NITRO-BID

Clinical safety rating: caution

Comprehensive clinical and safety monograph for NITRO-BID (NITRO-BID).

How it works

Nitroglycerin is a nitrate that relaxes vascular smooth muscle by conversion to nitric oxide (NO), which activates guanylate cyclase, increasing cyclic guanosine monophosphate (cGMP) levels, leading to vasodilation. Primarily dilates veins, reducing preload and myocardial oxygen demand; also dilates coronary arteries.

What the body does with it

Metabolism	Rapidly metabolized via hepatic glutathione-organic nitrate reductase to dinitrates and mononitrates; also metabolized in erythrocytes and vascular tissue.
Excretion	Renal: <1% unchanged; extensive metabolism followed by renal excretion of metabolites, with minor biliary/fecal elimination (<5%).
Half-life	Terminal half-life of nitroglycerin is 1-4 minutes; clinical effects are short-lived due to rapid redistribution and metabolism.
Protein binding	Approximately 60% bound to plasma proteins (mainly albumin).
Volume of Distribution	Vd approximately 3.3 L/kg, indicating extensive distribution into tissues beyond plasma volume.
Bioavailability	Sublingual: ~40% (high first-pass hepatic metabolism); Transdermal: ~72% (bypasses first-pass); Oral: <10% due to extensive hepatic metabolism.
Onset of Action	Sublingual: 1-3 minutes; Transdermal: 30-60 minutes; Intravenous: immediate (1-2 minutes); Topical (ointment): 15-30 minutes.
Duration of Action	Sublingual: 30-60 minutes; Transdermal: up to 12 hours with patch removal; Intravenous: as long as infusion continues; Topical: 3-6 hours.

Classification & Brands

Action Class	Urinary Antiseptic-Nitrofurantoin
Brand Substitutes	Utab 100mg Tablet SR, Nitrobest Tablet SR, Utichek 100mg Tablet SR, Nifutin Tablet SR, Nifnext SR Tablet

Dosing & administration

Sublingual: 0.3-0.6 mg at onset of angina, may repeat every 5 minutes up to 3 doses. Transdermal: 0.2-0.8 mg/hour patch applied daily for 12-14 hours, then removed for 10-12 hours.

Dosage form	INJECTABLE
Renal impairment	No specific adjustment required; nitroglycerin is minimally renally excreted.
Liver impairment	Child-Pugh A: no adjustment. Child-Pugh B: consider dose reduction (25-50% of normal dose). Child-Pugh C: avoid or use with extreme caution; reduce dose by 50% or more.
Pediatric use	Not routinely recommended; limited data. Intravenous: start at 0.25-0.5 mcg/kg/min, titrate by 0.5-1 mcg/kg/min every 3-5 min to effect; max 5 mcg/kg/min.
Geriatric use	Start at lower end of dosing range due to increased sensitivity and risk of hypotension. Sublingual: 0.3 mg initial. Transdermal: 0.2 mg/hour initially.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for NITRO-BID (NITRO-BID).

Breastfeeding	Excreted in breast milk in small amounts; M/P ratio approximately 0.5. Although risk to infant appears low, caution is advised. Monitor infant for hypotension, methemoglobinemia (rare).
Teratogenic Risk	Pregnancy Category C. Animal studies have shown fetal harm (bradycardia, reduced birth weight). Inadequate human data for first trimester; avoid unless benefit outweighs risk. Second and third trimesters: associated with maternal hypotension and fetal bradycardia; use only if clearly needed.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

No FDA boxed warning specifically for NITRO-BID. However, nitroglycerin is contraindicated with phosphodiesterase-5 inhibitors (e.g., sildenafil) due to severe hypotension.

Side Effect Profile

Serious Effects

Absolute Contraindications

Hypersensitivity to nitrates; concurrent use with phosphodiesterase-5 inhibitors (e.g., sildenafil, tadalafil); severe anemia; increased intracranial pressure; circulatory failure or shock; right ventricular infarction; constrictive pericarditis; cardiac tamponade.

Clinical Precautions

Precautions

May cause severe hypotension, especially with volume depletion; avoid in patients with hypertrophic cardiomyopathy; use caution in hepatic/renal impairment; tolerance develops with chronic use; may aggravate angina when discontinuing abruptly.

Clinical Tips & Counseling

Drug interactions

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NITRO-BID

Clinical safety rating: caution

Comprehensive clinical and safety monograph for NITRO-BID (NITRO-BID).

How it works

What the body does with it

Metabolism	Rapidly metabolized via hepatic glutathione-organic nitrate reductase to dinitrates and mononitrates; also metabolized in erythrocytes and vascular tissue.
Excretion	Renal: <1% unchanged; extensive metabolism followed by renal excretion of metabolites, with minor biliary/fecal elimination (<5%).
Half-life	Terminal half-life of nitroglycerin is 1-4 minutes; clinical effects are short-lived due to rapid redistribution and metabolism.
Protein binding	Approximately 60% bound to plasma proteins (mainly albumin).
Volume of Distribution	Vd approximately 3.3 L/kg, indicating extensive distribution into tissues beyond plasma volume.
Bioavailability	Sublingual: ~40% (high first-pass hepatic metabolism); Transdermal: ~72% (bypasses first-pass); Oral: <10% due to extensive hepatic metabolism.
Onset of Action	Sublingual: 1-3 minutes; Transdermal: 30-60 minutes; Intravenous: immediate (1-2 minutes); Topical (ointment): 15-30 minutes.
Duration of Action	Sublingual: 30-60 minutes; Transdermal: up to 12 hours with patch removal; Intravenous: as long as infusion continues; Topical: 3-6 hours.

Classification & Brands

Action Class	Urinary Antiseptic-Nitrofurantoin
Brand Substitutes	Utab 100mg Tablet SR, Nitrobest Tablet SR, Utichek 100mg Tablet SR, Nifutin Tablet SR, Nifnext SR Tablet

Dosing & administration

Sublingual: 0.3-0.6 mg at onset of angina, may repeat every 5 minutes up to 3 doses. Transdermal: 0.2-0.8 mg/hour patch applied daily for 12-14 hours, then removed for 10-12 hours.

Dosage form	INJECTABLE
Renal impairment	No specific adjustment required; nitroglycerin is minimally renally excreted.
Liver impairment	Child-Pugh A: no adjustment. Child-Pugh B: consider dose reduction (25-50% of normal dose). Child-Pugh C: avoid or use with extreme caution; reduce dose by 50% or more.
Pediatric use	Not routinely recommended; limited data. Intravenous: start at 0.25-0.5 mcg/kg/min, titrate by 0.5-1 mcg/kg/min every 3-5 min to effect; max 5 mcg/kg/min.
Geriatric use	Start at lower end of dosing range due to increased sensitivity and risk of hypotension. Sublingual: 0.3 mg initial. Transdermal: 0.2 mg/hour initially.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for NITRO-BID (NITRO-BID).

Breastfeeding	Excreted in breast milk in small amounts; M/P ratio approximately 0.5. Although risk to infant appears low, caution is advised. Monitor infant for hypotension, methemoglobinemia (rare).
Teratogenic Risk	Pregnancy Category C. Animal studies have shown fetal harm (bradycardia, reduced birth weight). Inadequate human data for first trimester; avoid unless benefit outweighs risk. Second and third trimesters: associated with maternal hypotension and fetal bradycardia; use only if clearly needed.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

No FDA boxed warning specifically for NITRO-BID. However, nitroglycerin is contraindicated with phosphodiesterase-5 inhibitors (e.g., sildenafil) due to severe hypotension.