U2vi: Outline the pharmacology of glucagon

Glucagon

Glucagon

Chemical

Polypeptide hormone extracted from α cells of pancreas

Use

  1. Hypoglycaemia rescue
  2. β-blocker OD

Presentation

  • 1mg/mL pre-filled syringe
  • 1mg/10mg powder reconstituted with H2O in vials

Dose

  • 1 – 2mg IM (hypoglycaemia)
  • 5mg → 5mg IV bolus → infusion (β-blocker OD)

Route

IV/IM

Onset

8 – 10 mins IM

1 min IV

DoA

↑BSL lasts 30 mins

MoA

  • Agonist of glucagon receptor
  • GS GPCR
  • ↑Adenyl cyclase activity
  • ↑cAMP → protein kinase cascade

PD

(systems)s

  • CVS
    • +ve inotropy
    • +ve chronotropy
  • ENDO
    • ↑glycogen breakdown
    • ↑gluconeogenesis
    • ↑ketogenesis
    • ↑protein + fat catabolism
    • ↑BSL + ketones
  • GI
    • ↓tone
    • Sphincter relaxation
  • CNS
    • ↑catecholamine release
    • Hunger
    • Tremor
    • Agitation

PK

A

IV 1 – 3min

IM 10min

Orally degraded

D

VD 0.25L/kg

M

Rapid proteolysis in plasma, liver, kidneys

E

t½ 8min 

Adverse Effects

Vomiting, diarrhoea, hyperglycaemia, hypokalaemia