Management - Orthostatic Hypotension
Stop causative or contributory drug
- drug-induced orthostatic hypotension is common and usually resolves once the drug is ceased
- an alternative drug should be used for the original indication whenever possible.
Education
- stand up slowly and in stages (i.e. if lying down, first sit up, then stand up, waiting for any symptoms to subside at each stage).
Fluid
- ensure an adequate fluid intake for age, height and weight.
Salt
- Avoid a low salt diet. Additional dietary salt will boost the plasma volume. Salt can be consumed by adding salt to their food, consuming salty or processed foods. They should aim to have at least 150mmol (3500 mg) of sodium per day.
Physical counter-manoevres
- Crossing one leg over the other at thigh level and then squeezing the legs together rapidly and substantially increases blood pressure
- Squatting or putting your head down below your waist is also effective (but the person needs to be careful when they stand up again).
- Exercises to strengthen abdominal and leg muscles, such as swimming, provide additional benefit.
Waist high compression stockings
- These cause compression in the legs, buttocks and abdominal veins, which limits the gravitational displacement of blood into the venous system on standing.
- However compression stockings providing 30mmHg at the ankle need to be used and they need to be waist high as most of the venous volume is in the buttock and thigh muscles.
- Waist high, firm compression stockings are expensive, hot and difficult to put on, so they are only an option for young, motivated people with severe orthostatic hypotension.
Raise the head of the bed
- Raising the head of the bed 20-25cm improves orthostatic hypotension, possibly by decreasing nocturnal renal arterial pressure and renin secretion or by producing ankle oedema which lessens venous pooling with standing.
Medications
Medications may be needed if the orthostatic hypotension does not improve with the simple measures mentioned above.
Fludrocortisone
- Fludocortisone is a mineralocorticoid. Dose 0.1-0.2mg/day
- It expands intravascular volume by increasing salt and water retention by the kidney and sensitises receptors which cause vasoconstriction.
- Side effects include heart failure, hypokalaemia and nocturnal hypertension.
Midodrine
- Midodrine is an a- adrenoreceptor agonist and causes peripheral vasoconstriction. Dose 2.5-10mg tds
- It is short acting, so it may need to be taken up to three times day during daytime hours
- Side effects include supone hypertension, piloerection and urinary retention.
- It is only availablein Australia via the Therapeutic Goods Administration Special Access Scheme
Erythropoietin
- Erythropoietin has been successfully used for management of orthostatic hypotension in autonomic dysfunction.
- It acts as a vasoconstrictor and also improves the anaemia which is common in autonomic dysfunction.
Short-acting Nocturnal Antihypertensives
These may be required in combination with pressor agents if symptomatic orthostatic hypotension and nocturnal supine hypertension coexist - particularly in the setting of Autonomic Failure.
Short acting antihypertensives used for this indication include :
- Captopril
- Hydralazine and
- Clonidine
These medications can also lessen the nocturnal diuresis which occurs as a result of the supine hypertension which in turn lessens morning orthostatic hypotension.
