Fatal intravascular immune hemolysis induced by hydrochlorothiazide

Area of Science:

• Pharmacology
• Immunology
• Hematology

Background:

• Antihypertensive medications, including thiazides, are widely prescribed for managing high blood pressure.
• Immune-mediated adverse drug reactions can manifest in various clinical scenarios.
• Thiazide diuretics are a common class of drugs used in cardiovascular therapy.

Observation:

• A patient undergoing antihypertensive treatment experienced a sudden and severe episode of acute intravascular hemolysis.
• The patient ultimately succumbed to the hemolytic event.
• The hemolysis was identified as an immune process triggered by an antibody against thiazide.

Findings:

• This case represents the third documented instance of thiazide-induced immune hemolytic anemia.
• The observed hemolysis appears to be specifically associated with the concurrent use of thiazide and methyldopa.
• Antibody formation against thiazide was confirmed as the causative mechanism.

Implications:

• This case highlights a rare but potentially fatal adverse drug reaction associated with thiazide therapy.
• Clinicians should be vigilant for signs of hemolysis in patients treated with thiazides, particularly when co-prescribed with methyldopa.
• Further investigation into the immunopathogenesis of thiazide-induced hemolysis may inform safer prescribing practices.