Phenothiazines

[RD5:p374]

• Anti-dopamine (D2) at the CTZ
• Also some degree of antagonist activity at
  * Histamine receptors
  * Muscarinic acetylcholine receptors
  * Other receptors (e.g. adrenergic)
• Can be used for N&V associated with motion sickness, vertigo, and migraine, uraemia, radiation, viral gastroenteritis, severe morning sickness

Comparison

Chlorpromazine (largatil)

	Chlorpromazine (Largatil)	Prochlorperazine (Stemetil)
Sedation	+++	+
Anticholinergic	++	+
Extrapyramidal	++	+++

Phenothiazine group side-effects

CNS effects

• Sedation
• Extrapyramidal effects
  * Due to antidopamine effects
  * e.g. Dystonia and tardive dyskinesia
• Seizures
• Neuroleptic malignant syndrome
  * [???] ??? Need more info

CVS effects

• Due to antiadrenergic effects
• Hypotension

Haematological effects

• Agranulocytosis
• Aplastic anaemia
• Haemolytic anaemia

Other effects

• Skin sensitization
• Cholestatic jaundice
• Hyperprolactinaemia
  * Dopamine normally suppresses prolactin