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| ==Dosage And Administration== | | ==Dosage And Administration== |
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| Labetalol hydrochloride injection is intended for intravenous use in hospitalized patients. DOSAGE MUST BE INDIVIDUALIZED depending upon the severity of hypertension and the response of the patient during dosing.
| | DOSAGE MUST BE INDIVIDUALIZED. The recommended initial dosage is 100 mg twice daily whether used alone or added to a diuretic regimen. After 2 or 3 days, using standing blood pressure as an indicator, dosage may be titrated in increments of 100 mg b.i.d. every 2 or 3 days. The usual maintenance dosage of labetalol HCl is between 200 and 400 mg twice daily. |
| | Since the full antihypertensive effect of labetalol HCl is usually seen within the first 1 to 3 hours of the initial dose or dose increment, the assurance of a lack of an exaggerated hypotensive response can be clinically established in the office setting. The antihypertensive effects of continued dosing can be measured at subsequent visits, approximately 12 hours after a dose, to determine whether further titration is necessary. |
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| Patients should always be kept in a supine position during the period of intravenous drug administration. A substantial fall in blood pressure on standing should be expected in these patients. The patient’s ability to tolerate an upright position should be established before permitting any ambulation, such as using toilet facilities. | | Patients with severe hypertension may require from 1,200 to 2,400 mg per day, with or without thiazide diuretics. Should side effects (principally nausea or dizziness) occur with these doses administered twice daily, the same total daily dose administered three times daily may improve tolerability and facilitate further titration. Titration increments should not exceed 200 mg twice daily. |
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| Either of two methods of administration of labetalol hydrochloride injection may be used: a) repeated intravenous injections, b) slow continuous infusion.
| | When a diuretic is added, an additive antihypertensive effect can be expected. In some cases this may necessitate a labetalol HCl dosage adjustment. As with most antihypertensive drugs, optimal dosages of labetalol hydrochloride tablets are usually lower in patients also receiving a diuretic. |
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| ===Repeated Intravenous Injection===
| | When transferring patients from other antihypertensive drugs, labetalol hydrochloride tablets should be introduced as recommended and the dosage of the existing therapy progressively decreased. |
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| Initially, labetalol hydrochloride injection should be given in a dose of 20 mg labetalol HCl (which corresponds to 0.25 mg/kg for an 80 kg patient) by slow intravenous injection over a 2-minute period.
| | Elderly Patients: As in the general patient population, labetalol therapy may be initiated at 100 mg twice daily and titrated upwards in increments of 100 mg b.i.d. as required for control of blood pressure. Since some elderly patients eliminate labetalol more slowly, however, adequate control of blood pressure may be achieved at a lower maintenance dosage compared to the general population. The majority of elderly patients will require between 100 and 200 mg b.i.d.<ref name="dailymed.nlm.nih.gov">{{Cite web | last = | first = | title = LABETALOL HYDROCHLORIDE TABLET, FILM COATED [WATSON LABORATORIES, INC.] | url = http://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=a5b65a9b-6b8a-48a4-9c72-0e605bb309eb | publisher = | date = | accessdate = 5 February 2014 }}</ref> |
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| Immediately before the injection and at 5 and 10 minutes after injection, supine blood pressure should be measured to evaluate response. Additional injections of 40 mg or 80 mg can be given at 10 minute intervals until a desired supine blood pressure is achieved or a total of 300 mg labetalol HCl has been injected. The maximum effect usually occurs within 5 minutes of each injection.
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| ===Slow Continuous Infusion===
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| Labetalol hydrochloride injection is prepared for continuous intravenous infusion by diluting the contents with commonly used intravenous fluids (see below). Examples of methods of preparing the infusion solution are:
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| The contents of either two 20 mL vials (40 mL), or one 40 mL vial, are added to 160 mL of a commonly used intravenous fluid such that the resultant 200 mL of solution contains 200 mg of labetalol hydrochloride, 1 mg/mL. The diluted solution should be administered at a rate of 2 mL/min to deliver 2 mg/min.
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| Alternatively, the contents of either two 20 mL vials (40 mL), or one 40 mL vial, of labetalol hydrochloride injection are added to 250 mL of a commonly used intravenous fluid. The resultant solution will contain 200 mg of labetalol hydrochloride, approximately 2 mg/3 mL. The diluted solution should be administered at a rate of 3 mL/min to deliver approximately 2 mg/min.
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| The rate of infusion of the diluted solution may be adjusted according to the blood pressure response, at the discretion of the physician. To facilitate a desired rate of infusion, the diluted solution can be infused using a controlled administration mechanism, e.g., graduated burette or mechanically driven infusion pump.
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| Since the half-life of labetalol is 5 to 8 hours, steady-state blood levels (in the face of a constant rate of infusion) would not be reached during the usual infusion time period. The infusion should be continued until a satisfactory response is obtained and should then be stopped and oral labetalol hydrochloride started. The effective intravenous dose is usually in the range of 50 to 200 mg. A total dose of up to 300 mg may be required in some patients. | |
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| ===Blood Pressure Monitoring===
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| The blood pressure should be monitored during and after completion of the infusion or intravenous injections. Rapid or excessive falls in either systolic or diastolic blood pressure during intravenous treatment should be avoided. In patients with excessive systolic hypertension, the decrease in systolic pressure should be used as indicator of effectiveness in addition to the response of the diastolic pressure.
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| ===Initiation of Dosing with Labetalol Hydrochloride Tablets===
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| Subsequent oral dosing with labetalol hydrochloride tablets should begin when it has been established that the supine diastolic blood pressure has begun to rise. The recommended initial dose is 200 mg, followed in 6 to 12 hours by an additional dose of 200 or 400 mg, depending on the blood pressure response. Thereafter, inpatient titration with labetalol hydrochloride tablets may proceed as follows:
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| While in the hospital, the dosage of labetalol hydrochloride tablets may be increased at 1 day intervals to achieve the desired blood pressure reduction.
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| For subsequent outpatient titration or maintenance dosing see Labetalol Hydrochloride Tablets Product Information DOSAGE AND ADMINISTRATION for additional recommendations.
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| ===Compatibility with commonly used intravenous fluids===
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| Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.
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| Labetalol hydrochloride injection was tested for compatibility with commonly used intravenous fluids at final concentrations of 1.25 mg to 3.75 mg labetalol hydrochloride per mL of the mixture. Labetalol hydrochloride injection was found to be compatible with and stable (for 24 hours refrigerated or at room temperature) in mixtures with the following solutions:
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| Ringers Injection, USP
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| Lactated Ringers Injection, USP
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| 5% Dextrose and Ringers Injection
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| 5% Lactated Ringers and 5% Dextrose Injection
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| 5% Dextrose Injection, USP
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| 0.9% Sodium Chloride Injection, USP
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| 5% Dextrose and 0.2% Sodium Chloride Injection, USP
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| 2.5% Dextrose and 0.45% Sodium Chloride Injection, USP
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| 5% Dextrose and 0.9% Sodium Chloride Injection, USP
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| 5% Dextrose and 0.33% Sodium Chloride Injection, USP
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| Labetalol hydrochloride injection was NOT compatible with 5% Sodium Bicarbonate Injection, USP. Care should be taken when administering alkaline drugs, including furosemide, in combination with labetalol. Compatibility should be assured prior to administering these drugs together.<ref name="dailymed.nlm.nih.gov">{{Cite web | last = | first = | title = LABETALOL HYDROCHLORIDE INJECTION, SOLUTION [HOSPIRA, INC.] | url =http://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=abfc6b75-1ed5-41f1-0484-4597488237bc | publisher = | date = | accessdate = 5 February 2014 }}</ref>
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sheng Shi, M.D. [2]
Dosage And Administration
DOSAGE MUST BE INDIVIDUALIZED. The recommended initial dosage is 100 mg twice daily whether used alone or added to a diuretic regimen. After 2 or 3 days, using standing blood pressure as an indicator, dosage may be titrated in increments of 100 mg b.i.d. every 2 or 3 days. The usual maintenance dosage of labetalol HCl is between 200 and 400 mg twice daily.
Since the full antihypertensive effect of labetalol HCl is usually seen within the first 1 to 3 hours of the initial dose or dose increment, the assurance of a lack of an exaggerated hypotensive response can be clinically established in the office setting. The antihypertensive effects of continued dosing can be measured at subsequent visits, approximately 12 hours after a dose, to determine whether further titration is necessary.
Patients with severe hypertension may require from 1,200 to 2,400 mg per day, with or without thiazide diuretics. Should side effects (principally nausea or dizziness) occur with these doses administered twice daily, the same total daily dose administered three times daily may improve tolerability and facilitate further titration. Titration increments should not exceed 200 mg twice daily.
When a diuretic is added, an additive antihypertensive effect can be expected. In some cases this may necessitate a labetalol HCl dosage adjustment. As with most antihypertensive drugs, optimal dosages of labetalol hydrochloride tablets are usually lower in patients also receiving a diuretic.
When transferring patients from other antihypertensive drugs, labetalol hydrochloride tablets should be introduced as recommended and the dosage of the existing therapy progressively decreased.
Elderly Patients: As in the general patient population, labetalol therapy may be initiated at 100 mg twice daily and titrated upwards in increments of 100 mg b.i.d. as required for control of blood pressure. Since some elderly patients eliminate labetalol more slowly, however, adequate control of blood pressure may be achieved at a lower maintenance dosage compared to the general population. The majority of elderly patients will require between 100 and 200 mg b.i.d.[1]