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.
Atrial fibrillation & atrial flutter with a rapid ventricular response
Multifocal atrial tachycardia
2nd or 3rd degree AV block (in the absence of a functioning pacemaker)
Sick Sinus Syndrome (in the absence of a functioning pacemaker)
Atrial fibrillation or atrial flutter associated with WPW or short PR syndrome (Lown-Ganong-Levine Syndrome)
Wide-complex tachycardia of unknown origin
AMI (associated with CHF or left ventricular dysfunction)
Advanced aortic stenosis
Hypotension (less than 90 mmHg)
Renal / Hepatic Impairment
DOSE: IV: 10 mg slow over 2 minutes. Repeat every 10-15 minutes PRN rate control. MAX 40 mg.
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
First or second degree AV block
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.
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 .