Promethazine

Question 1

What is Promethazine

Answer 1

a phenothiazine. an H1-antagonist

Question 2

what effects does Promethazine have

Answer 2

anticholinergic, sedative, and antiemetic effects and some local anaesthetic properties

Question 3

Class

Answer 3

Histamine H1 receptor antagonist

Question 4

Action

Answer 4

Antiemetic

Sedative

Question 5

Mechanisms of Actions

Answer 5

Reversible competitive
antagonist at H1 receptors Antiemetic action is due to
blocking H1 receptors in
the vestibular nuclei and in
the vomiting centre

Question 6

Clinical Uses

Answer 6

Motion sickness and
other emesis of vestibular origin
Vomiting in early
pregnancy
Emesis due to local
stimuli in the gut acting
via the vagus

Question 7

Adverse Effects

Answer 7

Sedative action may
not be desirable Causes confusion in
elderly
Dry mouth
(anticholinergic
action)
Potentially fatal
respiratory depression
in infants under 2
years old