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Alpha- and Beta-Blocker (Antihypertensive) Pregnancy: UK SPC section 4.6: 'While no teratogenic effects have been demonstrated in animals, Labetalol should only be used during the first trimester of pregnancy if the potential benefits are likely to outweigh the possible risk to the foetus. Labetalol crosses the placental barrier and the possible consequences of alpha- and beta-adrenoceptor blockade in the foetus and neonate should be borne in mind. Perinatal and neonatal distress (bradycardia, hypotension, respiratory depression, hypoglycaemia, hypothermia) has been rarely reported. Sometimes these symptoms have developed a day or two after birth. Response to supportive measures (e.g. intravenous fluids and glucose) is usually prompt but with severe pre-eclampsia, particularly after prolonged intravenous labetalol, recovery may be slower. This may be related to diminished liver metabolism in premature babies. Beta-blockers reduce placental perfusion, which may result in intrauterine foetal death, immature and premature deliveries. There is an increased risk of cardiac and pulmonary complications in the neonate in the postnatal period. Intra-uterine and neonatal deaths have been reported with Labetalol but other drugs (e.g. vasodilators, respiratory depressants) and the effects of pre-eclampsia, intra-uterine growth retardation and prematurity were implicated. Such clinical experience warns against unduly prolonging high dose labetalol and delaying delivery and against co-administration of hydralazine.' Breast-feeding: labetalol is excreted in breast milk in small amounts (approximately 0.004% of the maternal dose); adverse events of unknown causality (sudden death syndrome, diarrhoea, hypoglycaemia) have been reported very rarely in breast-fed neonates; caution should be exercised.

Labetalol

Brand names: Trandate

Used in: Pre-eclampsia & Obstetric Emergencies

Labetalol, a combined alpha- and beta-adrenoceptor blocker, used as a first-line antihypertensive in pregnancy, including chronic and gestational hypertension and pre-eclampsia, available in oral and intravenous forms.

Adult dose

Dose: ORAL TABLETS ONLY - hypertension in pregnancy (this SPC does not cover intravenous use or rapid blood-pressure reduction): initial dosage 100 mg twice daily, increased if necessary at weekly intervals by 100 mg twice daily; during the second and third trimesters the severity of hypertension may necessitate a further titration to a three-times-daily regimen ranging from 100 mg - 400 mg three times a day.
Route: Oral (tablets, taken with food) - 'For oral administration only'
Frequency: Twice daily initially; three times daily if further titration is needed in the second and third trimesters
Max: 2400 mg/day (the pregnancy paragraph: 'The total daily dosage should not exceed 2400 mg')
SCOPE - ORAL ONLY. The pinned UK SPC (LABETALOL TABLETS BP 200 MG, Generics (U.K.) Limited T/A Viatris) is an oral-tablet label and states 'For oral administration only. Labetalol tablets should be taken with food.' The page lists the routes 'IV or Oral'; the INTRAVENOUS route is NOT covered by this SPC, so no intravenous bolus, repeat-bolus or infusion figure is given and none is endorsed here. This card does NOT cover acute severe hypertension that needs rapid intravenous control; use the injection SPC / local obstetric protocol for that. VERBATIM section 4.2: 'Hypertension in Pregnancy: An initial dosage of 100 mg twice daily may be increased, if necessary at weekly intervals by 100 mg twice daily. During the second and third trimesters, the severity of hypertension may necessitate a further dose titration to a three times daily regimen ranging from 100 mg - 400 mg three times a day. The total daily dosage should not exceed 2400 mg. Hospital in-patients with severe hypertension, particularly in pregnancy, may have daily increases in dosage.' STRENGTH (section 2): the pinned product is a 200 mg film-coated tablet (200 mg labetalol hydrochloride per tablet); the SPC states its doses in mg. DISTINCT FROM NON-PREGNANT ADULT HYPERTENSION (same section 4.2): initially 100 mg twice daily, increases of 100 mg twice daily at intervals of 14 days, 'Many patients blood pressure is controlled by 200 mg twice daily', up to 800 mg daily as a twice daily regimen, and in severe refractory hypertension up to 2400 mg daily in three or four divided doses. Elderly: an initial dose of 50 mg twice daily is recommended. Transfer from other antihypertensives: introduce labetalol at 100 mg twice daily and decrease the previous therapy gradually; abrupt withdrawal of clonidine or beta-blocking agents is undesirable. PAEDIATRIC: 'Labetalol is not recommended for use in children due to a lack of data on safety and efficacy.' OBSTETRIC CAUTIONS (section 4.6): labetalol crosses the placental barrier; perinatal and neonatal distress (bradycardia, hypotension, respiratory depression, hypoglycaemia, hypothermia) has been rarely reported and sometimes developed a day or two after birth; recovery may be slower in severe pre-eclampsia, particularly after prolonged intravenous labetalol; the SPC warns against unduly prolonging high-dose labetalol and delaying delivery, and against co-administration of hydralazine. Some sections of the product information we used were incomplete — check the full SPC. Text came from a PDF and has odd spacing in places.

Dose adjustments

Renal

UK SPC section 4.4: 'Patients with liver or kidney insufficiency may need a lower dosage, depending on the pharmacokinetic profile of the compound.' No numeric adjustment is given.

Hepatic

UK SPC section 4.4: severe hepatocellular injury has been reported with labetalol after both short-term and long-term treatment; at the first sign or symptom of liver dysfunction carry out laboratory testing, and if there is laboratory evidence of liver injury or the patient is jaundiced stop labetalol and do not re-start. 'Particular care should be taken when labetalol is used in patients with hepatic impairment as these patients metabolise labetalol more slowly than patients without hepatic impairment. Lower doses may be required.' No numeric adjustment is given.

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via MHRA Products — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to labetalol hydrochloride or to any of the tablet excipients (section 4.3)
  • Second or third degree heart block; sick sinus syndrome (including sino-atrial block) (section 4.3)
  • Cardiogenic shock; uncontrolled, incipient or digitalis-refractory heart failure (section 4.3)
  • Hypotension; bradycardia (<45-50 bpm) (section 4.3)
  • History of bronchospasm or chronic obstructive airways disease (section 4.3)
  • Untreated phaeochromocytoma; Prinzmetal's angina; severe peripheral circulatory disturbances (section 4.3)
  • Metabolic acidosis (e.g. in some diabetics); after prolonged fasting (section 4.3)

Side effects

  • Most side effects are transient and occur during the first few weeks of treatment (section 4.8)
  • Very common: positive antinuclear antibodies unassociated with disease. Common: hypersensitivity (rash, pruritus, angioedema and dyspnoea); dizziness; heart failure; raised liver function tests; tingling sensation in the scalp, usually transient, early in treatment; difficulty in micturition; ejaculatory failure, erectile dysfunction; drug fever (section 4.8)
  • Uncommon: bronchospasm (in patients with asthma or a history of asthma). Rare: bradycardia. Very rare: heart block; exacerbation of Raynaud's syndrome; jaundice (hepatocellular and cholestatic), hepatitis and hepatic necrosis; toxic myopathy; tremor has been reported in the treatment of hypertension of pregnancy (section 4.8)
  • Frequency not known: hyperkalaemia (particularly with impaired renal excretion of potassium), thrombocytopenia; depressed mood, lethargy, hallucinations, psychoses, confusion, sleep disturbances, nightmares; headache, tiredness; impaired vision, dry eyes; hypotension (postural hypotension is uncommon except at very high doses, or if the initial dose is too high or doses are increased too rapidly); ankle oedema, cold or cyanotic extremities, increase of an existing intermittent claudication; nasal congestion, interstitial lung disease; epigastric pain, nausea, vomiting, diarrhoea (section 4.8)
  • Frequency not known: sweating, reversible lichenoid rash, paraesthesia of the extremities, photosensitivity reactions, systemic lupus erythematosus, exacerbation of psoriasis, reversible alopecia; cramps; acute retention of urine; nipple pain and Raynaud's phenomenon of the nipple; masking of the symptoms of thyrotoxicosis or hypoglycaemia (section 4.8)
  • Skin rashes and/or dry eyes have been reported with beta-adrenoceptor blocking drugs; consider gradual discontinuance if not otherwise explicable (section 4.4)
  • Intraoperative Floppy Iris Syndrome during cataract surgery (class effect of alpha-1 blockers cannot be excluded) (section 4.4)

Interactions

  • Tricyclic antidepressants, barbiturates, phenothiazines and other antihypertensive agents potentiate the hypotensive action of labetalol; tricyclic antidepressants may increase the incidence of tremor (section 4.5)
  • Parenteral sympathomimetics such as adrenaline in patients on beta-blockers: in rare cases vasoconstriction, hypertension and bradycardia (sections 4.4, 4.5)
  • Verapamil, and to a lesser extent diltiazem: beta-blockers may enhance negative inotropic and chronotropic actions; concurrent use not recommended. Neither drug should be given intravenously within 48 hours of discontinuing the other (sections 4.4, 4.5)
  • Class 1 antiarrhythmics (disopyramide, quinidine, amiodarone): potentiating effect on atrial-conduction time and negative inotropic effect; care required (sections 4.4, 4.5)
  • Digitalis glycosides: should not be used with beta-blockers; may increase auriculo-ventricular conduction time (section 4.5)
  • Clonidine: non-selective beta-blockers increase the risk of rebound hypertension; continue clonidine for some time after the beta-blocker is stopped (section 4.5)
  • Monoamine oxidase inhibitors (except MAO-B inhibitors): should not be used concomitantly (section 4.5)
  • Anaesthetics: may attenuate reflex tachycardia and increase the risk of hypotension; inform the anaesthetist; avoid agents that cause myocardial depression such as cyclopropane and trichloroethylene (section 4.5)
  • Insulin and oral antidiabetic agents: hypoglycaemic effects may be enhanced and warning signs masked (sections 4.4, 4.5)
  • Cimetidine, hydralazine and alcohol increase the bioavailability of beta-blockers metabolised mainly by the liver (section 4.5)
  • Dihydropyridine derivatives such as nifedipine: increased risk of hypotension (section 4.5)
  • Prostaglandin synthetase inhibiting drugs may decrease the hypotensive effects of beta-blockers (section 4.5)
  • This interaction list may be incomplete — check the full SPC.

Monitoring

  • Blood pressure response, with dose titration at the intervals given in section 4.2; hospital in-patients with severe hypertension, particularly in pregnancy, may have daily increases in dosage (section 4.2)
  • Heart rate: if symptoms are attributable to a resting heart rate below 50-55 beats per minute, reduce the dose (section 4.4)
  • Liver function: at the first sign or symptom of liver dysfunction carry out appropriate laboratory testing; stop and do not restart if there is evidence of liver injury or jaundice (section 4.4)
  • Neonate: perinatal and neonatal distress (bradycardia, hypotension, respiratory depression, hypoglycaemia, hypothermia) has been rarely reported, sometimes a day or two after birth; supportive measures such as intravenous fluids and glucose usually give a prompt response (section 4.6)
  • Patients with diabetes: labetalol modifies the tachycardia of hypoglycaemia and may prolong the hypoglycaemic response to insulin (section 4.4)
  • Withdrawal in ischaemic heart disease should be gradual, over 1-2 weeks (section 4.4)

Clinical monograph

How it works

Labetalol blocks beta-adrenoceptors to reduce heart rate and cardiac output while also blocking alpha-1 receptors to cause vasodilatation, lowering blood pressure without a marked reflex tachycardia.

Prescribing in practice

  • It should be avoided in women with asthma because of the risk of bronchospasm, and beta-blockade can mask and modify hypoglycaemia, which is relevant in diabetic pregnancy and the neonate.
  • Neonates of treated mothers should be observed for bradycardia and hypoglycaemia after delivery.
  • It is a preferred oral and intravenous agent for hypertension in pregnancy and is used both for maintenance control and acute severe hypertension in a monitored setting.

Monitoring

Monitor maternal blood pressure and heart rate, and observe the neonate for hypoglycaemia and bradycardia following delivery.

Counselling the patient

  • Take this regularly to keep your blood pressure controlled and do not stop suddenly without advice.
  • Tell your midwife or doctor if you have asthma or wheezing, or if you feel dizzy on standing.
  • Your baby will be checked after birth for a slow heartbeat or low blood sugar.

Evidence & guidelines

NICE guidance on hypertension in pregnancy recommends labetalol as a first-line antihypertensive for chronic, gestational and pre-eclamptic hypertension.

Reference: RCOG Hypertension in Pregnancy Guideline; NICE NG133; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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