Mosby's 2014 Nursing Drug Reference (30 page)

BOOK: Mosby's 2014 Nursing Drug Reference
6.59Mb size Format: txt, pdf, ePub
amantadine (Rx)

(a-man′ta-deen)

Func. class.:
Antiviral, antiparkinsonian agent

Chem. class.:
Tricyclic amine

Do not confuse:
amantadine
/ranitidine/rimantidine

ACTION:

Prevents uncoating of nucleic acid in viral cell, thereby preventing penetration of virus to host; causes release of DOPamine from neurons

USES:

Prophylaxis or treatment of influenza type A, EPS, parkinsonism, Parkinson’s disease

Unlabeled uses:
Neuroleptic malignant syndrome, MS-associated fatigue

CONTRAINDICATIONS:

Hypersensitivity, breastfeeding, children <1 eczematic rash

Precautions:
Pregnancy (C), geriatric patients, epilepsy, CHF, orthostatic hypotension, psychiatric disorders, renal/hepatic disease, peripheral edema

DOSAGE AND ROUTES
Calculator
Influenza type A

• Adult and child >9 yr:
PO
200 mg/day in single dose or divided bid

• Geriatric:
PO
No more than 100 mg/day

• Child 1-8 yr:
PO
4.4-8.8 mg/kg/day divided bid-tid, max 150 mg/day

Extrapyramidal reaction/parkinsonism

• Adult: PO
100 mg bid up to 400 mg/day in EPS; give for 1 wk then 100 mg as needed up to 400 mg for parkinsonism

Renal dose

• Adult: PO
CCr 30-50 ml/min 200 mg 1st day then 100 mg/day; CCr 15-29 ml/min 100 mg 1st day then 100 mg on alternate days; CCr 15 ml/min reduce dose and interval to 200 mg q7days

MS-associated fatigue (unlabeled)

• Adult: PO
200 mg/day or 100 mg bid

Neuroleptic malignant syndrome (unlabeled)

• Adult: PO
100 mg bid × 3 wk

Available forms:
Caps 100 mg; oral sol 50 mg/5 ml; tab 100 mg

Administer:

• 
Prophylaxis:
before exposure to influenza; continue for 10 days after contact;
treatment:
initiate within 24-48 hr of onset of symptoms, continue for 24-48 hr after symptoms disappear

• 
After meals for better absorption to decrease GI symptoms; at least 4 hr before bedtime to prevent insomnia

• 
In divided doses to prevent CNS disturbances: headache, dizziness, fatigue, drowsiness

SIDE EFFECTS

CNS:
Headache, dizziness
, drowsiness, fatigue,
anxiety
, psychosis,
depression, hallucinations
, tremors,
seizures,
confusion,
insomnia

CV:
Orthostatic hypotension
,
CHF

EENT:
Blurred vision

GI:
Nausea, vomiting
, constipation, dry mouth, anorexia

GU:
Frequency, retention

HEMA:
Leukopenia, agranulocytosis

INTEG:
Photosensitivity, dermatitis, livedo reticularis

PHARMACOKINETICS

PO:
Onset 48 hr, peak 1-4 hr, half-life 24 hr, not metabolized, excreted in urine (90%) unchanged, crosses placenta, excreted in breast milk

INTERACTIONS

Increase:
anticholinergic response—atropine, other anticholinergics

Increase:
CNS stimulation—CNS stimulants

Decrease:
amantadine effect—metoclopramide, phenothiazines

Decrease:
renal excretion of amantadine—triamterene, hydrochlorothiazide

Decrease:
effect—S/B H1N1 influenza A virus vaccine; avoid use 2 wk before or 48 hr after amantadine

Drug/Lab Test

Increase:
BUN, creatinine, alk phos, CK, LDH, bilirubin, AST, ALT, GGT

NURSING CONSIDERATIONS
Assess:

• 
Mental status: may cause increased psychiatric disorders especially in the elderly

• 
CHF
(weight gain, jugular venous distention, dyspnea, crackles)

• 
Skin eruptions, photosensitivity after administration of product

• 
Reaction to each medication

• 
Signs of infection

• 
Livedo reticularis:
mottling of the skin, usually red; edema; itching in lower extremities

• 
Parkinson’s disease:
gait, tremors, akinesia, rigidity, may be effective if anticholinergics have not been effective

 
Toxicity:
confusion, behavioral changes, hypotension, seizures

Perform/provide:

• 
Storage in tight, dry container

Evaluate:

• 
Therapeutic response: absence of fever, malaise, cough, dyspnea with infection; tremors, shuffling gait with Parkinson’s disease

Teach patient/family:

• 
To change body position slowly to prevent orthostatic hypotension

• 
About aspects of product therapy: to report dyspnea, weight gain, dizziness, poor concentration, dysuria, complex sleep behaviors

• 
To avoid hazardous activities if dizziness, blurred vision occurs

• 
To take product exactly as prescribed; parkinsonian crisis may occur if product is discontinued abruptly; not to double dose; if a dose is missed, not to take within 4 hr of next dose; caps may be opened and mixed with food

• 
To avoid alcohol

TREATMENT OF OVERDOSE:

Withdraw product, maintain airway, administer EPINEPHrine, aminophylline, O
2
, IV corticosteroids, physostigmine

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

ambrisentan (Rx)

(am-bri-sen′tan)

Letairis

Func. class.:
Antihypertensive

Chem class.:
Vasodilator/endothelin receptor antagonist

ACTION:

Endothelin-A receptor antagonist; endothelin-A is vasoconstrictor

USES:

Pulmonary arterial hypertension, alone or in combination with other antihypertensives

CONTRAINDICATIONS:

Breastfeeding, hypersensitivity, idiopathic pulmonary fibrosis (IPF)

 

Black Box Warning:

Pregnancy (X)

Precautions:
Children, females, geriatric patients, hepatitis, anemia, heart failure, jaundice, peripheral edema, hepatic disease

DOSAGE AND ROUTES
Calculator

• Adult: PO
5 mg/day; may increase to 10 mg/day if needed

Hepatic dose

• Adult: PO
Discontinue if AST/ALT >5× ULN, or if elevations are accompanied by bilirubin >2× ULN, or other signs of liver dysfunction

Available forms:
Tabs 5, 10 mg

Administer:

• 
Do not break, crush, chew tabs

• 
Daily with a full glass of water without regard to food

• 
Do not discontinue abruptly

• 
Only those facilities enrolled in the LEAP program (866-664-5327) may administer this product

SIDE EFFECTS

CNS:
Headache
, fever, flushing, fatigue

CV:
Orthostatic hypotension, hypotension,
peripheral edema
, palpitations

EENT:
Sinusitis, rhinitis

GI:
Abdominal pain, constipation, anorexia,
hepatotoxicity

GU:
Decreased sperm counts

HEMA:
Anemia

INTEG:
Rash,
angioedema

RESP:
Pharyngitis, dyspnea,
pulmonary edema, veno-occlusive disease (VOD)

PHARMACOKINETICS

Rapidly absorbed, peak 2 hr, protein binding 99%, metabolized by CYP3A4, CYP2C19, terminal half-life 15 hr, effective half-life 9 hr

INTERACTIONS

• 
Possibly increase ambrisentan: cimetidine, clopidogrel, efavirenz, felbamate, fluoxetine, modafinil, oxcarbazepine, ticlopidine

Increase:
hypotension—other antihypertensives, diuretics, MAOIs

Increase:
ambrisentan—CYP3A4 inhibitors (amprenavir, aprepitant, atazanavir, clarithromycin, conivaptan, cycloSPORINE, dalfopristin, danazol, darunavir, erythromycin, estradiol, imatinib, itraconazole, ketoconazole, nefazodone, nelfinavir, propoxyphene, quinupristin, ritonavir, RU-486, saquinavir, tamoxifen, telithromycin, troleandomycin, zafirlukast); CYP2C19/CYP3A4 (chloramphenicol, delavirdine, fluconazole, fluvoxaMINE, isoniazid, voriconazole)

Decrease:
ambrisentan—CYP3A4 inducers (carBAMazepine, PHENobarbital, phenytoin, rifampin)

Decrease:
ambrisentan absorption—mefloquine, niCARdipine, propafenone, quiNIDine, ranolazine, tacrolimus, testosterone

Drug/Herb

• 
Need for ambrisentan dosage change: St. John’s wort, ephedra (ma huang)

Drug/Food

• 
Avoid use with grapefruit products

Drug/Lab Test

Increase:
LFTs, bilirubin

Decrease:
Hct, Hgb

NURSING CONSIDERATIONS
Assess:

• 
Pulmonary status:
improvement in breathing, ability to exercise; pulmonary edema that may indicate veno-occlusive disease

• 
Blood studies: CBC with differential; Hct, Hgb may be decreased

• 
Liver function tests: AST, ALT, bilirubin

 

Black Box Warning:

Assess pregnancy status before giving this product; pregnancy category X

• 
Hepatotoxicity: nausea, vomiting, abdominal pain/cramping, jaundice, anorexia, itching

Perform/provide:

• 
Storage in tight container at room temp

Evaluate:

• 
Therapeutic response: decrease in B/P; decreased shortness of breath

Teach patient/family:

• 
The importance of complying with dosage schedule even if feeling better

 

Black Box Warning:

To notify if pregnancy is planned or suspected (if pregnant, product will need to be discontinued, pregnancy test done monthly); to use 2 contraception methods while taking this product

• 
Not to use OTC products including herbs, supplements unless approved by prescriber

• 
To report to prescriber immediately: dizziness, faintness, chest pain, palpitations, uneven or rapid heart rate, headache, edema, weight gain

• 
To report hepatic dysfunction: nausea/vomiting, anorexia, fatigue, jaundice, right upper quadrant abdominal pain, itching, fever, malaise

Other books

The Rags of Time by Maureen Howard
Tell No Lies by Gregg Hurwitz
Carla Kelly by Borrowed Light
Coming Home by Karen Kingsbury
Caitlin by Jade Parker
The Eye of God by James Rollins
Back Blast by Mark Greaney
Hetty by Charles Slack
Common Ground by Rob Cowen