Antihistamines (sedating vs non-sedating)

Question 1

Which antihistamines are sedating?

Answer 1

aka first-generation antihistamines

Chlorphenamine

Question 2

Which antihistamines are non-sedating?

Answer 2

aka second-generation antihistamines

• loratadine
• cetrizine
• fexofenadine

Question 3

antihistamines - indications

Answer 3

allergies - especially hayfever

itchiness (pruritus) and hives (urticaria)

adjunctive treatment in anaphylaxis, after administration of adrenaline and other life-saving measures

Question 4

antihistamines - adverse effects

Answer 4

first generation antihistamines (chlorphenamine) cause sedation

second generation antihistamines do not generally have any adverse effects

Question 5

antihistamines - interaction

Answer 5

none

Question 6

antihistamines - contraindications

Answer 6

safe in most patients

sedating antihistamines should be avoided in severe liver disease

• may precipitate hepatic encephalopathy