Preventing and treating orthostatic hypotension: As easy as A, B, C
ABSTRACTOrthostatic hypotension is a chronic, debilitating illness that is difficult to treat. The therapeutic goal is to improve postural symptoms, standing time, and function rather than to achieve upright normotension, which can lead to supine hypertension. Drug therapy alone is never adequate. Because orthostatic stress varies with circumstances during the day, a patient-oriented approach that emphasizes education and nonpharmacologic strategies is critical. We provide easy-to-remember management recommendations, using a combination of drug and nondrug treatments that have proven efficacious.
KEY POINTS
- Treatment is directed at increasing blood volume, decreasing venous pooling, and increasing vasoconstriction while minimizing supine hypertension.
- Patient education and nondrug strategies alone can be effective in mild cases. Examples: consuming extra fluids and salt, wearing an abdominal binder, drinking boluses of water, raising the head of the bed, and performing countermaneuvers and physical activity.
- Moderate and severe cases require additional drug treatment. Pyridostigmine (Mestinon) is helpful in moderate cases. Fludrocortisone (Florinef) and midodrine (ProAmatine) are indicated in more severe cases.
B: Boluses of water
Rapidly drinking two 8-oz (500-mL) glasses of cold water helps expand plasma volume. It also, within a few minutes, elicits a significant pressor effect that is in part norepinephrine-mediated,18,19 increasing the standing systolic blood pressure by more than 20 mm Hg for about 2 hours and improving symptoms and orthostatic endurance.18,20 This easy technique can be used when prolonged standing is expected (eg, shopping).
B (continued): Bed up
The head of the bed of a patient with orthostatic hypotension should be elevated by 10 to 20 degrees or 4 inches (10 cm) to decrease nocturnal hypertension and nocturnal diuresis.21 During the day, adequate orthostatic stress, ie, upright activity, should be maintained. If patients are repeatedly tilted up, their orthostatic hypotension is gradually attenuated, presumably by increasing venomotor tone.22
C: Countermaneuvers
Physical countermaneuvers involve isometrically contracting the muscles below the waist for about 30 seconds at a time, which reduces venous capacitance, increases total peripheral resistance, and augments venous return to the heart.23,24 These countermeasures can help maintain blood pressure during daily activities and should be considered at the first symptoms of orthostatic intolerance and in situations of orthostatic stress (eg, standing for prolonged periods).
Specific techniques include23:
- Toe-raising
- Leg-crossing and contraction
- Thigh muscle co-contraction
- Bending at the waist
- Slow marching in place
- Leg elevation.
D: Drugs
Midodrine, a vasopressor, is effective and safe when used for treating neurogenic orthostatic hypotension.25 It has been shown to increase standing systolic blood pressure, reduce orthostatic lightheadedness, and increase standing and walking time.
A common starting dose is 5 mg three times a day; most patients respond best to 10 mg three times a day. As its duration of action is short (2 to 4 hours),25–27 it should be taken before arising in the morning, before lunch, and in the midafternoon. To avoid nocturnal supine hypertension, doses should not be taken after the midafternoon, and a dose should be omitted if the supine or sitting blood pressure is greater than 180/100 mm Hg.
Midodrine’s main side effects are supine hypertension, scalp paresthesias, and pilomotor reactions (goosebumps). Vasoconstrictors such as midodrine are ineffective when plasma volume is reduced.
Fludrocortisone is a synthetic mineralocorticoid that has a pressor effect as a result of its ability to expand plasma volume and increase vascular alpha-adrenoceptor sensitivity.28–30 This medication is helpful when plasma volume fails to adequately increase with salt supplementation31 and for patients who cannot ingest enough salt or do not respond adequately to midodrine.
The usual dose is 0.1 to 0.2 mg/day, but it may be increased to 0.4 to 0.6 mg/day in patients with refractory orthostatic hypotension.
If the patient gains 3 to 5 pounds (1.2–2.3 kg) and develops mild dependent edema, you can infer that the plasma volume has expanded adequately. However, in view of these effects, fludrocortisone is contraindicated in congestive heart failure and chronic renal failure. The potential risks are severe hypokalemia and excessive supine hypertension. Frequent monitoring of serum potassium, a diet high in potassium, and regular checks of supine blood pressure are advised, especially at higher doses, when added to midodrine, or in elderly patients who tend to poorly tolerate the medication.28,29,32
Pyridostigmine is a cholinesterase inhibitor that improves ganglionic neurotransmission in the sympathetic baroreflex pathway. Because this pathway is activated primarily during standing, this drug improves orthostatic hypotension and total peripheral resistance without aggravating supine hypertension. Because the pressor effect is modest, it is most adequate for patients with mild to moderate orthostatic hypotension.33,34
Dosing is started at 30 mg two to three times a day and is gradually increased to 60 mg three times a day. The drug’s effectiveness can be enhanced by combining each dose of pyridostigmine with 5 mg of midodrine without occurrence of supine hypertension.34 Mestinon Timespan, a 180-mg slow-release pyridostigmine tablet, can be taken once a day and may be a convenient alternative.
The main side effects are cholinergic (abdominal colic, diarrhea).
Review the patient’s medications. If he or she is taking any drug that may cause orthostatic hypotension, consider discontinuing it, substituting another drug, or changing the dosage (Table 2). In the elderly, antiparkinsonian, nitrate, antidepressant, diuretic, prostate, and antihypertensive medications35 may be particularly suspect.
E: Education
Education is probably the single most important factor in the proper control of orthostatic hypotension. A number of issues should be considered.
- Patients should be taught, in simple terms, the mechanisms that maintain postural normotension and how to recognize the onset of orthostatic symptoms.
- They must realize that there is no specific treatment of the underlying cause and that drug treatment alone is not adequate.
- They should be taught nonpharmacologic approaches and be aware that other drugs they start may worsen symptoms.
It is also important that the patient learn the conditions (and their mechanisms) that can lower blood pressure (Table 3). Such conditions include prolonged or motionless standing, alcohol ingestion (causing vasodilation), carbohydrate-heavy meals (causing postprandial orthostatic hypotension related to an increase in the splanchnic-mesenteric venous capacitance), early morning orthostatic hypotension related to nocturnal diuresis and arising from bed, physical activity sufficient to cause muscle vasodilation, heat exposure (eg, hot weather or a hot bath or shower) producing skin vessel vasodilation, sudden postural changes, and prolonged recumbency. Once these stressors are explained, patients have no difficulty recognizing them.
The patient should also be instructed in how to manage situations of increased orthostatic stress and periods of orthostatic decompensation, to minimize nocturnal hypertension, and to modify their activities of daily living. Keeping a log of supine and upright blood pressures (taken with an automated sphygmomanometer) during situations of orthostatic stress can help establish whether worsening symptoms are related to orthostatic hypotension or to another mechanism. Once patients discover that they can actively deal with these situations, they develop a great sense of empowerment.
E (continued): Exercise
Mild physical exercise improves orthostatic tolerance by reducing venous pooling and increasing plasma volume.36 Deconditioning from lack of exercise exacerbates orthostatic hypotension.37 Because upright exercise may increase the orthostatic drop in blood pressure, training in a supine or sitting position (eg, swimming, recumbent biking) is advisable. Isotonic exercise (eg, light weight-lifting) is recommended because the incorrect straining and breath-holding during isometric exercise (eg, holding weights in the same position) may decrease venous return.
