign familial tremor, levodopa-induced dyskinesias, pruritus

CONTRAINDICATIONS:

Hypersensitivity to tricyclics, recovery phase of MI, agranulocytosis, jaundice

Precautions:
Pregnancy (C), geriatric patients, suicidal patients, severe depression, increased intraocular pressure, closed-angle glaucoma, urinary retention, cardiac/renal/hepatic disease, hypo/hyperthyroidism, electroshock therapy, elective surgery, seizure disorder, bone marrow suppression, thrombocytopenia

 

Black Box Warning:

Suicidal ideation, children

DOSAGE AND ROUTES
Calculator

• Adult:
PO
15 mg/day at bedtime, maintenance to continue for 6 mo, titrate up to 45 mg/day;
ORALLY DISINTEGRATING
tabs: open blister pack, place tab on tongue, allow to disintegrate, swallow

• Geriatric:
PO
7.5 mg at bedtime, increase by 7.5 mg q1-2wk to desired dose, max 45 mg/day

Resting tremor/benign familial tremor/levodopa-induced dyskinesias (unlabeled)

• Adult:
PO
titrate up to 30 mg at bedtime

Pruritus (unlabeled)

• Adult:
PO
15-30 mg/day

Available forms:
Tabs 7.5, 15, 30, 45 mg; orally disintegrating tab (Soltab) 15, 30, 45 mg

Administer:

• 
Increased fluids, bulk in diet for constipation, especially for geriatric patients

• 
With food, milk for GI symptoms

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

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

• 
Orally disintegrating tab:
no water needed; allow to dissolve on tongue, do not split

SIDE EFFECTS

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

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

EENT:
Blurred vision
, tinnitus, mydriasis

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

GU:
Urinary retention
,
acute renal failure

HEMA:
Agranulocytosis, thrombocytopenia, eosinophilia, leukopenia

INTEG:
Rash, urticaria, sweating, pruritus, photosensitivity

SYST:
Flulike symptoms, increased cholesterol levels

PHARMACOKINETICS

PO:
Peak 2 hr, metabolized by CYP1A2, 2D6, 3A4 in liver; excreted in urine, feces; crosses placenta; half-life 20-40 hr, protein binding 85%

INTERACTIONS

 
Increase: hyperpyretic crisis, seizures, hypertensive episode—MAOIs

Increase:
CNS depression—alcohol, barbiturates, benzodiazepines, other CNS depressants

Increase:
serotonin syndrome—SSRIs, SNRIs, serotonin-receptor agonists, fenfluramine, dexfenfluramine, sibutramine, nefazodone

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

Drug/Herb

• 
Serotonin syndrome: St. John’s wort

Increase:
CNS depression—kava

Drug/Lab Test

Increase:
serum bilirubin, blood glucose, alk phos

Decrease:
VMA, 5-HIAA

False increase:
urinary catecholamines

NURSING CONSIDERATIONS
Assess:

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

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

• 
Hepatic studies: AST, ALT, bilirubin, creatinine

• 
Weight weekly; appetite may increase with product

• 
ECG for flattening of T wave, bundle branch block, AV block, dysrhythmias in cardiac patients

 

Black Box Warning:

Mental status: mood, sensorium, affect, suicidal tendencies (especially among adolescents, young adults), increase in psychiatric symptoms: depression, panic; EPS primarily in geriatric patients: rigidity, dystonia, akathisia

 
Serotonin syndrome:
hyperthermia, hypertension, myoclonus, rigidity, delirium, coma; if using other serotonergic products

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

Perform/provide:

• 
Storage in tight container at room temp; do not freeze

• 
Assistance with ambulation during beginning therapy, since drowsiness, dizziness occurs

Evaluate:

• 
Therapeutic response: decreased depression

Teach patient/family:

• 
That therapeutic effects may take 2-3 wk; to take at bedtime; that there is decreased sedation with increased doses

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

• 
To avoid alcohol, other CNS depressants

• 
About how to take orally disintegrating tabs; dissolve on tongue, swallow

• 
Not to use within 14 days of MAOIs

 

Black Box Warning:

To notify prescriber of suicidal thoughts, behavior

TREATMENT OF OVERDOSE:

ECG monitoring, lavage, activated charcoal; administer anticonvulsant, IV fluids

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