Can prochlorperazine (antiemetic medication) cause hypotension (low blood pressure)?

Prochlorperazine Can Cause Hypotension

Yes, prochlorperazine can cause hypotension (low blood pressure), which is listed as a significant adverse effect in drug labeling and clinical guidelines.

Mechanism and Risk

• Prochlorperazine, a phenothiazine antiemetic, can cause hypotension through its alpha-adrenergic blocking properties 1, 2
• The FDA drug label specifically warns about hypotension as a potential adverse effect, recommending caution in patients with impaired cardiovascular systems 1
• Phenothiazines like prochlorperazine can produce alpha-adrenergic blockade, which directly affects blood pressure regulation 3

Clinical Significance

• The hypotensive effect can be significant enough that the FDA recommends keeping patients lying down and observing them for at least 30 minutes after parenteral administration 1
• If hypotension occurs after oral or parenteral dosing, patients should be placed in a head-low position with legs raised 1
• In cases of severe hypotension, vasoconstrictors may be required, with LEVOPHED and NEO-SYNEPHRINE being suitable options 1

Special Considerations

• Hypotension risk may be increased when prochlorperazine is combined with other medications:
  • Thiazide diuretics may accentuate the orthostatic hypotension that occurs with phenothiazines 1
  • Antihypertensive effects of guanethidine and related compounds may be counteracted when used concomitantly with phenothiazines 1
  • Concomitant administration with beta-blockers like propranolol results in increased plasma levels of both drugs, potentially enhancing adverse effects 1

Evidence from Clinical Practice

• While some studies report minimal hypotensive effects with controlled administration, the risk remains clinically significant 4, 5
• A study examining intravenous prochlorperazine for vomiting control found that none of the 35 patients developed hypotension with careful dosing of 2.5-5.0 mg 4
• However, case reports document significant hypotensive episodes, particularly when combined with other medications that affect blood pressure 6
• In patients with cardiovascular compromise, the hypotensive effect may be more pronounced 7

Recommendations for Clinical Practice

• Monitor blood pressure when administering prochlorperazine, especially in patients with cardiovascular disease or those taking other medications that affect blood pressure 1, 8
• Use with caution in elderly patients, who may have a higher risk of orthostatic hypotension and falls 3
• Consider alternative antiemetics in patients with unstable blood pressure or cardiovascular disease 3, 8
• When prochlorperazine is necessary despite hypotension risk, use the lowest effective dose and monitor patients closely 8, 9

Prevention and Management

• To minimize hypotension risk, keep patients lying down after parenteral administration 1
• If hypotension occurs, place the patient in Trendelenburg position (head-low with legs raised) 1
• In severe cases requiring vasopressor support, LEVOPHED and NEO-SYNEPHRINE are recommended; importantly, epinephrine should be avoided as it may paradoxically worsen hypotension in patients receiving phenothiazines 1