Beta Blocker (IV) for Hypertension (Critical Care Formulary)

TAM (Treatments and Medicines) NHS Highland
NHS Highland

Audience

  • Highland Health and Social Care Partnership only
  • Critical Care areas only
  • Adults only

General Information

USES:

  • To lower blood pressure in resistant hypertensive states
  • Rate control in atrial fibrillation
  • Where beta-blocker clinically indicated and oral route unavailable.

CONTRAINDICATIONS:

  • Asthma
  • Cardiogenic shock
  • Uncontrolled heart failure
  • Second or third degree heart block
  • Untreated phaeochromocytoma
  • Metabolic acidosis.

CAUTIONS:

  • First degree heart block
  • Concurrent administration with other rate lowering drugs
  • There are rare reports of hepatocellular injury - monitor liver function for any signs of hepatic dysfunction
  • Hypotension
  • Bradycardia < 50bpm
  • Severe peripheral circulatory disturbances.

SIDE EFFECTS:

  • Bradycardia: seek medical advice if excessive bradycardia (HR< 50) persists.
  • Peripheral Coldness.
  • Bronchospasm.

MONITORING:

  • Continuous ECG and blood pressure monitoring required, ideally via arterial line
  • Respiratory function
  • Discontinue if HR < 50bpm or precipitous drop in BP.

NOTES:

If the maximum dose of one beta-blocker has been reached, do not use another beta-blocker. Instead consider using an alternative agent. Seek advice from Consultant Anaesthetist.

Labetalol - Central

Administer via CENTRAL line
For peripheral administration, see separate guideline

MECHANISM OF ACTION:

  • Non-cardioselective beta-blocker.
  • Also has selective alpha-1 blocking properties which decrease peripheral vascular resistance to lower blood pressure.
  • Ratio of alpha- to beta-blocking activity estimated at 1:7 after intravenous dosing.
  • Half-life approximately 4 hours.

INDICATIONS:

  • Urgent blood pressure lowering.

PRESENTATION:

  • 20mL ampoules containing labetalol 5mg in 1mL.

ADMINISTATION:

  • For bolus:
    • Give undiluted over at least 1 minute.
  • For infusion (CENTRAL VENOUS ADMINISTRATION ONLY):
    • Draw 3 vials (60mL) into a syringe.
    • Deliver the 5mg in 1mL neat solution via a syringe driver.

DOSE & RATE:

Hypertensive Emergency, by infusion: Target BP as set by consultant
  • Start infusion at 0.5mg/minute: 6mL/hour if using 5mg in 1mL via CVC.
  • Follow flow chart below to guide dose titration and tapering.

Thrombolysis in Acute Stroke, by bolus: Target BP < 185/110mmHg
  • Use undiluted 5mg in 1mL: if slow administration required, consider using diluted solution (see below).
  • Start with 2 to 5mg bolus over 1 to 2 minutes.
  • If BP still > 185/110mmHg, give further IV boluses of increasing dose every 5 minutes.
  • Further doses as follows: 10mg, 20mg, 40mg then repeat 40mg to a maximum total dose of 300mg in 24 hours.
  • Boluses to be administered by (or directly supervised by) a doctor.
  • Continue until BP < 185/110mmHg or outwith time window for thrombolysis.
  • If maximum dose administered and BP still > 185/110mmHg GTN infusion can be used.
  • If contra-indication to labetalol, use GTN infusion.

Aortic dissection, by bolus or infusion: Target systolic BP 110 to 120mgHg
  • Commence infusion at 2mg/minute: 24mL/hour if using 5mg in 1mL via CVC.
  • Continue until target BP achieved then stop.
  • OR incremental IV boluses starting at 10 to 20mg every 5 to 10 minutes.

Myocardial infarction, by infusion: Target BP as set by consultant
  • Commence at 15mg per hour - 3mL/hour if using 5mg in 1mL via CVC.
  • Gradually increase to a maximum of 120mg per hour (24mL/hr) depending on control of blood pressure.

Hypertension in pregnancy (eclampsia/pre-eclampsia), by bolus or infusion: Target BP < 150/105mmHg
  • If pre-eclampsia, use oral if tolerated (200mg tablet). If eclampsia (seizures), will need IV labetalol but first give magnesium sulphate. See “Obstetric Emergencies” document on ED website and Magnesium Infusion Protocol for details.
  • Use undiluted due to strict fluid restriction in these patients (ideally via CVC, otherwise large peripheral vein with close monitoring).
  • 50mg bolus over 1 minute, repeat every 20 minutes to total 200mg.
  • OR infusion starting at 20 to 40mg/hour (4 to 8mL/hour) doubled every 30 minutes to maximum 160mg/hour (32mL/hour).

STABILITY:

  • Expiry time: 24 hours.
  • When administering by continuous infusion, do not allow infusion to run out. A new syringe or infusion may be prepared up to one hour before it is due to run out, and clearly labelled.

EXTRAVASATION

  • Labetalol has a low pH and may cause venous irritation and tissue damage in cases of extravasation. If a central venous access device is unavailable, administer via a large peripheral vein and monitor injection site closely. Re-site cannula at first signs of inflammation.

ADDITIONAL INFORMATION

  • Labetalol has a long half-life (4 to 8.3 hours) and the infusion does not need to be tapered to low rates before discontinuation.
  • When weaning the infusion, consideration can be given to stopping the infusion once 0.5mg/minute has been reached.  Otherwise, if concerned, can first reduce to 0.25mg/minute for 30 minutes, and then if patient’s blood pressure is still below target, can stop infusion.
  • Intravenous 10mg = Oral 100mg.
  • Labetalol 5mg in 1mL concentration can be used for peripheral bolus administration but is not suitable for continuous infusion through peripheral lines.  Only consider in hypertension in eclampsia if a CVC cannot be inserted, use a large peripheral vein and monitor closely for extravasation
  • The patient should remain supine during the infusion and for 3 hours after discontinuation of an intravenous infusion, due to risk of postural hypotension.
  • Doses above 2mg/minute are considered high and consideration should be given to discussing the patient with the consultant as titration continues up to 4mg/minute.  There is potential to increase rate up to 6mg/minute but this should be on specific recommendation of the consultant only and reduced when able.

Labetalol - Peripheral

Administer via PERIPHERAL line.
For central administration see separate guideline.

MECHANISM OF ACTION:

  • Non-cardioselective beta-blocker.
  • Also has selective alpha-1 blocking properties which decrease peripheral vascular resistance to lower blood pressure.
  • Ratio of alpha- to beta-blocking activity estimated at 1:7 after intravenous dosing.
  • Half-life approximately 4 hours.

INDICATIONS:

  • Urgent blood pressure lowering.

PRESENTATION:

  • 20mL ampoules containing labetalol 5mg in 1mL.

ADMINISTATION:

  • For bolus (peripheral or central administration)
    • Give undiluted over at least 1 minute.
  • For infusion (peripheral administration):
    • Dilute to 1mg in 1mL with glucose 5% or sodium chloride 0.9%.
    • Remove 100mL from a 500mL bag and add 500mg (100mL or 5 ampoules) of labetalol 5mg in 1mL injection.

DOSE & RATE:

Hypertensive Emergency, by infusion: Target BP as set by consultant
  • Start infusion at 0.5mg/minute - 30mL/hour as using 1mg in 1mL via PVC.
  • Follow flow chart below to guide dose titration and tapering.

Thrombolysis in Acute Stroke, by bolus: Target BP < 185/110mmHg
  • Dilute to 1mg in 1mL to aid slow administration.
  • Start with 2 to 5mg bolus over 1 to 2 minutes.
  •  If BP still > 185/110mmHg, give further IV boluses of increasing dose every 5 minutes.
  • Further doses as follows: 10mg, 20mg, 40mg then repeat 40mg to a maximum total dose of 300mg in 24 hours.
  • Boluses to be administered by (or directly supervised by) a doctor.
  • Continue until BP < 185/110mmHg or outwith time window for thrombolysis.
  • If maximum dose administered and BP still > 185/110mmHg GTN infusion can be used.
  • If contra-indication to labetalol, use GTN infusion.

Aortic dissection, by bolus or infusion: Target systolic BP 110 to 120mgHg
  • Commence infusion at 2mg/minute: 120mL/hour as using 1mg in 1mL via PVC.
  • Continue until target BP achieved then stop.
  • OR incremental IV boluses starting at 10 to 20mg every 5 to 10 minutes to a maximum total dose of 200mg in 24 hours.
  • If maximum bolus dose administered and BP still above target, consider switching to an alternative anti-hypertensive agent.

Myocardial infarction, by infusion: Target BP as set by consultant
  • Commence at 15mg per hour: 15mL/hour if using 1mg in 1mL via PVC.
  • Gradually increase to a maximum of 120mg per hour (120mL/hr) depending on control of blood pressure.

Hypertension in pregnancy (eclampsia/pre-eclampsia), by bolus or infusion: Target BP < 150/105mmHg
  • If pre-eclampsia, use oral if tolerated (200mg tablet). If eclampsia (seizures), will need IV labetalol but first give magnesium sulphate. See “Obstetric Emergencies” document on ED website and Magnesium Infusion Protocol for details.
  • Use undiluted due to strict fluid restriction in these patients (ideally via CVC, otherwise large peripheral vein with close monitoring).
  • 50mg bolus over 1 minute, repeat every 20 minutes to total 200mg.
  • OR infusion starting at 20 to 40mg/hour (20 to 40mL/hour as using 1mg in 1mL), doubled every 30 minutes to maximum 160mg/hour (160mL/hour).

STABILITY:

  • Expiry time: 24 hours
  • When administering by continuous infusion, do not allow infusion to run out. A new syringe or infusion may be prepared up to one hour before it is due to run out, and clearly labelled.

EXTRAVASATION

  • Labetalol has a low pH and may cause venous irritation and tissue damage in cases of extravasation. If a central venous access device is unavailable, administer via a large peripheral vein and monitor injection site closely. Re-site cannula at first signs of inflammation.

ADDITIONAL INFORMATION

  • Labetalol has a long half-life (4 to 8.3 hours) and the infusion does not need to be tapered to low rates before discontinuation.
  • When weaning the infusion, consideration can be given to stopping the infusion once 0.5mg/minute has been reach. Otherwise, if concerned, can first reduce to 0.25mg/minute for 30minutes, and then, if patient’s blood pressure is still below target, can stop infusion.
  • Intravenous 10mg = Oral 100mg
  • Labetalol 5mg in 1mL concentration can be used for peripheral bolus administration but is not suitable for continuous infusion through peripheral lines. Only consider in hypertension in eclampsia if a CVC cannot be inserted, use a large peripheral vein and monitor closely for extravasation
  • The patient should remain supine during the infusion and for 3 hours after discontinuation of an intravenous infusion, due to risk of postural hypotension
  • Doses above 2mg/min are considered high and consideration should be given to discussing the patient with the consultant as titration continues up to 4mg/minute. There is potential to increase rate up to 6mg/minute but this should be on specific recommendation of the consultant only and reduced when able.

Metoprolol

Administer via CENTRAL or PERIPHERAL line

MECHANISM OF ACTION:

  • Metoprolol lowers the blood pressure due to competitive beta-adrenoceptor antagonist. It acts preferentially to inhibit beta-adrenoceptors (conferring some cardioselectivity); it is devoid of intrinsic sympathomimetic activity.
  • Half-life approximately 3.5 hours.

PRESENTATION:

  • 5mL ampoules containing metoprolol 1mg in 1mL.

ADMINISTATION:

  • Bolus undiluted at a rate of 1 to 2mg per minute.

DOSE & RATE:

  • Titrate dose to achieve clinical systolic blood pressure target. This target should be specified by Consultant Anaesthetist.
  • Bolus 5mg dose and wait 10 minutes for effects. Consider lower initial bolus in elderly or frail patients.
  • If heart rate and blood pressure not at target, give another 5mg, up to a maximum of 15mg as directed by medical staff.
  • Once stabilised, try and switch to appropriate oral beta blocker.
  • If oral route is unavailable, give lowest effective dose every 6 to 8 hours.

ADDITIONAL INFORMATION

  • Intravenous 1mg = Oral 2.5mg.
  • Metoprolol is metabolised through the CYP2D6 enzyme. 10% of patients may be overly sensitive and 10% may respond poorly to its effects.

Atenolol

Administer via CENTRAL or PERIPHERAL line

MECHANISM OF ACTION:

  • It is beta1-selective, (ie acts preferentially on beta1-adrenergic receptors in the heart). Selectivity decreases with increasing dose.
  • Atenolol is without intrinsic sympathomimetic and membrane-stabilising activities and as with other beta-blockers, has negative inotropic effects.
  • Half-life approximately 6 hours.

PRESENTATION:

  • 10mL ampoules containing atenolol 0.5mg in 1mL.

ADMINISTATION:

  • Bolus undiluted over 2.5 minutes.

DOSE & RATE:

  • Titrate dose to achieve clinical systolic blood pressure target. This target should be specified by Consultant Anaesthetist.
  • Bolus 2.5mg to 5mg dose and wait 10 minutes for effects. Consider lower initial bolus dose (2.5mg or less) in elderly/frail patients, particularly if impaired renal function (see Additional Information); and higher dose if resistant hypertension or patient previously on beta-blockers.
  • Wait 10 minutes, if heart rate and blood pressure still not under control, give another 2.5mg to 5mg up to a maximum of 10mg.
  • Once stabilised, try and switch to appropriate oral beta-blocker.
  • If oral route is unavailable, give lowest effective dose every 12 hours. In patients with CrCl < 35mL/min/1.73m2, accumulation is possible and interval between doses should be extended. Discuss with pharmacy for further advice.

ADDITIONAL INFORMATION:

Intravenous 1mg = Oral 10mg.

Appendix 1: Example Prescription and Rate Adjustments for Continuous Infusion of Labetalol (5mg/ml)

For an example labetolol intravenous infusion prescription, click here.

BIBLIOGRAPHY

BRITISH MEDICAL ASSOCIATION AND THE ROYAL PHARMACEUTICAL SOCIETY OF GREAT BRITAIN, 2022. British National Formulary (BNF) 83. London: BMJ Publishing Group Ltd and RPS Publishing

ELECTRONIC MEDICINES COMPENDIUM (EMC), 2020. Summary of Product Characteristics – Labetalol 5mg/ml. [online]. Surrey: Datapharm Ltd. Available from: https://www.medicines.org.uk/emc/product/9165/smpc#gref  [Accessed 27 July 2022]

ELECTRONIC MEDICINES COMPENDIUM (EMC), 2020. Summary of Product Characteristics – Metoprolol 1mg/ml. [online]. Surrey: Datapharm Ltd. Available from: https://www.medicines.org.uk/emc/product/866/smpc#gref [Accessed 29 July 2022]

ELECTRONIC MEDICINES COMPENDIUM (EMC), 2020. Summary of Product Characteristics – Tenormin Injection 0.5 mg/ml. [online]. Surrey: Datapharm Ltd. Available from: https://www.medicines.org.uk/emc/product/5499/smpc#gref [Accessed 3 August 2022]

NATIONAL HEALTH SERVICE, MEDUSA: NHS Injectable Medicines Guide [online]. Accessed via: https://medusa.wales.nhs.uk/ [Accessed 29 July 2022]

MACINNES, N; 2021. Labetalol IV. [online]. Inverness: NHS Highland. Available from: http://intranet.nhsh.scot.nhs.uk/Org/DHS/SSU/MedicalDir/EmergencyDepartmentNEW/MASTER%20LIBRARY/02%20Emergency%20drugs%20sedation%20anaesthesia%20Guidance/Adult/Adult%2018%20-%20Labetalol%20v%201.0.pdf#search=labetalol. [Accessed 12 December 2022]

JORDAN UNIVERSITY OF SCIENCE & TECHNOLOGY, 2013 Labetalol. [online]. Iribid: JUST. Available from: https://www.just.edu.jo/DIC/AZLibrary/Labetalol.pdf [Accessed 8 September 2022]

JORDAN UNIVERSITY OF SCIENCE & TECHNOLOGY, 2013 Metoprolol. [online]. Iribid: JUST. Available from:  https://www.just.edu.jo/DIC/AZLibrary/Metoprolol.pdf [Accessed 8 September 2022]

JORDAN UNIVERSITY OF SCIENCE & TECHNOLOGY, 2013 Atenolol. [online]. Iribid: JUST. Available from:  https://www.just.edu.jo/DIC/AZLibrary/atenolol.pdf [Accessed 8 September 2022]

Editorial Information

Last reviewed: 27/04/2023

Next review date: 27/04/2026

Author(s): Critical Care Formulary Development Group.

Version: 1.2

Approved By: TAM Subgroup

Reviewer name(s): Jane Wylie and Chris Bland.

Document Id: AF001