DiltiazemNursing considerations

Side effects by what to assess

Sources: [1][2][3][4][5]

ALT (liver enzyme)

Why

Acute hepatic injury

When

At regular intervals with oral therapy

Normal

4 to 36 U/L.

Sources: [1][2][3]

Blood pressure

Why

Hypotension during IV therapy; antihypertensive response

When

Frequently during IV therapy; regularly with oral therapy

Act on

Symptomatic hypotension on IV: saline or the Trendelenburg position

Normal

Below 120/80 mm Hg.

Sources: [1][2][3][4]

Digoxin level

Why

Diltiazem can raise digoxin levels

When

When starting, adjusting, or stopping diltiazem

Normal

Target 0.8 to 2.0 ng/mL.

Sources: [1][2]

ECG (rhythm and QT interval)

Why

AV block and conversion of PSVT

When

Continuous during IV therapy

Act on

High-degree AV block in sinus rhythm: stop IV diltiazem

Sources: [1][2]

Heart rate

Why

Response in atrial fibrillation or flutter; bradycardia

When

Continuously during IV therapy; regularly with oral therapy

Normal

60 to 100 beats per minute in adults at rest.

Sources: [1][2][3]

Serum creatinine

Why

Renal function, especially in older adults

When

At regular intervals with oral therapy

Normal

0.7 to 1.3 mg/dL in men and 0.5 to 0.95 mg/dL in women.

Sources: [1][2][3]

High-alert status

Diltiazem is not named on the ISMP acute care high-alert list, and calcium channel blockers are not a listed category.

Sources: [1]

Narrow therapeutic index

The labels do not describe a narrow therapeutic index or direct dosing by measured blood levels of the drug.

Sources: [1][2]

Boxed warning

None on the current labels.

Sources: [1][2]

Antidote or reversal

No specific antidote; give supportive care. Bradycardia or high-degree AV block: atropine (0.6 to 1 mg), then cautious isoproterenol if there is no response; fixed high-degree block needs pacing. Heart failure: inotropes (isoproterenol, dopamine, or dobutamine) and diuretics. Hypotension: vasopressors such as dopamine or norepinephrine. IV calcium (calcium chloride 1 g or calcium gluconate 3 g, each given over 5 minutes, with repeat doses every 10 to 20 minutes as needed) has given inconsistent results but improved the response to atropine in some cases; watch for hypercalcemia. Dialysis does not remove diltiazem.

Sources: [1][2]

Patient teaching

• Swallow the capsules whole; do not crush or chew them
• Take it at the same time each day and keep taking it when you feel well; it controls high blood pressure and angina but does not cure them
• It prevents chest pain but does not stop an attack; use your fast-acting medicine, such as nitroglycerin under the tongue, for that
• Avoid alcohol, which can make the capsule release the drug too fast
• Check your pulse as taught and call if it is slower than your target; report dizziness, fainting, or swelling of the feet or ankles
• Report yellow skin or eyes, pain in the upper right belly, rash, trouble breathing, or chest pain that gets worse or more frequent
• Tell every prescriber and pharmacist that you take diltiazem; it interacts with many drugs, including some statins and sedatives
• Do not stop it without talking to your prescriber

Sources: [1][2][3][4][5]

Sound-alike and look-alike names

• Cardizem and Cardene

Sources: [1]

Adult dose

IV, atrial fibrillation or flutter rate control, or PSVT conversion

0.25 mg/kg actual body weight IV over 2 minutes (20 mg for an average adult). If the response is inadequate after 15 minutes, give 0.35 mg/kg over 2 minutes (25 mg for an average adult). Some patients respond to 0.15 mg/kg.

IV infusion, continued rate control in atrial fibrillation or flutter

Start 10 mg/h right after the bolus (some patients respond to 5 mg/h). Increase in 5 mg/h steps up to 15 mg/h as needed, for no longer than 24 hours.

Cardizem CD, hypertension

Start 180 to 240 mg once daily. Usual range 240 to 360 mg once daily; some patients need up to 480 mg. Full effect by about 14 days.

Cardizem CD, angina

Start 120 or 180 mg once daily; titrate over 7 to 14 days up to 480 mg once daily as needed.

Sources: [1][2]

Renal adjustment

No labeled dose change. Renal impairment, even end-stage disease, did not appear to alter oral diltiazem disposition, but the labels advise caution in renal impairment and periodic renal function tests, especially in older adults. Dialysis does not remove it.

Sources: [1][2][3][4]

Hepatic adjustment

No labeled dose table. It is extensively metabolized by the liver; in cirrhosis the half-life rose and oral bioavailability increased 69%, so use caution and monitor liver tests. Acute hepatic injury has occurred, usually 1 to 8 weeks after starting, and reversed when the drug was stopped.

Sources: [1][2][3][4]

Mechanism

A non-dihydropyridine (benzothiazepine) calcium channel blocker. It inhibits calcium influx into cardiac and vascular smooth muscle during depolarization, which slows AV nodal conduction, prolongs AV nodal refractoriness (most at fast rates), and lengthens the sinus cycle; it has no significant effect on fast sodium channel tissue such as His-Purkinje fibers or accessory pathways. Vascular relaxation lowers peripheral resistance and blood pressure and dilates the coronary arteries, preventing spasm. IV: response within 3 minutes, peak heart rate effect in 2 to 7 minutes, half-life about 3.4 hours. Oral: about 40% bioavailable after extensive first-pass metabolism; it is a CYP3A4 substrate and inhibitor.

Sources: [1][2][3][4][5][6]