Postprandial Hypotension

Postprandial hypotension is a fall in systolic blood pressure of at least 20 mmHg within 2 hours of eating, or a fall to below 90 mmHg from a pre-meal level of at least 100 mmHg, with symptoms. It results from splanchnic blood pooling after a meal with inadequate compensatory vasoconstriction, and is most frequent in older adults.

• Occurs in up to a third of older people, and in patients with autonomic neuropathy (diabetes, Parkinson disease), multiple system atrophy, pure autonomic failure, chronic kidney disease on dialysis, and hypertension treated with multiple drugs.
• Peak fall usually 30 to 60 minutes after the meal and lasts up to 2 hours or more.
• Large, carbohydrate rich meals, alcohol and hot meals worsen it.
• Linked to falls, syncope, angina, stroke and increased mortality in older people.

• Dizziness, light headedness, visual blurring, weakness, fatigue and drowsiness after meals.
• Presyncope, syncope or falls, particularly after breakfast.
• Angina or transient ischaemic attack like symptoms in susceptible people.
• Symptoms worse on standing; often coexisting orthostatic hypotension.
• Examination: baseline vitals, volume status, tremor, rigidity, neuropathy, cardiac murmurs.
• Red flags: syncope with injury, chest pain, focal neurology, recurrent falls, signs of gastrointestinal bleeding.

• Measure blood pressure sitting or lying before the meal, then every 15 minutes for 2 hours after a test meal (or a 75 g oral glucose load), with a standing measurement at 30 to 60 minutes if safe.
• Home or ambulatory blood pressure monitoring with a meal diary.
• Review medicines timing and doses (antihypertensives, diuretics, nitrates, levodopa, tricyclics, alpha blockers).
• Bloods: glucose or HbA1c, urea and electrolytes, haemoglobin, thyroid function, B12.
• ECG; consider autonomic function testing if neurogenic disease is suspected.
• Differentials: orthostatic hypotension, dumping syndrome, hypoglycaemia, arrhythmia, aortic stenosis, adrenal insufficiency.

Non-pharmacological (first line)

• Eat small, frequent, low carbohydrate meals (5 to 6 per day) rather than large meals; emphasise protein, fibre and fat in moderation.
• Drink 350 to 500 mL of water 10 to 15 minutes before meals (a water bolus reduces the postprandial drop).
• Avoid alcohol with or before meals; limit hot meals.
• Remain seated or lie down for 1 to 2 hours after eating, especially after breakfast and the largest meal; avoid exertion or bathing.
• Caffeine 1 to 2 cups of coffee or tea with breakfast can attenuate the fall.
• Schedule antihypertensive and vasodilator doses away from meals, for example in the evening, and review the need for dose reduction.
• Compression stockings and abdominal binders may help.

Pharmacological (specialist; after non-drug measures)

• Acarbose 50 mg orally with the first mouthful of the main meal, titrated to 100 mg three times daily; delays glucose absorption and reduces fall. Monitor for flatulence, abdominal discomfort and liver enzymes.
• Octreotide 25 to 50 micrograms subcutaneously 30 minutes before meals (specialist only); watch for gallstones, hyperglycaemia and hypoglycaemia.
• Midodrine 2.5 to 10 mg orally 15 to 30 minutes before the main meal, avoiding late day dosing; monitor for supine hypertension.
• Caffeine 100 to 250 mg orally before meals is an alternative to coffee.

Special groups

• Diabetes: avoid hypoglycaemia; review insulin timing and sulfonylurea.
• Parkinson disease: separate levodopa from protein meals and adjust timing.
• Dialysis: adjust antihypertensive timing and ultrafiltration; avoid eating during dialysis.

Follow up and referral

• Review in 4 weeks, repeat meal blood pressure testing if symptoms persist.
• Refer for recurrent syncope, falls with injury, suspected autonomic failure or no response to measures.