Card Set Information

2011-06-27 18:56:42

Show Answers:

  1. Class:
    • Calcium Channel Blocker
    • Class IV antidysrhythmic
  2. Mechanism of Action:
    • Diltiazem inhibits the influx of extracellular calcium across both the myocardial and vascular smooth muscle cell membranes. Resulting in dilation of the coronary and systemic arteries; improved oxygen delivery to the myocardial tissue; and decreased total peripheral resistance, systemic blood pressure, and afterload.
    • It is a negative dromotrope & creates refractoriness in the AV node. Its effects on calcium channels in SA and AV nodes, and peripheral vasculature are equipotent.
  3. Indications:
    • Atrial fibrillation & atrial flutter with a rapid ventricular response
    • Multifocal atrial tachycardia
    • PSVT
  4. Contraindications:
    • 2nd or 3rd degree AV block (in the absence of a functioning pacemaker)
    • Sick Sinus Syndrome (in the absence of a functioning pacemaker)
    • Cardiogenic shock
    • Hypersensitivity
    • Atrial fibrillation or atrial flutter associated with WPW or short PR syndrome (Lown-Ganong-Levine Syndrome)
    • Ventricular tachycardia
    • Wide-complex tachycardia of unknown origin
    • AMI (associated with CHF or left ventricular dysfunction)
    • Advanced aortic stenosis
    • Hypotension (less than 90 mmHg)
  5. Precautions:
    • CHF
    • Elderly
    • Renal / Hepatic Impairment
    • Pregnancy (C)
  6. Dosage: Adults:
    DOSE: IV: 10 mg slow over 2 minutes. Repeat every 10-15 minutes PRN rate control. MAX 40 mg.
  7. Pediatrics:
    • Rarely required, doses are the same as adult.
    • (Medical Control Order) 0.25 mg/kg IV over 2 minutes (Usual dose about 20 mg). May repeat in 15 minutes @ 0.35 mg/kg IV over 2 minutes
  8. Onset:
    2-5 minutes
  9. Duration:
    1-3 hours
  10. Side Effects:
    • First or second degree AV block
    • Bradycardia
    • Ventricular dysrhythmias
    • CHF, Edema
    • Hypotension, Syncope
    • Flushing
    • Chest pain
    • Dyspnea
    • Sweating
    • N/V
    • Dizziness
    • Nervousness
    • Xerostomia
    • HA
  11. Interactions:
    • May prolong the sedative effects of midazolam.
    • May enhance the effects of ASA and prolong bleeding time.
    • Additive effects with antihypertensives, alpha-blockers, & diuretics.
    • Should not be used in combination with IV beta-blockers. The negative inotropic, chronotropic, & hypotensive effects can induce heart failure.
    • Calcium salts can antagonize the hypotensive effects, but do not seem to have an effect on AV conduction.
    • Incompatible with simultaneous furosemide injection.
  12. PEARLS:
    • As always, unstable tachycardias with serious signs or symptoms warrant cardioversion.
    • Hypotension may result and warrants careful monitoring of vital signs.
    • PVCs may be present on conversion of PSVT to sinus rhythm.
    • Medical Control may order (occasionally, physician preference) a pretreatment of calcium chloride for hypotensive or borderline hypotensive patients.
    • Infusions are often not required prehospital with abbreviated transport times. Bolus Diltiazem has (in some studies) been shown to maintain therapeutic levels for 24-48 hours.
    • AHA dosing for adults: 0.25 mg/kg IV over 2 minutes (Usual dose about 20 mg). May repeat in 10-15 minutes @ 0.35 mg/kg IV over 2 minutes .