Labetalol
BASICS: DOSAGE:
• Antihypertensive - alpha and beta blocker ORAL: Initial dose—100mg b.d. increased by 100mg b.d. at
weekly intervals
• POM
• In 2nd and 3rd trimester - can be titrated to t.d.s.
• Tablets, ampoules between 100-400mg
• Oral or IV injection/infusion • Can have up to 800mg evenly divided into 3-4
doses
• Maximum 2.4g in 24 hours
IV injection: 50mg over 1 min, repeated after 5 min
IV infusion: 20mg/hour doubled after 30 minutes
SIDE EFFECTS: PHARMACODYNAMICS:
• Postural hypotension, tiredness, • Works by blocking peripheral arteriolar
weakness, epigastric pain, difficulty with alpha receptors and this reduces
micturition, tremor, scalp irritation. peripheral resistance
INTERACTIONS: • Concurrent beta-blockade protects the
heart from reflux effects
• Anaesthetics—enhance hypotension
• Cardiac output is not significantly reduced
• Antidiabetics—enhance hypoglycaemic
at rest or after moderate exercise
effect
• Ergometrine—increase vasoconstrictions
CONTRAINDICATIONS: FETAL/BREASTFEEDING RISK:
• Asthma • Only in 1st trimester if benefits outweigh
the risks as beta blockers reduce
• Wheezing
placental perfusion leading to risk of IUD,
• Hypersensitivity
premature delivery, IUGR, neonatal
• Bradycardia hypoglycaemia, respiratory depression and
• Heart block jaundice
• Raynaud’s disease • Excreted in BM, manufacturers advise
avoidance but no known adverse side
• Chronic obstructive airway disease
effects
BASICS: DOSAGE:
• Antihypertensive - alpha and beta blocker ORAL: Initial dose—100mg b.d. increased by 100mg b.d. at
weekly intervals
• POM
• In 2nd and 3rd trimester - can be titrated to t.d.s.
• Tablets, ampoules between 100-400mg
• Oral or IV injection/infusion • Can have up to 800mg evenly divided into 3-4
doses
• Maximum 2.4g in 24 hours
IV injection: 50mg over 1 min, repeated after 5 min
IV infusion: 20mg/hour doubled after 30 minutes
SIDE EFFECTS: PHARMACODYNAMICS:
• Postural hypotension, tiredness, • Works by blocking peripheral arteriolar
weakness, epigastric pain, difficulty with alpha receptors and this reduces
micturition, tremor, scalp irritation. peripheral resistance
INTERACTIONS: • Concurrent beta-blockade protects the
heart from reflux effects
• Anaesthetics—enhance hypotension
• Cardiac output is not significantly reduced
• Antidiabetics—enhance hypoglycaemic
at rest or after moderate exercise
effect
• Ergometrine—increase vasoconstrictions
CONTRAINDICATIONS: FETAL/BREASTFEEDING RISK:
• Asthma • Only in 1st trimester if benefits outweigh
the risks as beta blockers reduce
• Wheezing
placental perfusion leading to risk of IUD,
• Hypersensitivity
premature delivery, IUGR, neonatal
• Bradycardia hypoglycaemia, respiratory depression and
• Heart block jaundice
• Raynaud’s disease • Excreted in BM, manufacturers advise
avoidance but no known adverse side
• Chronic obstructive airway disease
effects
