Mosby's 2014 Nursing Drug Reference (118 page)

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darifenacin

(da-ree-fen′ah-sin)

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Func. class.:
Antispasmodic/Guanticholinergic

ACTION:

Bladder smooth muscle relaxation by decreasing the action of muscarinic receptors, thereby relieving overactive bladder

USES:

Urge incontinence, frequency, urgency in overactive bladder

CONTRAINDICATIONS:

Hypersensitivity, urinary retention, narrow-angle glaucoma (uncontrolled)

Precautions:
Severe hepatic disease (Child-Pugh C), GI/GU obstruction, controlled narrow-angle glaucoma, ulcerative colitis, myasthenia gravis, moderate hepatic disease (Child-Pugh B), elderly

DOSAGE AND ROUTES
Calculator


Adult: PO
7.5 mg/day, initially, may increase to 15 mg/day after 14 days if needed

Those taking a CYP3A4 inhibitor


Adult: PO
max 7.5 mg/day

Hepatic dosage


 
Adult: PO
(Child-Pugh B) max 7.5 mg/day

Available forms:
Tabs, ext rel 7.5, 15 mg

Administer:

• 
Without regard to meals, do not crush, break, chew extended-release tabs

• 
Store at room temperature

SIDE EFFECTS

CNS:
Dizziness, headache

EENT:
Blurred vision, drying eyes, sinusitis, rhinitis

GI:
Constipation, dry mouth, abdominal pain, nausea, vomiting, dyspepsia

GU:
UTI, urine retention, vaginosis

INTEG:
rash, pruritus, skin drying

MISC:
Bronchitis, flulike symptoms

PHARMACOKINETICS

Peak 7 hr, half-life 12-19 hr

INTERACTIONS

Increase:
level of—digoxin

Increase:
anticholinergic effect—anticholinergics

Increase:
darifenacin level—CYP3A4 inhibitors

Increase:
levels of—drugs metabolized by CYP2D6

NURSING CONSIDERATIONS
Assess:

• 
Urinary function: urgency, frequency, retention in bladder-outflow obstruction

• 
Constipation, may add bulk in the diet

Evaluate:

• 
Decreasing urgency, frequency of urination

Teach patient/family:

• 
To take without regard to meals; do not crush, break, chew extended-release tabs

• 
To store at room temperature

• 
To avoid breastfeeding; to notify prescriber if pregnancy (C) is planned or suspected

• 
About anticholinergic symptoms (dry mouth, constipation, dry eyes, heat prostration), not to become overheated

• 
To avoid hazardous activities until reaction is known, dizziness, blurred vision can occur

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

darunavir (Rx)

(dar-ue′na-vir)

Prezista

Func. class.:
Antiretroviral

Chem. class.:
Protease inhibitor

ACTION:

Inhibits human immunodeficiency virus (HIV-1) protease; this prevents maturation of the virus

USES:

HIV-1 in combination with ritonavir and other antiretrovirals

CONTRAINDICATIONS:

Hypersensitivity

Precautions:
Pregnancy (B), breastfeeding, children, geriatric patients, renal/hepatic disease, history of renal stones, diabetes, hypercholesterolemia, sulfonamide hypersensitivity, antimicrobial resistance, bleeding, immune reconstitution syndrome, pancreatitis

DOSAGE AND ROUTES
Calculator
Treatment-naive patients


Adult: PO
800 mg with ritonavir 100 mg daily

Treatment-experienced patients

• Adult/adolescent >40 kg/child ≥6 yr: PO
600 mg bid; with ritonavir 100 mg bid with food; 800 mg daily with ritonavir 100 mg with food (without darunavir resistance)

• Adolescent ≥30 kg, <40 kg and child ≥6 yr: PO
450 mg bid with ritonavir 60 mg bid

• Adolescent ≥20 kg, <30 kg and child ≥6 yr: PO
375 mg bid with ritonavir 50 mg bid

• Child 3 to <6 yr (14 kg to <15 kg: PO
280 mg (with ritonavir 48 mg) bid with food

• Child 3 to <6 yr (13 kg to <14 kg: PO
260 mg (with ritonavir 40 mg) bid with food

• Child 3 to <6 yr (12 kg to <13 kg: PO
240 mg (with ritonavir 40 mg) bid with food

• Child 3 to <6 yr (11 kg to <12 kg: PO
220 mg (with ritonavir 32 mg) bid with food

• Child 3 to <6 yr (10 kg to <11 kg: PO
200 mg (with ritonavir 32 mg) bid with food

Available forms:
Tabs 75, 150, 400, 600 mg

Administer:

• 
With food and ritonavir

• 
Tab should be swallowed whole

SIDE EFFECTS

CNS:
Headache, insomnia
, dizziness, somnolence

GI:
Diarrhea, abdominal pain, nausea, vomiting
, anorexia, dry mouth,
hepatitis, hepatotoxicity

GU:
Nephrolithiasis

INTEG:
Rash,
angioedema, Stevens-Johnson syndrome, toxic epidermal necrolysis, exanthematous pustulosis

MS:
Pain

OTHER:
Asthenia,
insulin-resistant hyperglycemia,
hyperlipidemia,
ketoacidosis,
lipodystrophy

PHARMACOKINETICS

95% protein binding; metabolized by CYP3A; peak 2.5-4 hr; terminal half-life 15 hr; excreted in feces 79.5%, urine 13.9%

INTERACTIONS

 
Life-threatening dysrhythmias: ergots, midazolam, rifampin, pimozide, triazolam; do not use concurrently

Increase:
myopathy, rhabdomyolysis—HMG-CoA reductase inhibitors (atorvastatin, lovastatin, simvastatin)

Increase:
darunavir levels—CYP3A4 inhibitors: (ketoconazole, itraconazole)

Increase:
levels of both products—clarithromycin, zidovudine

Increase:
levels of telapravir, rilpivarine, monitor for adverse reactions

Decrease:
darunavir levels—CYP3A4 inducers (carBAMazepine, phenytoin, fosphenytoin, PHENobarbital), rifamycins, fluconazole, nevirapine, efavirenz

Decrease:
levels of oral contraceptives

Decrease:
levels of both products—tenofovir, avoid concurrent use

Drug/Herb

Decrease:
darunavir levels—St. John’s wort; avoid concurrent use

Increase:
myopathy, rhabdomyolysis risk—red yeast rice

Drug/Food

Increase:
darunavir absorption

Drug/Lab Test

Increase:
LFTs, bilirubin, uric acid

Decrease:
WBC, neutrophils, platelets

NURSING CONSIDERATIONS
Assess:

• 
Complaints of lower back, flank pain; indicates kidney stones

• 
Signs of infection, anemia, the presence of other sexually transmitted diseases


 
Serious skin reactions:
angioedema, Stevens-Johnson syndrome, toxic epidermal necrolysis; discontinue immediately, notify prescriber


 
Hepatoxicity:
hepatic studies (ALT, AST, bilirubin, amylase); all may be elevated in those with underlying liver disease, product should be discontinued in those with increased LFTs

• 
Viral load, CD4, HIV RNA during treatment

• 
Bowel pattern before, during treatment; if severe abdominal pain with bleeding occurs, product should be discontinued; monitor hydration

• 
Hyperlipidemia:
cholesterol, triglycerides, LDL may be elevated; monitor serum cholesterol, lipid panel throughout treatment

Evaluate:

• 
Therapeutic response: decreased viral load, increased CD4 count

Teach patient/family:

• 
To use nonhormonal birth control; not to breastfeed

• 
To take as prescribed; if dose is missed, to take as soon as remembered up to 1 hr before next dose; not to double dose

• 
That product must be taken at same time of day to maintain blood levels for duration of therapy

 
That
hyperglycemia
may occur; watch for increased thirst, weight loss, hunger, dry, itchy skin; to notify prescriber if these occur

• 
To increase fluids to prevent kidney stones; if stone formation occurs, that treatment may need to be interrupted

• 
That product does not cure AIDS, only controls symptoms; not to donate blood; not to share; to notify all health care providers of use; not to use with any other products without prescriber’s approval

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