Generic Name

Bystolic

Mechanism

• Beta‑adrenergic blockade (β1 and β2): ↓ cardiac contractility and heart rate → reduces myocardial oxygen demand.
• Alpha‑1‑adrenergic blockade: ↓ vascular smooth‑muscle tone → peripheral vasodilation, lowering systemic vascular resistance.
• The combined effects yield a rapid, potent fall in blood pressure without significant reflex tachycardia.

Pharmacokinetics

• Absorption: Oral bioavailability ~95 %.
• Distribution: 40–60 % protein bound.
• Metabolism: Predominantly hepatic via CYP3A4/2D6 to inactive metabolites.
• Half‑life: 4–6 h (oral); 5–7 h (IV).
• Excretion: Renal (≈50 %) and biliary.
• Drug interactions: Inhibition of CYP3A4 (e.g., ketoconazole) may elevate levels; CYP2D6 inhibitors (e.g., fluoxetine) can also increase exposure.

Indications

• Acute hypertensive emergencies (e.g., severe sustained hypertension, preeclampsia, eclampsia).
• Hypertension with rapid onset or when a fast‑acting agent is needed.
• Pheochromocytoma peri‑operative management.
• Pre‑eclampsia to prevent maternal complications.

Contraindications

• Absolute contraindications:
• Severe bradycardia or heart block (unless with pacemaker).
• Cardiogenic shock, severe aortic stenosis.
• Relative contraindications:
• Asthma or chronic obstructive pulmonary disease.
• Severe hepatic or renal impairment.
• Special warnings:
• Pregnancy: Category C → use only if benefits outweigh risks.
• Elderly: Increase sensitivity to hypotension; titrate slowly.
• Co‑administration with other antihypertensives may lead to additive hypotension.

Dosing

• Titration: Aim for a 20–25 % fall in systolic BP within 30 min; avoid exceeding 30 % reduction to prevent cerebral ischemia.
• Discontinuation: Stop IV abruptly after converting to oral therapy to avoid rebound hypertension.

Adverse Effects

• Common (≤10 %): dizziness, headache, tinnitus, flushing, fatigue, constipation.
• Serious (rare): reflex bradycardia, heart block, orthostatic hypotension, severe allergic reactions, metabolic disturbances (hyperglycemia in diabetics).
• Monitoring for:
• Arrhythmias (especially in patients with conduction defects).
• Hypoglycemia in diabetics (β2 blockade masks adrenergic symptoms).
• Liver function abnormalities with prolonged high dosing.

Monitoring

• Blood pressure: every 15 min during IV infusion; twice daily thereafter.
• Heart rate & rhythm: continuous telemetry for at least 24 h.
• Serum electrolytes (Na⁺, K⁺, Mg²⁺) periodically.
• Renal & hepatic panels every 48 h during high‑dose or prolonged therapy.
• Glucose levels for diabetic patients during the first 48 h.
• Lactate & arterial blood gases in patients with impaired perfusion.

Clinical Pearls

• Rapid titration—Administer 0.2 mg/kg IV over 2 min, then titrate every 5 min to maintain target BP; this reduces the risk of over‑ or under‑dosing.
• Use in pregnancy—When treating severe preeclampsia, Bystolic provides the fastest onset while also offering β‑blocker benefits (reduced tachycardia) without significant placental transfer.
• Avoid when possible co‑administration with other β‑blockers (e.g., metoprolol) unless specifically indicated; the additive β‑blockade can precipitate severe hypotension or bradycardia.
• Renal impairment—Since ~50 % is renally excreted, reduce dose by 25 % if creatinine clearance <30 mL/min; monitor closely.
• Pre‑operative use in pheochromocytoma—Starting oral therapy 7–10 days pre‑op and converting to IV infusion on the day of surgery ensures optimal blood pressure control and reduces operative hemorrhage risk.

Key takeaway: Bystolic is a versatile anti‑hypertensive with rapid onset and dual α1/β blockade—ideal for emergency settings, but requires vigilant dose titration and monitoring to prevent hypotension, bradycardia, and other adverse events.