/publications/issue/2008/2008-12/2008-12-9953

2-Minute Consultation: Hypotension Calls for Aggressive Monitoring

Author: Guido Zanni, PhD

Dr. Zanni is a health systems consultant and psychologist based in Alexandria, Virginia.

Up to 30% of individuals are hypotensive1,2 with elders disproportionately affected.3 Because hypotension is associated with Parkinson's disease, stroke, transient ischemic attacks, myocardial infarction, electrocardiogram abnormalities, and Alzheimer's disease, these patients may ask about hypotensive symptoms.4-6

To diagnose hypotension, clinicians record blood pressure (BP) every minute for 5 minutes after patients have lain down for 15 minutes and then stand. If systolic BP falls more than 20 mm Hg, or diastolic BP falls more than 10 mm Hg, hypotension is present.4

Orthostatic hypotension (OH) develops when systems fail to compensate for the approximately 500-mL decrease in blood routed to the heart as a person stands, and blood pools in the extremities. 6 Up to 50% of OH is drug-induced.7 Hypovolemia induced by excessive diuretic use is the most common cause of OH.7 Patients' drug regimens should be screened for antihypertensives, monoamine oxidase inhibitors, tricyclic antidepressants, antianginals, levodopa, dopamine, selegiline, barbiturates, and alcohol. 4,7,8

Postprandial hypotension (PPH) is observed only in elders9,10 and may cause syncope, falls, dizziness, fatigue, angina pectoris, stroke, and myocardial infarction.11 PPH is most likely to occur after breakfast.12,13

Pharmacists should be prepared to discuss both pharmacologic (Table 1) and nonpharmacologic (Table 2) interventions that achieve adequate functional capacity (and not necessarily a specific BP reading).8 As with hypertension, clinicians must aggressively monitor hypotension.

Table 1
Pharmacologic Hypotension Treatments

Fludrocortisone: 0.1-0.4 mg daily for at least 2 weeks stimulates renal sodium retention; sodium supplementation may be needed. Side effects include weight gain of up to 8 lb, hypokalemia, hypomagnesemia, and supine hypertension. Monitor warfarin interactions.

Midodrine: to prevent peripheral resistance and venous pooling in neurogenic and dialysisrelated hypotension, 2.5 mg with breakfast and lunch, increasing by 2.5 mg 3 times daily every 2 days, to a maximum of 30 mg daily will elevate standing systolic BP 15 to 30 mm Hg within 1 hour for up to 3 hours. Administer doses during the day while the patient is active. Adverse effects include pilomotor reactions, paresthesia, pruritus (especially the scalp), distrait (hesitancy and retention), and chills. To avoid supine hypertension, schedule the last dose of the day before 6 pm or 4 hours before bedtime. It interacts with digoxin, calcium channel blockers, and beta-blockers, and is contraindicated with alpha-adrenergic receptor stimulators. It may antagonize the alpha-adrenergic blockers.

Erythropoietin: although unapproved for hypotension, increases red blood cell volume, and sometimes corrects OH. Include concurrent iron supplementation to prevent iron deficiency anemia.

Octreotide: a somatostatin analogue, decreases splanchnic blood flow and increases BP. In PPH, initial doses of 50 ?g subcutaneously are used 30 minutes before meals for 2 weeks. If response occurs, a monthly depot injection can be used. Octreotide can alter dietary fat absorption, and depress B12 levels.

BP = blood pressure; OH = orthostatic hypotension; PPH = postprandial hypotension.
Adapted from references 4,8,9,12.


Table 2
Nonpharmacologic Hypotension Treatments

Eat small, frequent, low-carbohydrate meals early in the day and consume larger meals late in the day, when BP tends to be higher.

Exercise before meals to improve vascular tone and reduce venous pooling.

Use muscle tensing. When hypotension begins, crossing legs can increase BP by 13 mm Hg, or squatting can increase BP 44 mm Hg.

Increase sodium intake 5-10 g above recommended dietary levels.

Increase fluid intake. Consuming 480 mL of water can increase seated BP 11 mm Hg in healthy elders and 43 mm Hg in elders with autonomic failure. Response occurs within 5 minutes, peaking 25 minutes later.

Use elastic stockings.

Avoid alcohol.

Elevate the head of the bed approximately 20o (about 8 inches).

Avoid abrupt positional changes and long periods of inactivity.

Although controversial, some clinicians recommend 2 cups of coffee in the morning (caffeine is a phosphodiesterase inhibitor). Caffeinated beverages should be consumed before meals rather than with meals.

BP = blood pressure.
Adapted from references 4,8,12-15.


References

  1. Harris T, Lipsitz LA, Kleinman JC, Cornoni-Huntley J. Postural change in blood pressure associated with age and systolic blood pressure: The National Health and Nutrition Examination Survey II. J Gerontol. 1991;46(5):M159-M163.
  2. Tilvis RS, Hakala SM, Valvanne J, Erkinjuntti T. Postural hypotension and dizziness in a general aged population: a four-year follow-up of the Helsinki aging study. J Am Geriatri Soc. 1996;44(7):809-814.
  3. Montastruc JL, Laborie I, Bagheri H, Senard JM. Drug-induced orthostatic hypotension: a five-year experience in a regional pharmacovigilance centre in France. Clin Drug Invest. 1997;14(1):61-65.
  4. Senard JM, Brefel-Courbon C, Rascol O, Montastruc JL. Orthostatic hypotension in patients with Parkinson's disease: pathophysiology and management. Drugs Aging. 2001;18(7):495-505.
  5. Qiu C, von Strauss E, Fastbom J, Winblad B, Fratiglioni L. Low blood pressure and risk of dementia in the Kungsholmen project: a 6-year follow-up study. Arch Neurol. 2003;60(2):223-228.
  6. Luukinen H, Koski K, Laippala P, Kivela SL. Prognosis of diastolic and systolic orthostatic hypotension in older persons. Arch Intern Med. 1999;159(3):273-280.
  7. Cardiovascular Disorders: Orthostatic hypotension and syncope. The Merck Manual of Diagnosis and Therapy [online edition]. www.merck.com/mmpe/sec07/ch069/ch069d.html#sec07-ch069-ch069d-10. Accessed October 24, 2008.
  8. Frishman WH, Azer V, Sica D. Drug treatment of orthostatic hypotension and vasovagal syncope. Heart Dis. 2003;5(1):49-64.
  9. Cruz DN. Midodrine: a selective alpha-adrenergic agonist for orthostatic hypotension and dialysis hypotension. Expert Opin Pharmacother. 2000;1(4):835-840.
  10. Lipsitz LA, Nyquist RP Jr, Wei JY, Rowe JW. Postprandial reduction in blood pressure in the elderly. N Engl J Med. 1983;309(2):81-83.
  11. Bou-Holaigah I, Rowe PC, Kan J, Calkins H. The relationship between neurally mediated hypotension and the chronic fatigue syndrome. JAMA. 1995(12);274:961-967.
  12. O'Mara G, Lyons D. Postprandial hypotension. Clin Geriatr Med. 2002;18(2):307-321.
  13. Morley J. Editorial: Postprandial hypotension-the ultimate Big Mac attack. J Gerontol A Biol Sci Med Sci. 2001;56(12):M741-M743.
  14. Jordan J, Shannon JR, Black BK, et al. The pressor response to water drinking in humans: a sympathetic reflex? Circulation. 2000;101(5):504-509.
  15. Zoler ML. Water consumption can boost low blood pressure. Fam Prac News. 2001;31(3):11.