Mosby's 2014 Nursing Drug Reference (419 page)

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

vidarabine ophthalmic
vigabatrin (Rx)

(vye-ga′ba-trin)

Sabril

Func. class.:
Anticonvulsant

Chem. class.:
GABA transaminase inhibitor

ACTION:

May inhibit reuptake and metabolism of GABA, may increase seizure threshold; structurally similar to GABA

USES:

Adjunct treatment of partial seizures in adults and children ≥12 yr, infantile spasm

CONTRAINDICATIONS:

Hypersensitivity to this product

Precautions:
Pregnancy (C), breastfeeding, children <2 yr, geriatric patients, renal/hepatic disease, suicidal thoughts/behaviors, abrupt discontinuation

 

Black Box Warning:

Visual disturbance

DOSAGE AND ROUTES
Calculator
Partial seizures

• Adult:
PO
500 mg bid, titrate in 500- mg increments at weekly intervals up to 1.5 g bid

Infantile spasm

• Infant >1 mo, child ≤2 yr:
PO
50 mg/kg/day in 2 divided doses, titrate in 25 to 50-mg/kg/day increments q3days, max 150 mg/kg/day

Renal dose

• Adult:
PO
CCr 50-80 ml/min, reduce dose by 25%; CCr 30-50 ml/min, reduce dose by 50%; CCr 10-30 ml/min, reduce dose by 75%

Available forms:
Tabs 500 mg; powder for oral solution 500 mg

Administer:
PO route (tab)

• 
Give without regard to meals

PO route (oral sol)

• 
Reconstitute immediately before using

• 
Empty contents of appropriate number of packets into clean cup

• 
For each packet, dissolve 10 ml water, conc 50 mg/ml; do not use other liquids

• 
Stir until dissolved, sol should be clear

• 
Use calibrated oral syringe to measure correct dosage

• 
Discard any unused sol

SIDE EFFECTS

CNS:
Dizziness
, irritability, lethargy,
malignant hyperthermia,
insomnia

CV:
Edema

EENT:
Visual impairment

GI:
Nausea, vomiting, diarrhea, increased appetite, abdominal pain, GI bleeding, hemorrhoids, weight gain, constipation

HEMA:
Anemia

INTEG:
Pruritus, rash

RESP:
Coughing,
respiratory depression, pulmonary embolism

PHARMACOKINETICS

Absorption >95%, no protein binding, widely distributed, not metabolized, excretion in urine 80% parent drug, excretion slowed in renal disease, peak 2 hr, half-life 7.5 hr

INTERACTIONS

Increase:
CNS depression—CNS depressants

Increase:
Serious ophthalmic effects (glaucoma, retinopathy): azaTHIOprine, chloroquine, corticosteroids, deferoxamine, ethambutol, hydroxychloroquine, interferons, loxapine, mecasermin, rh-IGF-1, pentostatin, phenothiazine, phosphodiesterase inhibitors, tamoxifen, thiothixene; avoid concurrent use

NURSING CONSIDERATIONS
Assess:

• 
Renal studies: urinalysis, BUN, urine creatinine q3mo

• 
Hepatic studies: ALT, AST, bilirubin

• 
Description of seizures: location, duration, presence of aura

• 
Mental status: mood, sensorium, affect, behavioral changes; if mental status changes, notify prescriber

Perform/provide:

• 
Storage at room temp

• 
Assistance with ambulation during early part of treatment; dizziness occurs

• 
Seizure precautions: padded side rails; move objects that may harm patient

Evaluate:

• 
Therapeutic response: decreased seizure activity; document on patient’s chart

Teach patient/family:

• 
To carry emergency ID stating patient’s name, products taken, condition, prescriber’s name and phone number

• 
To avoid driving, other activities that require alertness

• 
Not to discontinue medication quickly after long-term use

• 
To notify prescriber if pregnancy is planned or suspected

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

vilazodone (Rx)

(vil-az′oh-done)

Viibryd

Func. class.:
Antidepressant, miscellaneous

ACTION:

Novel antidepressant unrelated to other antidepressants, enhances serotonergic action by a dual mechanism

USES:

Major depression

CONTRAINDICATIONS:

Concomitant use of MOA inhibitors or within 14 days after discontinuing MOA inhibitor or within 14 days after discontinuing vilazodone

Precautions:
Pregnancy (C), labor, infants, geriatric patients, abrupt discontinuation, bipolar disorder, bleeding, operating machinery, ECT, hepatic disease, hyponatremia, hypovolemia, substance abuse, history of seizures, serotonin syndrome, neuroleptic malignant syndrome; use with serotonin precursors (e.g., tryptophan) or serotonergic drugs; suicidal ideation, worsening depression or behavior

 

Black Box Warning:

Children, suicidal ideation

DOSAGE AND ROUTES
Calculator

• Adult:
PO
10 mg × 7 days, then 20 mg × 7 days, then 40 mg/day; if taking potent CYP3A4 inhibitor, max 20 mg/day

Available forms:
Tabs 10, 20, 40 mg

Administer:

• 
With food to increase absorption

• 
Do not use within 2 wk of MAOIs

SIDE EFFECTS

CNS:
Restlessness, dizziness, drowsiness, fatigue, mania, insomnia, migraine,
neuroleptic-malignant–like syndrome,x
paresthesias,
seizures, suicidal ideation,
tremor, night sweats, dream disorders

EENT:
Cataracts, blurred vision

GI:
Nausea, vomiting, flatulence, diarrhea, xerostomia, altered taste, gastroenteritis

GU:
Decreased libido, ejaculation disorder, increased frequency of urination, sexual dysfunction

HEMA:
Bleeding, decreased platelets

MS:
Arthralgia

SYST:
Neonatal abstinence syndrome, withdrawal,
serotonin syndrome

INTERACTIONS

 
Do not use within 2 wk of MAO inhibitors

 
Increased:
serotonin syndrome—SSRIs, SNRIs, serotonin receptor agonists, selegiline, busPIRone, dextromethorphan, ergots, fenfluramine, dexfluramine, lithium, meperidine, fentaNYL, methy
lphenidate, dexmethylphenidate, metoclopramide, mirtazapine, nefazodone, pentazocine, phenothiazines, haloperidol, loxapine, thiothixene, molindone, amphetamines

Increased:
bleeding—anticoagulants, thrombolytics, platelet inhibitors, salicylates, NSAIDs

Increased:
vilazodone levels—CYP3A4 inhibitors (ketoconazole, erythromycin, efavirenz, dronedarone, clarithromycin and others)

Decrease:
vilazodone effect—CYP3A4 inducers

Drug/Food

• 
Avoid use with grapefruit juice

Drug/Herb

Increased:
serotonin syndrome—St. John’s wort

PHARMACOKINETICS

Protein binding 96%-99%, metabolized by liver by CYP3A4 (major) and CYP2C19 and CYP2D (minor) and non-CYP pathways, peak 4-5 hr, half-life 25 hr

NURSING CONSIDERATIONS
Assess:

 

Black Box Warning:

Mental status: orientation, mood behavior initially and periodically; initiate suicide precautions if indicated; history of seizures, mania

• 
Renal/hepatic status: hyponatremia

• 
Abrupt discontinuation:
Do not discontinue abruptly, taper, monitor for symptoms of withdrawal; if intolerable, resume previous dose and decrease more slowly

• 
Serotonin syndrome/neuroleptic malignant syndrome: nausea, vomiting, sedation, sweating, facial flushing, high B/P; discontinue product

Perform/provide:

• 
Storage at room temp, away from moisture, heat

Evaluate:

• 
Therapeutic response: remission of depressive symptoms

Teach patient/family:

• 
To take as directed; not to double dose

• 
To avoid abrupt discontinuation unless approved by prescriber

• 
Not to drive or operate machinery until effects are known

• 
Not to use other products unless approved by prescribed

 
To contact prescriber regarding the following: allergic reactions; personality changes (aggression, anxiety, anger, hostility); extreme sleepiness or drowsiness; feeling confused, nervous, restless or clumsy; numbness, tingling, or burning pain in hands, arms, legs, or feet; tremors; unusual behavior or thoughts about hurting oneself

• 
To notify prescriber if pregnancy is planned or suspected; avoid breastfeeding

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