Hypotension postural/orthostatic

Most cardiovascular reflexes remain intact after administration of methyldopa, and blood pressure reduction is not markedly dependent on posture. Postural (orthostatic) hypotension sometimes occurs, particularly in volume-depleted patients. One potential advantage of... 

The most typical side effect is dizziness when you stand up from a sitting or lying position, caused by a drop in blood pressure. This is termed postural hypotension or orthostatic hypotension. Adjusting the dosage may help. 

Postural (orthostatic) hypotension A drop in blood pressure that occurs after sitting or standing suddenly and resulting in faintness and dizziness. 

The major adverse effect is postural (orthostatic) hypotension, due to the increase in venous capacitance. As a,-receptor antagonists block receptors on both arteries and veins, both vasodilatation and a decrease in venoconstriction are seen. This results in an increase in venous capacitance. As gravity draws blood into the veins upon standing, the compensatory venoconstrictor mechanisms are blocked by the drug, resulting in pooling of blood in the extremities. 

Extrapyramidal symptoms, akathisia, dystonia, tardive dyskinesia, drowsiness, headache, dry mouth, orthostatic hypotension Agitation, dizziness, nervousness, akathisia, constipation, fever, weight gain Hypotension, postural hypotension, tardive dyskinesia, photophobia, urticaria, nasal congestion, dry mouth, akathisia, dystonia, pseudo parkin son ism, behavioral changes, headache, photosensitivity Parkinson-like symptoms, motor restlessness, dystonia, oculogyric aisis, tardive dyskinesia, dry mouth, diarrhea, headache, rash, drowsiness... 

Alpha la adrenergic receptor antagonist Dizziness Elushing Impotence Nasal congestion Postural (orthostatic) hypotension Tachycardia Weakness... 

Discuss ways to promote an optimal response to therapy, how to manage common adverse reactions, nursing actions that may be taken to minimize orthostatic or postural hypotension, and important points to keep in mind when educating patients about the use of adrenergic blocking drugs. 

Symptoms of postural or orthostatic hypotension often lessen with time, and tire patient may be allowed to get out of bed or chair slowly without assistance The nurse must exercise good judgment in this matter. Allowing tire patient to rise from a lying or sitting position without help is done only when tire determination has been made that tire symptoms have lessened and ambulation poses no danger of falling. 

No evidence of injury related to orthostatic or postural hypotension is seen. 

When any antihypertensive drug is given, postural or orthostatic hypotension may be seen in some patients, especially early in therapy. Postural hypotension is the occurrence of dizziness and light-headedness when the individual rises suddenly from a lying or sitting position. Orthostatic hypotension occurs when the... 

Risk for Injury related to dizziness or light-headedness secondary to postural or orthostatic hypotensive episodes... 

Electrolyte imbalances, anorexia, nausea, vomiting, dizziness, rash, photosensitivity reactions, postural or orthostatic hypotension, glycosuria Electrolyte imbalances, anorexia, nausea, vomiting, fever, chills, anxiety, confusion, hematologic changes me as bumetanide... 

Anorexia and vomiting Postural faintness, orthostatic hypotension... 

The treatment of elderly patients with hypertension, as well as those with isolated systolic hypertension, should follow the same approach as with other populations with the exception that lower starting doses may be warranted to avoid symptoms and with special attention paid to postural hypotension. This should include a careful assessment of orthostatic symptoms, measurement of blood pressure in the upright position, and caution to avoid volume depletion and rapid titration of antihypertensive therapy.2 In individuals with isolated systolic hypertension, the optimal level of diastolic pressure is not known, and although treated patients who achieve diastolic pressures less than 60 to 70 mm Hg had poorer outcomes in a landmark trial, their cardiovascular event rate was still lower than those receiving placebo.69... 

The vasodilators decrease total peripheral resistance and thus correct the hemodynamic abnormality that is responsible for the elevated blood pressure in primary hypertension. In addition, because they act directly on vascular smooth muscle, the vasodilators are effective in lowering blood pressure, regardless of the etiology of the hypertension. Unlike many other antihypertensive agents, the vasodilators do not inhibit the activity of the sympathetic nervous system therefore, orthostatic hypotension and impotence are not problems. Additionally, most vasodilators relax arterial smooth muscle to a greater extent than venous smooth muscle, thereby further minimizing postural hypotension. 

Blood vessels receive chiefly vasoconstrictor fibers from the sympathetic nervous system therefore, ganglionic blockade causes a marked decrease in arteriolar and venomotor tone. The blood pressure may fall precipitously because both peripheral vascular resistance and venous return are decreased (see Figure 6-7). Hypotension is especially marked in the upright position (orthostatic or postural hypotension), because postural reflexes that normally prevent venous pooling are blocked. 

Orthostatic hypotension is occasionally a problem with the aforementioned drugs, and dizziness and syncope sometimes occur after a sudden change in posture. Some patients also experience gasnointestinal disturbances including nausea, vomiting, and diarrhea. Peripheral edema as evidenced by swelling in the feet and legs has also been reported. 

At presentation, the patient was hemodynami-cally unstable. She had a rapid heart rate and exhibited orthostatic hypotension (a fall in blood pressure on assuming an upright posture) and slow mentation. Her fluid deficit was greater than 4 L. Her lab work revealed hyponatremia (low serum sodium), hyperkalemia (high serum potassium), and a severe anion gap metabolic acidosis with dehydration. Her anion gap was 28, and her corrected serum Na+ was 135 mEq/L. 

A significant increase in postural hypotension with respect to the control would indicate that the test compound may produce orthostatic hypotension in human. Moreover, some compounds, like sympathomimetics, can reduce or prevent postural hypotension. 

Prazosin is an a i-selective adrenoceptor antagonist which causes vasodilation and a fall in BP. Alpha-adrenoceptor antagonists also have a favourable effect on blood lipids and are useful for people with raised cholesterol. However, orthostatic hypotension may occur during treatment because prazosin interferes with the postural reflexes, which are triggered when a patient stands up from a supine or sitting position. 

Postural hypotension is particularly hazardous in susceptible patients, such as the elderly and those with depleted intravascular volume or reduced cardiovascular output. The risk of orthostatic hypotension is markedly increased after parenteral administration. The combination of alpha-adrenoceptor blockade and sedative effects may explain the increased risk of falling when taking neuroleptic drugs (SEDA-12, 52). 

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