183 - Orthostatic hypotension

Orthostatic hypotension

182 The Maudsley® Prescribing Guidelines in Psychiatry CHAPTER 1 Blood pressure changes with antipsychotics Orthostatic hypotension Orthostatic hypotension (postural hypotension) is one of the most common cardiovascular adverse effects of antipsychotics and some antidepressants. Orthostatic hypotension generally presents acutely, during the initial dose titration period, but it can also be a chronic problem.1 Symptoms include dizziness, light-­headedness, asthenia, headache and visual disturbance. Patients may not be able to communicate the severity of these symptoms effectively and subjective reports of postural dizziness correlate only weakly with the magnitude of measured postural hypotension.2 Blood pressure monitoring is recommended in suspected cases to confirm orthostatic hypotension (usually defined as a ≥20mmHg fall in systolic blood pressure and/or a ≥10mmHg fall in diastolic blood pressure within 3 minutes of standing).3 Orthostatic hypotension impairs quality of life and is associated with an increased risk of falls, cardiovascular disease, depression and death.3 Risk factors are shown in Table 1.40. Slow dose titration is a commonly used and often effective strategy to avoid or minimise orthostatic hypotension. However, in some cases orthostasis may be a dose-­limiting side effect, preventing optimal treatment. Potential management strategies are shown in Table 1.41. Table 1.40  Risk factors for orthostatic hypotension.2 Treatment factors ■ ■IM administration route (peak levels higher and achieved more rapidly) ■ ■Rapid dose increases ■ ■Antipsychotic polypharmacy ■ ■Drug interactions (e.g. tricyclic antidepressants, antihypertensive drugs – particularly alpha blockers, beta blockers and diuretics, although the number of antihypertensive drugs prescribed may be more predictive than the class)3 Patient factors ■ ■Old age (young patients may have sinus tachycardia with minimal change in blood pressure) ■ ■Disease states associated with autonomic dysfunction (e.g. Parkinson’s disease) ■ ■Dehydration ■ ■Cardiovascular disease Table 1.41  Management of antipsychotic-­induced orthostatic hypotension.2,4 Minimise the risk of treatment ■ ■Limit initial doses and titrate slowly according to tolerability (most people develop a tolerance to the hypotensive effect) ■ ■Consider a temporary dose reduction if hypotension develops ■ ■Reduce peak plasma levels by using smaller and more frequent dosing or by using modified-­release preparations Non-pharmacological therapies ■ ■Advice to patients (e.g. sitting on the edge of the bed for several minutes before attempting to stand in the morning and slowly rising from a seated position) ■ ■Abdominal binders and compression stockings can be used ■ ■Increasing fluid intake to 1.25–2.5L/day is advisable for all patients who are not fluid restricted (Continued)