TRIDIL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TRIDIL (TRIDIL).
Nitroglycerin is a vasodilator that acts directly on vascular smooth muscle, causing relaxation. It primarily dilates venous capacitance vessels, reducing preload, and at higher doses dilates arterioles, reducing afterload. The mechanism involves nitric oxide-mediated activation of guanylyl cyclase, increasing cGMP levels.
| Metabolism | Primarily hepatic metabolism via nitrate reductase, forming dinitrates and mononitrates. |
| Excretion | Renal (87% as inorganic nitrite/nitrate and metabolites), biliary/fecal (minimal, <1%) |
| Half-life | Terminal elimination half-life of nitroglycerin is 1-4 minutes; clinical effects are limited by rapid metabolism |
| Protein binding | 60% bound to plasma proteins (mainly albumin) |
| Volume of Distribution | 3.3 L/kg (large Vd indicating extensive tissue distribution) |
| Bioavailability | Intravenous: 100%; Sublingual: approximately 40% (first-pass metabolism); Transdermal: variable (70-80% systemic absorption with controlled delivery); Oral: <1% due to extensive hepatic first-pass effect |
| Onset of Action | Intravenous: 1-2 minutes; Sublingual: 1-3 minutes; Transdermal: 30-60 minutes; Topical ointment: 15-30 minutes |
| Duration of Action | Intravenous: 3-5 min after infusion cessation; Sublingual: 30-60 min; Transdermal: 8-12 hours (tolerance develops with continuous use); Topical: 3-6 hours |
| Molecular Weight | 227.09 |
Initial adult dose: 5 mcg/min IV via continuous infusion, titrated by 5 mcg/min every 3-5 minutes to achieve desired effect; usual therapeutic range 10-200 mcg/min.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment required for renal impairment; however, monitor for accumulation of thiocyanate (toxic metabolite) in patients with severe renal failure (CrCl <30 mL/min). |
| Liver impairment | Child-Pugh Class A: no adjustment; Class B and C: reduce initial dose by 50% and titrate cautiously due to reduced clearance. |
| Pediatric use | Initial: 0.25-0.5 mcg/kg/min IV; titrate by 0.5-1 mcg/kg/min every 3-5 minutes; usual range 1-5 mcg/kg/min; maximum 10 mcg/kg/min. |
| Geriatric use | Initiate at lower end of dosing range (e.g., 5 mcg/min) and titrate slowly; increased sensitivity and risk of hypotension; consider reduced initial dose (2.5-5 mcg/min). |
| 1st trimester | Tridil (nitroglycerin) is classified as FDA Pregnancy Category C. Limited human data; animal studies show risk. Use only if potential benefit justifies potential risk to the fetus. Reports of fetal bradycardia and hypotension with maternal use. |
| 2nd trimester | Same as T1: Category C. May cause fetal bradycardia and hypotension. Avoid use unless clearly needed. |
| 3rd trimester | Same as T1 and T2: Category C. Risk of fetal bradycardia, hypotension, and possibly uterine relaxation. Use only if clearly indicated. |
Clinical note
Comprehensive clinical and safety monograph for TRIDIL (TRIDIL).
| Placental transfer | Nitroglycerin crosses the placenta readily; fetal concentrations are about 10-15% of maternal levels. Studies show rapid placental transfer with potential fetal effects. |
| Breastfeeding | Nitroglycerin is excreted into breast milk in trace amounts considered insignificant. However, due to limited long-term data, use with caution and monitor infant for potential adverse effects (e.g., hypotension, methemoglobinemia). |
■ FDA Black Box Warning
Do not use in patients with erectile dysfunction using phosphodiesterase inhibitors (e.g., sildenafil, tadalafil) due to risk of severe hypotension.
| Serious Effects |
Hypersensitivity to nitroglycerin or any component of the formulationSevere anemiaIncreased intracranial pressure (e.g., head trauma, cerebral hemorrhage)Constrictive pericarditisPericardial tamponadeConcomitant use with phosphodiesterase-5 inhibitors (e.g., sildenafil, tadalafil, vardenafil) due to severe hypotension
| Precautions | Risk of severe hypotension, Can cause paradoxical bradycardia, May increase intracranial pressure, Tolerance may develop with prolonged use, Avoid in patients with hypovolemia |
| Food/Dietary | Avoid alcohol consumption during therapy as it can precipitate hypotension. No other specific food interactions are known. |
Loading safety data…
| Lactation Rating | L3 - Probably Compatible |
| Teratogenic Risk | Pregnancy Category C. No adequate studies in pregnant women. Nitroglycerin crosses the placenta. In animal studies, it caused fetal toxicity at high doses. Use only if clearly needed, weighing benefit against risk. Specific trimester risks: First trimester: limited data; potential for adverse effects based on animal studies. Second and third trimesters: may cause maternal hypotension and fetal bradycardia; avoid in cases of preeclampsia or volume depletion. |
| Fetal Monitoring | Continuous ECG and blood pressure monitoring during infusion. Assess for fetal heart rate abnormalities if used in pregnancy. Monitor for signs of methemoglobinemia (pulse oximetry, arterial blood gas with co-oximetry) with prolonged high doses. Monitor maternal heart rate, blood pressure, and symptoms of hypotension. Assess for headache, dizziness, or syncope. |
| Fertility Effects | No known effects on fertility in humans. Animal studies have not shown impaired fertility. No specific data on ovulatory or spermatogenic effects. |
| Clinical Pearls | Tridil (nitroglycerin) is primarily used for acute angina and perioperative hypertension. It must be administered via continuous IV infusion with non-PVC tubing and glass bottles due to drug adsorption to PVC. Monitor for hypotension, especially in hypovolemic patients; use with caution in inferior wall MI with right ventricular involvement. Tolerance can develop with prolonged infusion; use lowest effective dose and consider intermittent therapy. |
| Patient Advice | This medication is given intravenously to rapidly relieve chest pain or control blood pressure during surgery. · Report any headache, dizziness, or fainting immediately, as these may indicate low blood pressure. · Avoid alcohol and erectile dysfunction medications (e.g., sildenafil) while on this drug, as they can cause severe hypotension. · Do not stop the infusion abruptly; gradual dose reduction is required to prevent rebound angina. |