Milrinone
Chemical
Selective PDE III inhibitor → pipyridine derivative
Use
Cardiac failure (acute)
Dose
Load: 50mcg/kg over 15 mins
Infusion: 0.5mcg/kg/min
Presentation
10mg/10ml ampoules, clear and colourless
Route
IV/PO
Onset
5 – 15 mins
DoA
t ½ 3 hrs
MoA
Competitive inhibition PDE III
- ↓hydrolysis of cAMP ∴↑cAMP of myocardium & smooth m.
Β1 Receptor of Heart = ↑Ca++
+ inotropy
+ chronotropy
+ dromotropy
Β2 Receptor of Heart = ↑Ca++
+ inotropy
Β2 Receptor of Smooth m.
Inhibits MLCK
↓
Smooth m. relaxation
PD
CVS
- +ve inotropy
- Vasodilation
- Minimal effect on HR & myocardial O2 consumption
PK
A
OBA 92% (IV only in Hus)
D
PPB 80%
VD 0.4L/kg
M
10% hepatically metabolized
E
Renally excreted
80% unchanged → renal dose adjustment
Adverse Effects
↓SVR