| Recommended Dose and Dosage Regimen | The recommended starting dose of labetalol for hypertension in adults is typically 100 mg taken orally twice daily. The dosage may be titrated based on blood pressure response, up to a maximum dose of 1200 mg per day. For hypertensive emergencies, intravenous labetalol may be administered at an initial dose of 20 mg, followed by additional doses as needed at 10-minute intervals, up to a maximum dose of 300 mg within a 2-hour period. Dosage adjustments should be made cautiously in patients with impaired hepatic or renal function. Follow your healthcare provider’s instructions regarding dosing. |
| Frequency of Administration | Labetalol is typically administered orally twice daily for the management of hypertension. In hypertensive emergencies, it may be given intravenously as needed. |
| Route of Administration | Labetalol is available for oral administration in the form of tablets, as well as for intravenous administration as a solution for injection or infusion. |
| Mechanism of Action (MOA) | Labetalol is a non-selective beta-blocker with additional alpha-1 blocking activity. It competitively blocks beta-adrenergic receptors, inhibiting the effects of catecholamines such as norepinephrine and epinephrine on the heart and peripheral vasculature. Labetalol also blocks alpha-1 adrenergic receptors, leading to vasodilation and further reduction in blood pressure. |
| Pharmacokinetics (PK) | Labetalol is well absorbed after oral administration, with peak plasma concentrations achieved within 1-2 hours. It undergoes extensive first-pass metabolism in the liver to inactive metabolites. The elimination half-life of labetalol is approximately 6-8 hours. Intravenous labetalol has a faster onset of action and shorter duration of effect compared to oral administration. |
| Pharmacodynamics (PD) | Labetalol exerts its pharmacodynamic effects by blocking beta-adrenergic receptors in the heart (beta-1 receptors) and peripheral vasculature (beta-2 receptors), leading to decreased heart rate, cardiac output, and peripheral vascular resistance. Additionally, labetalol blocks alpha-1 adrenergic receptors, causing vasodilation and further reduction in blood pressure. |
| Pathophysiology | Labetalol is indicated for the management of hypertension, including hypertension during pregnancy (eclampsia and severe preeclampsia), hypertensive emergencies, and hypertensive crisis. It is also used off-label for the treatment of migraine headaches and symptoms of hyperthyroidism. |
| Primary Indications | Hypertension, hypertensive emergencies, hypertensive crisis, hypertension during pregnancy (eclampsia, severe preeclampsia), off-label: migraine headaches, hyperthyroidism. |
| Contraindications | Contraindications to labetalol use include hypersensitivity to labetalol or its components, bronchial asthma or chronic obstructive pulmonary disease (COPD), severe bradycardia, second- or third-degree heart block, cardiogenic shock, decompensated heart failure, and severe hepatic impairment. Use caution in patients with diabetes, peripheral vascular disease, and thyrotoxicosis. |
| Purpose of Taking Medication | The purpose of labetalol therapy is to lower blood pressure by blocking beta-adrenergic receptors in the heart and peripheral vasculature, as well as alpha-1 adrenergic receptors, leading to decreased heart rate, cardiac output, and peripheral vascular resistance. Labetalol helps control hypertension and prevent associated complications. |
| Usage Instructions | Take labetalol exactly as prescribed by your healthcare provider. It is typically taken orally with or without food, as directed. Do not skip doses or stop taking labetalol abruptly without consulting your doctor, as this may lead to rebound hypertension or other adverse effects. |
| Precautions and Care | Patients taking labetalol should be monitored regularly for blood pressure control, heart rate, and signs of adverse effects such as bradycardia, hypotension, and exacerbation of heart failure. Use caution when discontinuing labetalol, as abrupt withdrawal may precipitate rebound hypertension or angina. |
| Dietary Considerations | There are no specific dietary restrictions associated with labetalol use. However, maintaining a heart-healthy diet low in sodium and saturated fats is important for overall cardiovascular health and blood pressure management. |
| Missed Dose | If a dose of labetalol is missed, take it as soon as you remember, unless it is almost time for your next dose. Do not double the dose to make up for a missed one. |
| Possible Side Effects | Common side effects of labetalol may include dizziness, fatigue, headache, nausea, and gastrointestinal disturbances. Serious adverse effects may include bradycardia, hypotension, heart block, exacerbation of heart failure, and bronchospasm. |
| Storage and Disposal | Store labetalol tablets at room temperature away from moisture and heat. Protect from light. Dispose of unused or expired medication according to local regulations. |
| Overdose or Emergency | In case of overdose, seek emergency medical attention or contact a poison control center immediately. Symptoms of labetalol overdose may include severe hypotension, bradycardia, heart block, and cardiac arrest. |
| Monitoring and Laboratory Tests | Patients taking labetalol may require regular monitoring of blood pressure, heart rate, and clinical response to treatment. Additional laboratory tests may be performed based on individual clinical needs and risk factors. |
