Mosby's 2014 Nursing Drug Reference (191 page)

BOOK: Mosby's 2014 Nursing Drug Reference
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Canada only   Side effects:
italics
= common;
bold
= life-threatening   
Nurse Alert

gabapentin (Rx)

(gab′a-pen-tin)

Gralise, Horizant, Neurontin

Func. class.:
Anticonvulsant

Do not confuse:
Neurontin
/Noroxin/Neoral

ACTION:

Mechanism unknown; may increase seizure threshold; structurally similar to GABA; gabapentin binding sites in neocortex, hippocampus

USES:

Adjunct treatment of partial seizures, with/without generalization in patients >12 yr; adjunct for partial seizures in children 3-12 yr, postherpetic neuralgia, primary restless leg syndrome in adults

Unlabeled uses:
Tremors with multiple sclerosis (MS), neuropathic pain, bipolar disorder, migraine prophylaxis, diabetic neuropathy, nystagmus, pruritus, spasticity, menopause, hot flashes, ALS, MS

CONTRAINDICATIONS:

Hypersensitivity to this product

Precautions:
Pregnancy (C), breastfeeding, children <3 yr, geriatric patients, renal disease, hemodialysis, suicidal thoughts, depression

DOSAGE AND ROUTES
Calculator

• Adult and child >12 yr:
PO
900-1800 mg/day in 3 divided doses; may titrate by giving 300 mg on 1st day, 300 mg bid on 2nd day, 300 mg tid on 3rd day; may increase to 1800-2400 mg/day by adding 300 mg on subsequent days

• Child 3-12 yr:
PO
10-15 mg/kg/day in 3 divided doses, initially titrate dose upward over approximately 3 days; 25-35 mg/kg/day; all given in 3 divided doses

Postherpetic neuralgia

• Adult:
PO
300 mg on day 1, 600 mg/day divided bid on day 2, 900 mg/day divided tid, may titrate to 1800-3600 mg divided tid if needed;
EXT REL
(Gralise only) 300 mg on day 1, 600 mg on day 2, 900 mg on days 3-6, 1200 mg on days 7-10, 1500 mg on days 11-14, 1800 mg on day 15 and thereafter

Moderate to severe restless leg syndrome (RLS) (Horizant only)

• Adult:
PO EXT REL
600 mg daily with food at about 5
PM
; if dose missed, take next day at 5
PM

Renal dose

• Adult and child >12 yr:
CCr 30-59 ml/min, 200-700 mg bid, CCr 15-29 ml/min, 200-700 mg/day, CCr <15 ml/min, 100-300 mg/day

Uremic pruritus in hemodialysis (unlabeled)

• Adult:
PO
300 mg 3×/wk

Brachioradical pruritus (unlabeled)

• Adult:
PO
300-1800 mg/day

ALS (unlabeled)

• Adult:
PO
1000 mg/day in divided doses × 6 mo

Pendular/congenital nystagmus (unlabeled)

• Adult:
PO
900 mg/day in divided doses initially, up to 2400 mg/day in divided doses

Spasticity in MS (unlabeled)

• Adult:
PO
600-1200 mg/day in divided doses

Available forms:
Caps 100, 300, 400 mg; tabs 600, 800 mg; Horizant: ext rel tab 600 mg; oral sol 250 mg/5 ml; ext rel tab (Gralise): 300, 600 mg

Administer:

• 
Do not crush or chew caps, ext rel tabs; caps may be opened and contents put in applesauce or dissolved in juice; scored tabs may be cut in half

• 
2 hr apart when giving antacids

• 
Give without regard to meals

• 
Gradually withdraw over 7 days; abrupt withdrawal may precipitate seizures

• 
Beginning dose at bedtime to minimize daytime drowsiness

• 
Oral sol:
Measure with calibrated device

• 
Ext rel:
Give with food at about 5
PM
, bioavailability increased with food; swallow whole; do not interchange Gralise with Horizant

SIDE EFFECTS

CNS:
Drowsiness, confusion
, dizziness, fatigue, anxiety, somnolence, ataxia, amnesia, abnormal thinking, unsteady gait,
depression;
children 3-12 yr old, emotional lability, aggression, thought disorder, hyperkinesia, hostility,
seizures, suicidal ideation

CV:
Vasodilation, peripheral edema, hypotension

EENT:
Dry mouth, blurred vision,
diplopia
, nystagmus

GI:
Constipation, increased appetite, dental abnormalities, nausea, vomiting

GU:
Impotence, bleeding,
UTI

HEMA:
Leukopenia,
decreased WBC

INTEG:
Pruritus, abrasion,
Stevens-Johnson syndrome

MS:
Myalgia

RESP:
Rhinitis
, pharyngitis, cough

SYST:
Drug reaction with eosinophilia and systemic symptoms (DRESS)

PHARMACOKINETICS

Protein binding <3% not metabolized; excreted in urine (unchanged); elimination half-life 5-7 hr, prolonged to 130 hr in ESRD

INTERACTIONS

Increase:
CNS depression—alcohol, sedatives, antihistamines, all other CNS depressants

Increase:
gabapentin levels—morphine

Decrease:
gabapentin levels—antacids, sevelamar, cimetidine

Decrease:
effect of—HYDROcodone

Drug/Lab Test

False positive:
urinary protein using Ames N-multistix SG

NURSING CONSIDERATIONS
Assess:

• 
Seizures:
aura, location, duration, activity at onset


 
Pain:
location, duration, characteristics if using for chronic pain, migraine

 
Mental status: mood, sensorium, affect, behavioral changes,
suicidal thoughts/behaviors;
if mental status changes, notify prescriber

• 
Eye problems, need for ophthalmic exam before, during, after treatment (slit lamp, funduscopy, tonometry)

• 
WBC, gabapentin level (therapeutic 5.9-21 mcg/ml, toxic >85 mcg/ml)

• 
Drug reaction with eosinophilia and systemic symptoms

Perform/provide:

• 
Storage at room temp away from heat and light

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

• 
Increased fluids, bulk in diet for constipation

Evaluate:

• 
Therapeutic response: decreased seizure activity; decrease in chronic pain

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 because dizziness, drowsiness may occur

• 
Not to discontinue medication quickly after long-term use; to taper over ≥1 wk because withdrawal-precipitated seizures may occur; not to double doses if dose is missed; to take if 2 hr or more before next dose

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

• 
Not to use within 2 hr of antacid, may take regular release without regard to meals; ext rel should be taken with food; to take as directed, doses interval should not be ≥12 hr

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

galantamine (Rx)

(gah-lan′tah-meen)

Razadyne, Razadyne ER, Reminyl

Func. class.:
Anti-Alzheimer agent

Chem. class.:
Centrally acting cholinesterase inhibitor

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