DILT-CD
Clinical safety rating
cautionComprehensive clinical and safety monograph for DILT-CD (DILT-CD).
Diltiazem inhibits calcium ion influx during depolarization of cardiac and vascular smooth muscle cells, thereby reducing intracellular calcium levels. It decreases sinoatrial and atrioventricular nodal conduction and dilates coronary and peripheral arteries.
| Metabolism | Hepatic via CYP3A4; undergoes deacetylation and N-demethylation. |
| Excretion | Renal 2-4% unchanged; extensive hepatic metabolism; 60-70% fecal, 30-40% renal as metabolites |
| Half-life | Terminal elimination half-life 7-10 hours; clinically relevant in hepatic impairment (prolonged to 14-20 hours) and in elderly |
| Protein binding | 85-90% bound to plasma proteins (primarily albumin and alpha-1-acid glycoprotein) |
| Volume of Distribution | 3-5 L/kg; large Vd indicates extensive tissue binding, with highest concentrations in liver, lung, and spleen |
| Bioavailability | Oral immediate-release: 40-60% (first-pass effect); oral sustained-release: 30-50%; IV: 100% |
| Onset of Action | Oral: 30-60 minutes (immediate-release); IV: 2-5 minutes; sustained-release: 2-3 hours |
| Duration of Action | Oral immediate-release: 6-8 hours; oral sustained-release: 12-24 hours; IV: 1-4 hours depending on infusion rate |
| Molecular Weight | 414.53 |
180-360 mg PO once daily (extended-release); 300-540 mg PO once daily for hypertension; 120-480 mg PO once daily for angina; IV: 0.25 mg/kg bolus over 2 min, then 5-15 mg/hr continuous infusion.
| Dosage form | CAPSULE, EXTENDED RELEASE |
| Renal impairment | No dosage adjustment required for mild-moderate renal impairment; use caution and consider dose reduction in severe renal impairment (CrCl <30 mL/min) due to potential accumulation. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 25-50%; Child-Pugh C: contraindicated or use with extreme caution, reduce dose by at least 50%. |
| Pediatric use | Not FDA-approved for pediatric use; off-label dosing for hypertension: extended-release initial 2.5-5 mg/kg/day PO once daily, max 10 mg/kg/day up to 360 mg daily; for supraventricular tachycardia: IV bolus 0.1-0.3 mg/kg over 2 min, may repeat after 30 min, max 10 mg/dose. |
| Geriatric use | Start at lower end of dosing range (e.g., 120 mg PO once daily for hypertension); titrate slowly; monitor for hypotension, bradycardia, and constipation; consider reduced initial dose due to altered pharmacokinetics. |
| 1st trimester | Avoid. Potential for fetal cardiovascular effects (calcium channel blockers may cause fetal hypoxia or metabolic disturbances). Limited human data; animal studies suggest risk. |
| 2nd trimester | Avoid. Use only if benefit outweighs risk due to potential for fetal hypotension and impaired placental perfusion. |
| 3rd trimester | Avoid. Risk of fetal hypoxia, metabolic acidosis, and neonatal hypotension at delivery. May suppress uterine contractions and prolong labor. |
Clinical note
Comprehensive clinical and safety monograph for DILT-CD (DILT-CD).
| Placental transfer | Extensively crosses the placenta. Achieves fetal plasma concentrations approximately 50-100% of maternal levels. |
| Breastfeeding | Diltiazem is excreted into human milk in low concentrations (milk:plasma ratio ~0.6-1.0). No adverse effects reported in infants, but caution advised due to potential for cardiovascular effects. Monitor infant for bradycardia, hypotension, and feeding difficulties. |
| Lactation Rating | L3 (Moderately Safe) - Limited data, potential risks. |
| Teratogenic Risk | DILT-CD is a formulation of diltiazem, a calcium channel blocker. In animal studies, diltiazem has been associated with fetal skeletal abnormalities and reduced fetal weight at high doses. Human data are limited; however, diltiazem is generally avoided in the first trimester due to potential teratogenic effects. In the second and third trimesters, use is cautioned due to risks of maternal hypotension and possible fetal hypoxia. Diltiazem crosses the placenta and may cause fetal bradycardia. |
| Fetal Monitoring | Monitor maternal blood pressure and heart rate regularly. Fetal heart rate monitoring is recommended given the risk of bradycardia. Assess fetal growth via ultrasound due to potential for intrauterine growth restriction (IUGR). Monitor for signs of maternal hypotension, especially when used with other antihypertensives. |
| Fertility Effects | Diltiazem has been associated with reversible decreases in sperm motility and count in animal studies. In humans, data are limited; however, calcium channel blockers may impair sperm function. No significant effects on female fertility are reported, but caution is warranted. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to diltiazem or any componentSick sinus syndrome (except in presence of functioning ventricular pacemaker)Second- or third-degree AV block (except in presence of functioning ventricular pacemaker)Severe hypotension (systolic <90 mmHg)Acute myocardial infarction with pulmonary congestionAtrial fibrillation/flutter associated with accessory bypass tract (e.g., WPW syndrome)
| Precautions | May cause bradycardia, heart block, or heart failure exacerbation, Use caution in patients with impaired left ventricular function, May cause hypotension, especially in patients with aortic stenosis, May increase digoxin and cyclosporine levels, Abrupt withdrawal may exacerbate angina, Hepatic impairment may require dose adjustment, Avoid use in patients with sick sinus syndrome or second/third-degree AV block without pacemaker |
| Food/Dietary | Avoid grapefruit and grapefruit juice; they inhibit CYP3A4 and increase diltiazem levels, raising risk of toxicity. High-fat meals may increase absorption; take with food to reduce gastrointestinal upset. Alcohol may enhance hypotension and dizziness; limit consumption. |
| Clinical Pearls | DILT-CD is a calcium channel blocker (non-dihydropyridine) used for hypertension and angina. It has negative chronotropic and dromotropic effects; avoid in patients with sick sinus syndrome or second/third-degree AV block without a pacemaker. Monitor heart rate and PR interval. May increase digoxin levels; co-administration requires dose adjustment. Contraindicated with IV beta-blockers due to risk of bradycardia and heart failure. |
| Patient Advice | Take exactly as prescribed; do not crush or chew extended-release capsules. · May cause dizziness or lightheadedness; avoid driving until you know how this medication affects you. · Report slow heartbeat, shortness of breath, or swelling in your ankles or feet. · Limit alcohol intake as it may increase side effects. · Avoid grapefruit and grapefruit juice as they can increase drug levels and side effects. |
Loading safety data…