Adrenaline
Severe
Textbook
Marked rise in BP.
Adrenaline should not be given to patients receiving β blockers.
Source: KDT 7e · p133
Drug reference
Labetalol
Non-selective beta-blocker with additional alpha-1 blocking activity · Antihypertensive
Also known as Labetalol hydrochloride
START
Check HR, BP (supine and standing). Baseline LFTs. Assess asthma/COPD history. Counsel on orthostatic hypotension—rise slowly from sitting/lying.
TYPICAL MAX
2400mg/day oral. Hepatotoxicity risk increases at higher doses—monitor LFTs. IV cumulative max 300mg for hypertensive emergency.
STOP IF
Severe hypotension, HR <50 bpm, acute hepatic injury (jaundice, LFTs >3x ULN), bronchospasm, heart block.
WATCH
Orthostatic BP at each visit (alpha-1 effect). Hepatotoxicity—immune-mediated hepatitis has been reported (rare but fatal); monitor LFTs. Tingling scalp is benign and transient with IV use. Do not stop abruptly—rebound hypertension risk.
CDSCO approvedATC C07AG01
KDIGO 2024 + manufacturer label
- ONSET
- 30min · Onset ~30 min
- PEAK
- 1.5h · Tmax 1-2 hours
- t½
- 6.5h · t½ ~5-8 hours
- DURATION
- 10h · 8-12 hours (oral)
EXCRETION
Fecal as metabolites (~55-60%)
route + CYP
INTERACTIONS
12 major
SEVERE in our sources
PREGNANCY
Preferred antihypertensive in pregnancy (with methyldopa and nifedipine). Extensive safety data in preeclampsia. May cause neonatal bradycardia and hypoglycemia if used near delivery—monitor newborn for 48-72h.
FDA category + note
Top interactionssee all 12 →
- AdrenalineSevereTextbookKDT 7e · p133
- AmilorideSevereTextbookKDT 7e
- SofosbuvirSevereTextbookHarrison 22e · unknown
- AminophyllineSevereDatabaseDDInter
Available in India
83 branded formulations. Look up specific brands in the Drugs workspace.
Mechanism
Competitive blockade of beta-1, beta-2, and alpha-1 adrenergic receptors. The alpha-1 blockade causes peripheral vasodilation (reduces afterload), while beta-blockade reduces heart rate and myocardial contractility. Ratio of alpha:beta blockade is 1:3 (oral) and 1:7 (IV).
Indications
Severe hypertension / hypertensive emergencies (IV)Chronic hypertension (oral)Hypertension in pregnancy (including preeclampsia/eclampsia—first-line)Hypertensive crisisClonidine withdrawal rebound hypertension
Dosing
- Adult
- Hypertension (oral): 100mg PO BID initially, increase by 100mg BID every 2-3 days to 200-400mg BID; max 2400mg/day. Hypertensive emergency (IV): 20mg IV over 2 min, then 20-80mg q10min to total 300mg; OR 1-2mg/min infusion. Preeclampsia: 200-400mg PO, then 200mg q8-12h; OR 20mg IV, then 40mg, then 80mg q10min.
- Pediatric
- Not established in children.
- Renal adjustment
- No adjustment needed (hepatically metabolized).
- Hepatic adjustment
- Reduce dose 50% in severe hepatic impairment.
- Geriatric
- Start 100mg daily; increased orthostatic hypotension risk.
- Max dose
- 2400mg/day (oral); 300mg cumulative IV (hypertensive emergency)
Pharmacokinetics
Onset
Oral: 1-2 hours; IV: 2-5 minutes
Peak effect
Oral: Tmax 1-2 hours; IV: 5-15 minutes; antihypertensive peak at 2-4 weeks
Duration
Oral: 8-12 hours; IV: 2-6 hours (dose-dependent)
Half-life
~5-8 hours (oral); ~5.5 hours (IV)
Bioavailability
~25% (extensive first-pass metabolism)
Protein binding
~50%
Metabolism
Extensive hepatic via glucuronidation (major) and CYP2C19/CYP2D6; active and inactive metabolites
Excretion
~55-60% fecal (metabolites); 5-15% renal (unchanged + metabolites)
Contraindications
- Severe bradycardia
- Second or third-degree AV block
- Sick sinus syndrome
- Cardiogenic shock
- Severe asthma or COPD
- Hypersensitivity to labetalol
Side effects
Common
Orthostatic hypotension (alpha-1 blockade)DizzinessFatigueNauseaNasal congestionEjaculatory failureTingling scalp (transient with IV)Bradycardia
Serious
- Severe hypotension / syncope
- Severe bradycardia / heart block
- Bronchospasm / asthma exacerbation
- Hepatotoxicity (rare but potentially fatal—immune-mediated hepatitis)
- Heart failure decompensation
- Jaundice
Pregnancy & lactation
Pregnancy
Preferred antihypertensive in pregnancy (with methyldopa and nifedipine). Extensive safety data in preeclampsia. May cause neonatal bradycardia and hypoglycemia if used near delivery—monitor newborn for 48-72h.
Lactation
Excreted in breast milk in low concentrations (~milk:plasma ratio 0.3-0.7); infant receives <1% of maternal dose. Compatible with breastfeeding. Monitor infant for bradycardia.
Drug interactions
Amiloride
Severe
Textbook
Hyperkalaemia more likely.
Source: KDT 7e
Sofosbuvir
Severe
Textbook
Severe bradycardia.
Extreme caution advised if amiodarone is co-administered with sofosbuvir and a beta blocker.
Source: Harrison 22e · unknown
Aminophylline
Severe
Database
Drug interaction classified as: antagonism
Source: DDInter
Arformoterol
Severe
Database
Drug interaction classified as: antagonism
Source: DDInter
Atazanavir
Severe
Database
Drug interaction classified as: synergy
Source: DDInter
Ceritinib
Severe
Database
Drug interaction classified as: synergy
Source: DDInter
Clonidine
Severe
Database
Rebound hypertension risk with abrupt withdrawal of either drug.
Withdraw labetalol first over 1-2 weeks, then taper clonidine.
Source: Kimi deep-research + Cla
Diltiazem
Severe
Database
Increased propensity for AV block, severe bradycardia, and decreased left ventricular function.
Avoid concurrent administration. The concurrent administration of diltiazem with a beta blocker is contraindicated.
Source: DDInter
Disopyramide
Severe
Database
Clinical effect not specified
Source: DDInter
Dolasetron
Severe
Database
Clinical effect not specified
Source: DDInter
Dyphylline
Severe
Database
Clinical effect not specified
Source: DDInter
Related guidelines
Ask House about Labetalol
Continue into a citation-backed clinical answer with the drug context already attached.
Sources: KD Tripathi 7e, Goodman & Gilman 14e, Katzung, BNF·Verified: 2026-05-19 · House clinical team·Cockpit curated: 2026-05-19