Mosby's 2014 Nursing Drug Reference (137 page)

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

docosanol topical

See
Appendix B

 

docusate calcium (
OTC
)

(dok′yoo-sate cal′see-um)

Kao-Tin, Stool Softener DC, Sur-Q-Lax, Walgreen’s Stool Softener

docusate sodium (
OTC
)

Colace, Correctol, Diocto, Doc-Q-Lace, Docu DOK, Doculace, Enemeez, Equaline Stool Softener, Good Sense Stool Softener, Leader Stool Softener, Phillip’s Stool Softener, Regulex
, Select Brand Docusate Sodium, Selex
, Silace, Soflax
, Top Care Stool Softener, Walgreen’s Stool Softener

Func. class.:
Laxative, emollient; stool softener

Chem. class.:
Anionic surfactant

ACTION:

Increases water, fat penetration in intestine; allows for easier passage of stool

USES:

Prevention of dry, hard stools

CONTRAINDICATIONS:

Hypersensitivity, obstruction, fecal impaction, nausea/vomiting

Precautions:
Pregnancy (C), breastfeeding

DOSAGE AND ROUTES
Calculator


Adult: PO
50-300 mg/day (sodium) or 240 mg (calcium) prn;
ENEMA
4 ml

• Child >12 yr: ENEMA
2 ml

• Child 6-12 yr: PO
40-150 mg/day (sodium) in divided doses

• Child 3-6 yr: PO
20-60 mg/day (sodium) in divided doses

• Child <3 yr: PO
10-40 mg/day (sodium) in divided doses

Available forms:
Calcium:
240 mg;
sodium:
caps 50, 100, 250 mg; tabs 100 mg; syr 20 mg/5 ml, 50 mg/15 ml, 100
mg/30 ml, 150 mg/15 ml; oral sol 10, 50 mg/ml; enema 283 mg/3.9 cap

Administer:

• 
Swallow tabs whole; do not break, crush, or chew

• 
Oral sol: diluted in milk, fruit juice to decrease bitter taste

• 
In morning or evening (oral dose)

SIDE EFFECTS

EENT:
Bitter taste, throat irritation

GI:
Nausea, anorexia, cramps, diarrhea

INTEG:
Rash

PHARMACOKINETICS

Onset 12-72 hr

INTERACTIONS

• 
Toxicity:
mineral oil

Drug/Herb

Increase:
laxative action—flax, senna

NURSING CONSIDERATIONS
Assess:

• 
Cause of constipation;
identify whether fluids, bulk, or exercise missing from lifestyle; constipating products

• 
Cramping, rectal bleeding, nausea, vomiting; if these occur, product should be discontinued

Perform/provide:

• 
Storage in cool environment; do not freeze

Evaluate:

• 
Therapeutic response: decrease in constipation

Teach patient/family:

• 
That normal bowel movements do not always occur daily

• 
Not to use in presence of abdominal pain, nausea, vomiting

• 
To notify prescriber if constipation unrelieved or if symptoms of electrolyte imbalance occur: muscle cramps, pain, weakness, dizziness, excessive thirst

• 
That product may take up to 3 days to soften stools

• 
To take oral preparations with a full glass of water (unless on fluid restrictions) and to increase fluid intake

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

dofetilide (Rx)

Tikosyn

Func. class.:
Antidysrhythmic (Class III)

ACTION:

Blocks cardiac ion channel carrying the rapid component of delayed potassium current; no effect on sodium channels

USES:

Atrial fibrillation, flutter, maintenance of normal sinus rhythm

CONTRAINDICATIONS:

Children, hypersensitivity, digoxin toxicity, aortic stenosis, pulmonary hypertension, severe renal disease

 

Black Box Warning:

QT prolongation, torsades de pointes, renal failure

Precautions:
Pregnancy (C), breastfeeding, AV block, bradycardia, electrolyte imbalance

 

Black Box Warning:

Renal disease, arrhythmias

DOSAGE AND ROUTES
Calculator
Conversion of atrial fibrillation/atrial flutter to normal sinus rhythm; maintenance therapy with highly symptomatic atrial fibrillation/atrial flutter of ≥1 week duration


Adult: PO
Individualize dosage based on renal function and QTc in a monitored facility. Refer to the step-by-step procedure for determining the initial dosage of dofetilide

Maintenance therapy of atrial fibrillation/atrial flutter after hospital discharge


Adult: PO
Continue dosage at discharge as from initial dosage titration. Individualize dosage based on renal function and QTc, which should be re-evaluated every 3 months or as medically warranted; if the QTc >500 msec (550 msec in patients with ventricular conduc
tion abnormalities) at any time, discontinue; carefully monitor until QTc returns to baseline; if renal function deteriorates, adjust the dosage as described in the dosage guidelines for patients with renal impairment.

Discontinuation of dofetilide before use of interacting drugs


Adult: PO
Discontinue dofetilide for ≥2 days before starting a potentially interacting drug

Renal dose


Adult: PO
CCr >60 ml/min, 500 mcg bid; CCr 40-60 ml/min, 250 mcg bid; CCr 20-39 ml/min, 125 mcg bid; CCr <20 ml/min, do not use

Available forms:
Caps 125, 250, 500 mcg

Administer:

 

Black Box Warning:

Step 1: Assess cardiac conduction:
Before first dose, the QTc interval must be determined using an average of 5–10 beats; if the QTc interval is >440 msec (or >500 msec in ventricular conduction abnormalities), do not use. If baseline heart rate is <60 bpm, then the QT interval should be used

 

Black Box Warning:

Step 2: Assess renal function:
Before first dose, determine renal function using the Cockroft-Gault equation, use actual body weight to calculate creatinine clearance

 

Black Box Warning:

Step 3: Adjust starting dose according to renal function:
Refer to the “Patients with renal impairment” section (below) to determine the appropriate initial dosage

 

Black Box Warning:

Step 4: ECG monitoring:
Begin continuous ECG monitoring starting with the first dose

 

Black Box Warning:

Step 5: Dosage adjustments:
Approximately 2–3 hr after the first dose, determine the QTc interval. If the QTc interval has increased by >15% (compared to baseline), or if the QTc interval is >500 msec (>550 msec in patients with ventricular conduction abnormalities), the initial dosage should be reduced by half as follows:

• 
Decrease an initial dose of 500 mcg bid to 250 mcg bid

• 
Decrease an initial dose of 250 mcg bid to 125 mcg bid

• 
Decrease an initial dose of 125 mcg bid to 125 mcg/day

 

Black Box Warning:

Step 6: Reassess QTc interval:
Reassess the QTc interval 2–3 hr after each subsequent dose; if the QTc interval lengthens to >500 msec (or >550 msec in patients with ventricular conduction abnormalities),
discontinue

 

Black Box Warning:

Step 7: ECG monitoring:
Monitor continuous ECG for a minimum of 3 days or for 12 hr after conversion to normal sinus rhythm, whichever is greater

SIDE EFFECTS

CNS:
Syncope, dizziness
, headache,
stroke

CV:
Hypotension, postural hypotension, bradycardia
, angina, PVCs, substernal pressure, transient hypertension, precipitation of angina,
QT prolongation, torsades de pointes, ventricular dysrhythmias

GI:
Nausea, vomiting
, severe diarrhea, anorexia

MISC:
Angioedema

RESP:
Dyspnea, respiratory infections

PHARMACOKINETICS

Well absorbed, max plasma conc 2-3 hr, steady state 2-3 days, half-life 10 hr, metabolized by liver, excreted by kidneys

INTERACTIONS


 
Do not use with cimetidine, ketoconazole, verapamil, prochlorperazine, trimethoprim-sulfamethoxazole, megestrol, hydrochlorothiazide

Increase:
QT prolongation, torsades de pointes—class IA/III antidysrhythmics, arsenic trioxide, chloroquine, clarithromycin, droperidol, erythromycin, halofantrine, haloperidol, levomethadyl, methadone, pentamidine, some phenothiazines, ziprasidone

Increase:
hypokalemia—potassium-depleting diuretics

Increase:
toxicity—amiloride metFORMIN, entecavir, lamiVUDine, memantine, triamterene, procainamide, trospium

Increase:
dofetilide levels—antiretroviral protease inhibitors

Drug/Food

• 
Do not use with grapefruit juice

NURSING CONSIDERATIONS
Assess:


 
AF patients should receive anticoagulation prior to cardioversion

• 
Cardiac status: rate, rhythm, character, continuously; B/P

 

Black Box Warning:

Severe renal impairment CCr <20 ml/min:
do not use for mild to moderate renal disease; monitor BUN/creatinine; adjust dose based on creatinine clearance

Perform/provide:

• 
Place patient in supine position unless otherwise ordered; assist with ambulation

Evaluate:

• 
Therapeutic response: control of atrial fibrillation

Teach patient/family:

• 
To make position changes slowly; orthostatic hypotension may occur


 
To notify prescriber if fast heartbeats with fainting or dizziness occur

• 
To notify all prescribers of all medications, supplements taken

• 
That if dose is missed, not to double; to take next dose at usual time

• 
To avoid breastfeeding

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