Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.
Postural hypotension
Cardiology · UK scope · Sources checked 27 Aug 2026 · Clinical review pending
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Time-critical presentation
Do not attribute collapse to postural hypotension when there is exertional syncope, chest pain, new breathlessness, sustained palpitations, focal neurology, major bleeding, persistent hypotension or serious injury. These features need urgent assessment for cardiac, neurological, haemorrhagic or septic causes.
Overview
Confirm a reproducible orthostatic BP fall, identify reversible causes and use staged non-drug and drug treatment without provoking supine hypertension.
Orthostatic hypotension reflects inadequate vasoconstriction or circulating volume on standing. It is common with ageing, frailty, diabetes, Parkinsonian disorders and polypharmacy, but acute onset should prompt a search for bleeding, dehydration, infection or a new medicine.
The numerical fall must be interpreted alongside symptoms, timing and heart rate. One normal bedside test does not exclude intermittent or delayed orthostatic hypotension; repeat testing after meals, medication doses or prolonged standing can be informative.
Treatment aims to reduce syncope, falls and activity restriction rather than normalise every standing reading. Measures that raise standing BP can also raise lying BP, so the plan should specify daytime dosing, head-up sleeping where appropriate and supine-BP surveillance.
Key points
In a person with postural dizziness or falls, measure BP lying or seated and again after standing for at least 1 minute.
A fall of at least 20 mmHg systolic or 10 mmHg diastolic supports postural hypotension; symptoms can still be important when the threshold is not captured once.
Record heart-rate response and symptoms with the BP: a blunted pulse rise suggests autonomic failure, whereas marked tachycardia suggests volume loss or another orthostatic syndrome.
Aetiology
01
Reduced circulating volume
Poor intake, vomiting, diarrhoea, fever with fluid loss, bleeding or excessive diuresis reduce venous return. Standing then exposes limited preload reserve, often with compensatory tachycardia and acute symptom onset.
02
Medicine-related vasodilation or volume loss
Antihypertensives, diuretics, nitrates, alpha-blockers, dopaminergic drugs and sedating or psychoactive medicines can reduce volume, lower vascular tone or blunt protective responses, especially with polypharmacy.
03
Neurogenic autonomic failure
Parkinsonian disorders, diabetic autonomic neuropathy and other peripheral or central autonomic diseases blunt sympathetic vasoconstriction. A small heart-rate rise relative to the pressure fall, bowel or bladder dysfunction and supine hypertension support this mechanism, allowing for rate-limiting medicines.
04
Ageing, frailty and deconditioning
Impaired baroreflex sensitivity, stiff vessels, reduced muscle-pump activity and prolonged bed rest limit compensation. Heat, large meals or exercise cessation can further divert blood into dilated vascular beds.
Pathophysiology
1
Standing redistributes blood
Gravity shifts blood into leg and splanchnic veins after standing. Venous return, ventricular filling and stroke volume fall transiently, creating the physiological challenge to arterial pressure.
2
Baroreflex compensation is recruited
Reduced stretch at carotid and aortic baroreceptors normally increases sympathetic tone. Peripheral and splanchnic vasoconstriction and a faster pulse, assisted by the skeletal-muscle pump during movement, help restore venous return and pressure.
3
Compensation proves inadequate
Volume depletion, vasodilating medicines or autonomic failure can prevent sufficient vasoconstriction and cardiac response. Arterial pressure remains low, sometimes emerging after prolonged standing or a meal.
4
Cerebral perfusion falls
Inadequate pressure reduces cerebral blood flow, causing dimmed vision, cognitive slowing, presyncope or syncope. Sitting or lying reverses gravitational pooling and usually relieves symptoms quickly.
Clinical features and red flags
Typical orthostatic symptoms
Light-headedness, dimmed vision, weakness, cognitive slowing, neck/shoulder 'coat-hanger' ache, presyncope or syncope beginning after standing and improving on sitting or lying.
Significant postural BP fall
A sustained drop of at least 20 mmHg systolic or 10 mmHg diastolic after standing for at least 1 minute; document the posture, timing and symptoms.
Volume loss or drug effect
Recent vomiting/diarrhoea, fever, poor intake, bleeding, diuretic increase, vasodilator, alpha-blocker, dopaminergic or sedating medicine, alcohol or prolonged bed rest.
Autonomic failure pattern
Recurrent symptoms with a relatively small heart-rate rise, urinary or bowel dysfunction, erectile dysfunction, sweating abnormality, Parkinsonism, peripheral neuropathy or supine hypertension.
Postprandial or situational hypotension
Symptoms after a large/carbohydrate-rich meal, heat, showering, prolonged standing, exertion cessation or straining can reveal limited autonomic reserve.
Investigations
01Lying-to-standing BP and pulseFirst step
Why
Demonstrate the haemodynamic change and relate it to symptoms.
Interpretation and limitations
Rest supine when feasible, record baseline, then BP/pulse after standing for at least 1 minute; repeat at about 3 minutes or longer if delayed symptoms are suspected. A fall of at least 20/10 mmHg is significant.
0212-lead ECG
Why
Look for bradyarrhythmia, conduction disease, pre-excitation, long QT or ischaemic clues that change the syncope pathway.
Interpretation and limitations
An abnormal ECG or exertional/supine syncope merits urgent or specialist cardiac assessment rather than a purely orthostatic label.
03FBC, U&E/eGFR and glucose
Why
Identify anaemia/bleeding, dehydration, electrolyte disturbance, renal impairment or dysglycaemia.
Interpretation and limitations
Select additional CRP, cultures, thyroid, B12 or cortisol testing from the history; do not order a broad panel without a clinical question.
04Medication, fluid and falls review
Why
Find reversible exposures and quantify harm.
Interpretation and limitations
Relate symptom timing to doses and meals; include over-the-counter sedatives, alcohol and medications with anticholinergic or vasodilator effects.
05
Differential diagnosis
01
Vasovagal syncope
Pain, emotion or prolonged standing with warmth, sweating and nausea suggests a reflex faint. Episodes are trigger-linked rather than consistently accompanied by a reproducible postural pressure fall.
02
Cardiac arrhythmia
Abrupt collapse without a postural relationship, preceding palpitations or an abnormal ECG raises arrhythmic concern. Rhythm monitoring should match event frequency rather than assuming dizziness is orthostatic.
03
Structural outflow obstruction
Syncope during exertion, a cardiac murmur or known valve or myocardial disease suggests aortic stenosis or hypertrophic cardiomyopathy. These features require cardiac assessment, including imaging as indicated, rather than repeated postural measurements alone.
04
Postural orthostatic tachycardia syndrome
Chronic orthostatic intolerance with a prominent sustained pulse rise but without the characteristic pressure fall suggests a tachycardia syndrome. Medicines, dehydration and other causes still require exclusion.
05
Vestibular dizziness
A spinning sensation, nystagmus or symptoms triggered by head movement rather than standing suggest vertigo. Blood pressure usually remains stable during a typical episode, helping separate vestibular from circulatory symptoms.
Additional chapter-specific clues
Alternative dangerous causeRed flag
Exertional or supine syncope, chest pain, abrupt dyspnoea, persistent palpitations, melaena/haematemesis, focal neurology, sepsis features or family history of sudden death.
Management
01confirmSymptoms on standingFirst stepDizziness, presyncope, syncope or unexplained falls related to posture.+
1First: assess ABCs, injury, bleeding, infection, neurological deficit and cardiac red flags; use the urgent pathway if present.
2Next: record lying or seated BP/pulse and repeat after standing for at least 1 minute, documenting symptoms and considering a 3-minute reading.
3Next: obtain an ECG and targeted blood tests, then review volume status, meals, alcohol and every prescribed/non-prescribed medicine.
4EscalationEscalation: recurrent unexplained syncope, abnormal ECG, severe persistent hypotension or a possible autonomic disorder needs specialist assessment.
02reversibleTreat the causeA postural fall is confirmed or strongly suspected.+
1
Complications
01
Falls and traumatic injury
Presyncope or loss of consciousness while upright can cause fractures, head injury and soft-tissue trauma. Frailty, anticoagulation and limited warning increase the consequences of each episode.
02
Functional decline
Fear of standing and recurrent symptoms reduce walking and self-care. Resulting deconditioning weakens the skeletal-muscle pump, worsening venous pooling and creating a cycle of greater dependence.
03
Cardiac, cerebral or renal ischaemia
Prolonged or recurrent hypotension can aggravate angina, cognitive symptoms or kidney injury in people with limited vascular reserve, making functional symptoms and organ markers important treatment outcomes.
04
Supine hypertension
Autonomic failure may produce high lying pressure despite low standing pressure, and pressor treatment can worsen it. This limits therapy and may increase nocturnal cardiovascular and renal stress.
Monitoring and follow-up
Track symptom frequency, syncope/falls, standing time and daily function rather than treating the BP number alone.
Repeat lying and standing BP/pulse after causal medication changes and after every pressor titration.
Check for supine or nocturnal hypertension, especially in autonomic failure and during midodrine/fludrocortisone treatment.
With fludrocortisone, monitor weight, oedema, potassium, sodium and renal function; ask about breathlessness and orthopnoea.
With midodrine, review pulse, urinary flow/retention, scalp tingling/piloerection and the timing of the final dose.
Reassess the need for falls support, mobility aids, driving advice and specialist syncope/autonomic review after any recurrence.
Special situations
Use standing BP for the hypertension target
NICE advises this when a significant postural fall or symptoms are present, reducing the risk of overtreating the seated value.
Heart rate adds mechanism
A substantial pulse rise supports hypovolaemia or compensatory physiology; a disproportionately small rise raises neurogenic autonomic failure, though medicines such as beta-blockers confound it.
Supine hypertension can coexist
Autonomic failure can produce low standing BP and high nocturnal BP, making ABPM and daytime-only pressor dosing valuable.
Compression must reach the capacitance bed
Abdominal or waist-high compression generally addresses splanchnic and venous pooling better than short stockings.
A normal one-minute test is not the end
Repeat after three minutes, after a provoking meal/medicine or with specialist beat-to-beat testing when the history remains convincing.
Deprescribing is a balance
Stopping all antihypertensives can increase stroke or heart-failure risk; adjust the most culpable agent and timing while measuring standing response.
Common pitfalls
01
Calling every fall 'postural' without ECG, red-flag and injury assessment.
02
Measuring only seated BP or failing to record symptoms and pulse after standing.
03
Advising unrestricted salt or fluid in heart failure, CKD, oedema or severe supine hypertension.
04
Giving midodrine at bedtime or titrating without supine-BP and urinary-retention checks.
05
Escalating pressor drugs before correcting dehydration, bleeding or contributory medicines.
Practice
Two practice questions
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Question 1 of 2
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CardiologyOriginal SBA
Diagnostic BP change
A patient becomes light-headed on standing. BP falls from 148/82 mmHg lying to 126/72 mmHg after 1 minute. Which interpretation is most accurate?
Sources and review status3 sources · checked 27 Aug 2026 · clinical review pending+
Sources
Sources and review status
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.
First address dehydration, blood loss, infection, deconditioning and contributory medicines such as antihypertensives, diuretics, nitrates, alpha-blockers and psychoactive drugs.
For coexisting hypertension, NICE advises basing the treatment target on standing BP when there is a significant postural fall or postural symptoms.
Individualised fluids, salt where safe, gradual position change, physical counter-pressure manoeuvres and abdominal or waist-high compression are core measures.
Midodrine is licensed for severe orthostatic hypotension due to autonomic dysfunction after correctable factors have been excluded; avoid dosing near bedtime.
Every pressor strategy can worsen supine hypertension, urinary retention or fluid overload, so benefit must be demonstrated with standing function as well as BP readings.
Ambulatory BP monitoring
Why
Assess daytime falls, nocturnal/supine hypertension and the effect of medication timing.
Interpretation and limitations
Useful in autonomic failure or when treating coexisting hypertension; nocturnal hypertension may limit pressor therapy.
06Specialist autonomic or syncope testing
Why
Clarify recurrent unexplained episodes, delayed orthostatic hypotension or autonomic failure.
Interpretation and limitations
Tilt testing, beat-to-beat BP, autonomic reflex testing or rhythm monitoring should follow the suspected mechanism rather than replace a careful bedside assessment.
First: correct dehydration, infection, blood loss, anaemia or electrolyte disturbance and mobilise safely after bed rest.
2Next: rationalise contributory medicines one at a time, balancing heart failure, angina, arrhythmia and hypertension indications.
3Next: when hypertension coexists, use standing BP to guide the target and adjust dose timing rather than abandoning cardiovascular protection indiscriminately.
4EscalationEscalation: arrange urgent evaluation if hypotension persists despite initial correction or is accompanied by AKI, bleeding or systemic illness.
03non-drugBuild orthostatic tolerancePersistent symptoms after immediate reversible factors are addressed.+
1First: teach slow staged rising, sitting immediately with warning symptoms and physical counter-pressure manoeuvres such as leg crossing and muscle tensing.
2Next: encourage adequate fluid intake and consider additional dietary salt only if heart failure, CKD, oedema and supine hypertension do not make it unsafe.
3Next: use smaller meals, limit excess alcohol/heat and consider an abdominal binder or waist-high compression; knee-length stockings alone are often insufficient.
4EscalationEscalation: refer for falls, physiotherapy or autonomic review when symptoms still restrict activity or cause injury.
04pressorPersistent severe neurogenic symptomsFunction-limiting orthostatic hypotension due to autonomic dysfunction despite correction and non-drug measures.+
1First: document supine and standing BP, urinary symptoms, renal function and the functional goal before drug treatment.
2Next: under experienced supervision start midodrine 2.5 mg three times daily during waking hours and titrate no more often than weekly; keep the last dose at least 4 hours before bed.
3Next: reassess symptoms, standing function, supine BP, pulse and urinary retention after each change; stop if there is no worthwhile benefit.
4EscalationEscalation: specialist services may consider off-labelfludrocortisone when volume expansion is appropriate, with close BP, weight, potassium and heart-failure monitoring.
Key medicines and prescribing safety2 treatments · regimens, roles and cautions+
Licensed treatment for severe orthostatic hypotension due to autonomic dysfunction when correctable factors have been excluded and other measures are inadequate.
Midodrine
2.5 mg orally three times daily initially during waking hours; increase at weekly intervals according to response up to 10 mg three times daily. Take the final dose at least 4 hours before bedtime.
Monitor lying and standing BP. Stop/review for severe supine hypertension, bradycardia or urinary retention. Contraindications include severe organic heart disease (including aortic aneurysm), hypertension, acute kidney disease or CrCl <30 mL/min, serious obliterative vascular disease, serious prostate disorder/urinary retention, phaeochromocytoma, hyperthyroidism and narrow-angle glaucoma; check the current SmPC for the full list and interactions.
Specialist option to expand plasma volume when non-drug treatment is inadequate and volume expansion is safe.
Fludrocortisone (off-label)
100 micrograms orally once daily is the adult regimen used in the placebo-controlled evidence summarised by NICE; any titration should be specialist-directed.
Unlicensed for postural hypotension in the UK, and NICE found the evidence base limited. Can cause supine hypertension, oedema, heart-failure decompensation, hypokalaemia and headache; monitor BP, weight, electrolytes and renal function and avoid or use extreme caution in heart failure/CKD.