Mosby's 2014 Nursing Drug Reference (418 page)

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verapamil (Rx)

(ver-ap′a-mill)

Apo-Verap
, Calan, Calan SR, Covera-HS
, Isoptin SR, Nu-Verap
, Verelan, Verelan PM

Func. class.:
Calcium channel blocker; antihypertensive; antianginal, antidysrhythmic (class IV)

Chem. class.:
Diphenylalkylamine

ACTION:

Inhibits calcium ion influx across cell membrane during cardiac depolarization; produces relaxation of coronary vascular smooth muscle; dilates coronary arteries; decreases SA/AV node conduction; dilates peripheral arteries

USES:

Chronic stable, vasospastic, unstable angina; dysrhythmias, hypertension, supraventricular tachycardia, atrial flutter or fibrillation

Unlabeled uses:
Prevention of migraine headaches, claudication, mania

CONTRAINDICATIONS:

Sick sinus syndrome, 2nd-/3rd-degree heart block, hypotension <90 mm Hg systolic, cardiogenic shock, severe CHF, Lown-Ganong-Levine syndrome, Wolff-Parkinson-White syndrome

Precautions:
Pregnancy (C), breastfeeding, children, geriatric patients, CHF, hypotension, hepatic injury, renal disease, concomitant β-blocker therapy

DOSAGE AND ROUTES
Calculator
Angina

• Adult:
PO
80-120 mg tid, increase weekly, max 480 mg/day

Dysrhythmias

• Adult:
PO
240-480 mg/day in 3-4 divided doses in digitalized patients

• Adult:
IV BOL
5-10 mg (0.075-0.15 mg/kg) over 2 min, may repeat 10 mg (0.15 mg/kg) 1/2 hr after 1st dose

• Child 1-15 yr:
IV BOL
0.1-0.3 mg/kg over ≥2 min, repeat in 30 min, max 5 mg in single dose

• Child 0-1 yr:
IV BOL
0.1-0.2 mg/kg over ≥2 min, may repeat after 30 min

Hypertension

• Adult:
PO
80 mg tid, may titrate upward;
EXT REL
120-240 mg/day as single dose, may increase to 240-480 mg/day

Hepatic disease/geriatric patients/ compromised ventricular function

• Adult:
PO
40 mg tid initially, increase as tolerated

Claudication due to PVD (unlabeled)

• Adult:
PO
120-480 mg/day in divided doses

Mania (unlabeled)

• Adult:
PO
160-320 mg/day in divided doses, may be given with lithium

Migraine prophylaxis (unlabeled)

• Adult:
PO
80 mg tid

Available forms:
Tabs 40, 80, 120 mg; ext rel tabs 120, 180, 240 mg; inj 2.5 mg/ml in ampules, syringes, vials; ext rel caps 100, 200, 240, 300 mg

Administer:
PO route

• 
Reg rel:
Give without regard to food

Ext rel route

• 
Do not crush or chew ext rel products; caps may be opened and contents sprinkled on food; do not dissolve chew cap contents

• 
Before meals, at bedtime; give ext rel product with food

Direct IV route

• 
Undiluted through
Y
-tube or 3-way stopcock of compatible sol; give over 2 min or 3 min for geriatric patients, with continuous ECG and B/P monitoring, discard unused solution

• 
Do not use IV with IV β-blockers, may cause AV nodal blockade

Y-site compatibilities:
Alfentanil, amikacin, argatroban, ascorbic acid, atracurium, atropine, aztreonam, bivalirudin, bumetanide, buprenorphine, butorphanol, calcium chloride/gluconate, CARBOplatin, caspofungin, ceFAZolin, cefonicid, cefotaxime, cefoTEtan, cefOXitin, ceftizoxime, cefTRIAXone, cefuroxime, chlorproMAZINE, cimetidine, ciprofloxacin, clindamycin, cyanocobalamin, cyclophosphamide, cycloSPORINE, cytarabine, DACTINomycin, DAPTOmycin, dexamethasone, dexmedetomidine, digoxin, diltiazem, diphenhydrAMINE, DOBUTamine, DOCEtaxel, DOPamine, doxacurium, DOXOrubicin hydrochloride, doxycycline, enalaprilat, ePHEDrine, EPINEPHrine, epirubicin, epoetin alfa, eptifibatide, erythromycin, esmolol, etoposide, etoposide phosphate, famotidine, fenoldopam, fentaNYL, fluconazole, fludarabine, gemcitabine, gentamicin, glycopyrrolate, granisetron, heparin, hydrALAZINE, hydrocortisone, HYDROmorphone, ifosfamide, imipenem/cilastatin, inamrinone, insulin, isoproterenol, ketorolac, labetalol, levofloxacin, lidocaine, linezolid, LORazepam, magnesium sulfate, mannitol, mechlorethamine, meperidine, metaraminol, methotrexate, methoxamine, methyldopate, methylPREDNISolone, metoclopramide, metoprolol, metroNIDAZOLE, miconazole, midazolam, milrinone, mitoXANtrone, morphine, multivitamins, nalbuphine, naloxone, nesiritide, nitroglycerin, nitroprusside, norepinephrine, octreotide, ondansetron, oxaliplatin, oxytocin, PACLitaxel, palonosetron, papaverine, PEMEtrexed, penicillin G, pentamidine, pentazocine, phentolamine, phenylephrine, phytonadione, piperacillin/tazobactam, potassium chloride, procainamide, prochlorperazine, promethazine, propranolol, protamine, pyridoxime, quinupristin/dalfopristin, ranitidine, rocuronium, sodium acetate, succinylcholine, SUFentanil, tacrolimus, teniposide, theophylline, thiamine, ticarcillin/clavulanate, tirofiban, tobramycin, tolazoline, trimethaphan, urokinase, vancomycin, vasopressin, vecuronium, vinCRIStine, vinorelbine, voriconazole

SIDE EFFECTS

CNS:
Headache, drowsiness
, dizziness, anxiety, depression, weakness, insomnia, confusion, lightheadedness, asthenia, fatigue

CV:
Edema
,
CHF,
bradycardia, hypotension, palpitations, AV block,
dysrhythmias

GI:
Nausea
, diarrhea, gastric upset,
constipation
, increased LFTs

GU:
Impotence, gynecomastia, nocturia, polyuria

HEMA:
Bruising, petechiae, bleeding

INTEG:
Rash, bruising

MISC:
Gingival hyperplasia

SYST:
Stevens-Johnson syndrome

PHARMACOKINETICS

Metabolized by liver, excreted in urine (70% as metabolites)

PO:
Onset variable; peak 3-4 hr; duration 17-24 hr; half-life (biphasic) 4 min, 3-7 hr (terminal)

IV:
Onset 3 min, peak 3-5 min, duration 10-20 min

INTERACTIONS

Increase:
hypotension—prazosin, quiNIDine, fentaNYL, other antihypertensives, nitrates

Increase:
effects of verapamil—β-blockers, cimetidine, clarithromycin, erythromycin, monitor for CV effects

Increase:
levels of digoxin, theophylline, cycloSPORINE, carBAMazepine, nondepolarizing muscle relaxants

Decrease:
effects of lithium

Decrease:
antihypertensive effects—NSAIDs

Drug/Food

Increase:
hypotensive effects—grapefruit juice

Drug/Herb

Increase:
verapamil effect—ginseng, ginkgo

Increase:
hypertension ephedra (ma huang)

Decrease:
verapamil effect—St. John’s wort

Drug/Lab Test

Increase:
AST, ALT, alk phos, BUN, creatinine, serum cholesterol

NURSING CONSIDERATIONS
Assess:

• 
Cardiac status:
B/P, pulse, respiration, ECG intervals (PR, QRS, QT); notify prescriber if pulse <50 bpm, systolic B/P <90 mm Hg

 
CHF:
I&O ratios, weight daily; crackles, weight gain, dyspnea, jugular venous distention

• 
Renal, hepatic studies during long-term treatment, serum potassium periodically

Evaluate:

• 
Therapeutic response: decreased anginal pain, decreased B/P, dysrhythmias

Teach patient/family:

• 
To increase fluids, fiber to counteract constipation

• 
How to take pulse, B/P before taking product; to keep record or graph

• 
To avoid hazardous activities until stabilized on product, dizziness no longer a problem

• 
To limit caffeine consumption; to avoid alcohol products

• 
To avoid OTC or grapefruit products unless directed by prescriber

• 
To comply with all areas of medical regimen: diet, exercise, stress reduction, product therapy

• 
To change positions slowly to prevent syncope

• 
Not to discontinue abruptly, chest pain may occur

 
To report chest pain, palpitations, irregular heart beats, swelling of extremities, skin irritation, rash, tremors, weakness

• 
To notify prescriber if pregnancy is planned; may breastfeed (American Academy of Pediatrics)

• 
That cap (Covera-HS)
may appear in stool

TREATMENT OF OVERDOSE:

Defibrillation, atropine for AV block, vasopressor for hypotension, IV calcium

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