Nitrostat
Nitrostat
Generic Name
Nitrostat
Brand Names
for the oral nitrate *nitroglycerin*, commonly used for the rapid relief of acute anginal episodes and for long‑term management of stable angina.
Mechanism
Nitrostat is a prodrug that is enzymatically converted to *nitric oxide (NO)* in vascular tissues.
• NO activates soluble guanylate cyclase → ↑ cyclic GMP → smooth‑muscle relaxation → vasodilation.
• Predominantly decreases preload (reduces left‑ventricular filling pressure).
• At higher doses, it also lowers afterload (decreases systemic vascular resistance).
• The result is a drop in myocardial oxygen demand, providing fast relief of ischemic chest pain.
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Pharmacokinetics
| Parameter | Details |
| Form | Immediate‑release tablet (5–10 mg) |
| Absorption | Oral; 20–25 % bioavailability (first‑pass hepatic & GI metabolism) |
| Peak plasma concentration (Tmax) | 30–60 min (food delays Tmax by ~15 min) |
| Half‑life | 2–4 h (active metabolites prolong biological effect) |
| Metabolism | Primarily hepatic sulfation; minor CYP‑mediated oxidation |
| Excretion | Renal (urine 30 %; feces 25 %) |
| Drug interactions | Potentiated hypotension with sildenafil, tadalafil, vardenafil, etc.; avoided with alcohol (enhanced vasodilatory effect). |
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Indications
- Stable angina pectoris – as needed or scheduled for episodes.
- Unstable angina – for rapid relief while awaiting further therapy.
- Prone to exercise‑induced angina – intermittent short‑term prophylaxis.
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Contraindications
- Absolute contraindications
- Severe hypotension (SBP < 90 mm Hg).
- Known hypersensitivity to nitrates.
- Recent use of *PDE5 inhibitors* (sildenafil, tadalafil, vardenafil).
- Relative contraindications
- Severe anemia (low BP from reduced oxygen delivery).
- Recent intracranial hemorrhage or stroke.
- Pregnancy (data limited).
- Warnings
- Nitrate tolerance: continuous exposure > 48 h leads to diminished effect.
- Myocardial infarction: may mask pain; use with caution.
- Hypertrophic obstructive cardiomyopathy: risk of worsening obstruction from preload reduction.
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Dosing
| Situation | Dose | Frequency | Notes |
| Acute angina/pain | 5–10 mg | PO as needed (2–3 mg every 5–10 min) | Administer while seated; repeat up to 2–3 times. |
| Maintenance (stable angina) | 5–10 mg | BID → TID | Gradual titration; do not exceed 30 mg/day. |
| Loading (excessive episodes) | 5–10 mg | Q6 h (every 6 h) | Aim for 90 % of maintenance dose within 24 h. |
| Renal/hepatic impairment | Reduce dose by 25–50 % | Adjust per clinic protocol | No dose adjustment for mild hepatic impairment. |
| Co‑administration with alcohol | Avoid simultaneous intake | Alcohol enhances vasodilation → hypotension. |
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Adverse Effects
| Adverse Effect | Incidence | Key Notes |
| Headache | 20–35 % | Vascular constriction; relieved by acetaminophen. |
| Flushing | 10–20 % | Transient; dose tapering helps. |
| Hypotension / Dizziness | 5–15 % | First‑dose phenomenon; monitor BP. |
| Nausea / GI upset | 2–5 % | Take with food to reduce symptoms. |
| Tachycardia | < 5 % | Reflex response to hypotension. |
| Methemoglobinemia | < 0.01 % | Rare; symptoms: cyanosis, dyspnea. |
| Serious | Various | Syncope, severe CNS depression, severe hypotension, severe allergic reaction. |
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Monitoring
- Blood pressure & heart rate → before first dose and at 30 min thereafter.
- Tolerability → observe for headache, flushing, nausea.
- Metabolic panel → in prolonged use (renal/liver function).
- Methemoglobin levels → if signs of cyanosis or unexplained dyspnea.
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Clinical Pearls
- Popping Method – For patients who require more than 2–3 doses for an anginal episode, “pop” the extra tablets together with the first dose to deliver a larger NO burst, reducing total number of doses needed.
- Nitrate‑Free Interval – Ensure at least a 10‑hour gap between last dose and bedtime to prevent tolerance; daily dosing schedules should incorporate this pause.
- Use with Calcium‑Channel Blockers – Combining with verapamil or diltiazem amplifies preload reduction; titrate carefully to avoid hypotension.
- Avoid in Rapid‑Transit Conditions – In patients with vomiting/diarrhea > 12 h, hold dosing until vomiting stops to prevent GI loss and under‑dosing.
- Patient Education – Emphasize that Nitrostat is for acute relief, not for routine prevention; scheduled nitrates should be taken at the same time each day.
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• References (for further reading)
• Katzung BG. “Basic & Clinical Pharmacology.” 14th ed. McGraw‑Hill, 2023.
• UpToDate. “Oral nitrates for ischemic chest pain” – latest review (2025).
• European Society of Cardiology Guidelines on Coronary Artery Disease, 2024.