DILTIAZEM HYDROCHLORIDE IN 0.72% SODIUM CHLORIDE
Clinical safety rating: safe
No significant drug interactions Can cause hypernatremia and fluid overload.
Diltiazem inhibits calcium ion influx across cardiac and vascular smooth muscle cell membranes by binding to the L-type calcium channels, leading to coronary vasodilation, decreased myocardial contractility, and slowed AV nodal conduction.
| Metabolism | Extensively metabolized in the liver via CYP3A4; undergoes deacetylation, N-demethylation, and O-demethylation; metabolites include desacetyl-diltiazem (active). |
| Excretion | Renal: 2-4% unchanged; hepatic metabolism with biliary excretion; fecal elimination accounts for ~10% |
| Half-life | 3-4.5 hours; prolonged in hepatic impairment (up to 10 hours) and in elderly |
| Protein binding | 70-80% bound to albumin |
| Volume of Distribution | 5-8 L/kg; indicates extensive tissue binding |
| Bioavailability | Oral: ~40-50% due to first-pass metabolism; IV: 100% |
| Onset of Action | IV: 1-2 minutes; oral: 30-60 minutes |
| Duration of Action | IV: 1-4 hours (rate-dependent); oral SR: 12-24 hours |
Intravenous continuous infusion: 5-15 mg/hour (0.25-0.33 mg/kg per hour).
| Dosage form | SOLUTION |
| Renal impairment | No adjustment required for GFR >10 mL/min; for GFR <10 mL/min, use with caution and monitor heart rate. |
| Liver impairment | Child-Pugh Class A: reduce dose to 5-10 mg/hour; Child-Pugh Class B: reduce to 2.5-5 mg/hour; Child-Pugh Class C: avoid use. |
| Pediatric use | Children: 0.25-0.33 mg/kg/hour continuous IV infusion; maximum 15 mg/hour. |
| Geriatric use | Elderly: initial dose at lower end of range (5-10 mg/hour); titrate slowly due to increased sensitivity and risk of bradycardia. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
No significant drug interactions Can cause hypernatremia and fluid overload.
| FDA category | Animal |
| Breastfeeding | Diltiazem is excreted into human milk; milk-to-plasma ratio approximately 0.9. Limited data suggest low levels but potential for adverse effects in nursing infants (bradycardia, hypotension). Consider alternatives, especially while nursing a preterm or low-birth-weight infant. If used, monitor infant for signs of bradycardia and hypotension. |
| Teratogenic Risk |
■ FDA Black Box Warning
There is no FDA black box warning for diltiazem.
| Common Effects | fluid replacement |
| Serious Effects |
["Sick sinus syndrome (except with pacemaker)","Second- or third-degree AV block (except with pacemaker)","Severe hypotension (systolic <90 mmHg)","Acute myocardial infarction with pulmonary congestion","Hypersensitivity to diltiazem","Concurrent use with ivabradine"]
| Precautions | ["May cause bradycardia and AV block","Concomitant use with beta-blockers increases risk of bradycardia/heart failure","Avoid in patients with left ventricular dysfunction","May worsen heart failure in patients with reduced ejection fraction","Hepatic impairment requires dose adjustment","Monitor renal function in elderly; may cause hypotension","Avoid abrupt withdrawal"] |
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| No adequate studies in pregnant women. In animal studies, diltiazem has been associated with embryofetal toxicity (skeletal abnormalities, increased mortality) at doses >5 times the maximum recommended human dose. Use only if potential benefit justifies risk. First trimester: potential teratogen, avoid unless essential. Second and third trimesters: may cause uterine hypoperfusion and fetal hypoxia due to maternal hypotension; monitor fetal heart rate and uterine activity if used near term. |
| Fetal Monitoring | Monitor maternal blood pressure, heart rate, and ECG periodically. Assess for signs of heart block or hypotension. For fetal well-being: ultrasound to monitor growth and amniotic fluid volume; nonstress test and biophysical profile if used in second or third trimester. If used during labor, monitor uterine activity and fetal heart rate continuously. |
| Fertility Effects | No specific human studies on fertility; animal studies (rats) showed no impairment of fertility at doses up to 10 times the MRHD. However, calcium channel blockers may affect sperm function in vitro; relevance unclear. Overall, unlikely to cause significant fertility impairment in humans. |