Dosing and uses of amrinone (inamrinone)
Adult dosage forms and strengths
injectable solution
- 5mg/mL
Congestive Heart Failure
Load: 0.75 mg/kg IV bolus over 2-3 minutes, THEn
5-10 mcg/kg/min IV
Total daily dose (including loading dose) should not exceed 10 mg/kg/day
Therapeutic dosage range: 0.5-7 mcg/mL
Renal Impairment
CrCl <10 mL/min: Administer 50-75% of the dose
CrCl ≥10 mL/min: Dosage adjustment not required
Pediatric dosage forms and strengths
injectable solution
- 5mg/mL
Congestive Heart Failure
<28 days old
- Load as in adults, 0.75 mg/kg IV over 3-5 minutes, THEN
- 3-5 mcg/kg/min IV maintenance infusion
- Bolus dose may need to be repeated after 30 minutes
- Total daily dose should not exceed 10 mg/kg/day
- Therapeutic dosage range: 0.5-7 mcg/mL
>28 days old
- Load as in adults, 0.75 mg/kg IV over 3-5 minutes, THEN
- 5-15 mcg/kg/min IV
- Not to exceed 10 mg/kg/day
- Therapeutic dosage range: 0.5-7 mcg/mL
Renal Impairment
CrCl ≥30 mL/min: Dose adjustment not necessary
CrCl 10-29 mL/min: Administer 50% of dose
CrCl <10 mL/min: Administer 25% of dose
Geriatric dosage forms and strengths
Congestive Heart Failure
Load: 0.75 mg/kg IV bolus over 2-3 minutes, THEn
5-10 mcg/kg/min IV
Total daily dose (including loading dose) should not exceed 10 mg/kg/day
Therapeutic dosage range: 0.5-7 mcg/mL
amrinone (inamrinone) adverse (side) effects
1-10%
Arrhythmia (3%)
Thrombocytopenia (2.4%)
Nausea (1.7%)
Hypotension (1.3%)
<1%
Fever (0.9%)
Vomiting (0.9%)
Abdominal pain (0.4%)
Anorexia (0.4%)
Chest pain (0.2%)
Injections site pain (0.2%)
Hepatotoxicity (rare)
Warnings
Contraindications
Hypersensitivity to inamrinone, milrinone and bisulfites
Cautions
Recent MI
Electrolyte abnormalities
Hypotension
Proarrhythmic effects
Insufficient cardiac filling pressure
Severe aortic or pulmonic valvular diseas
Renal impairment
Concurrent use of disopyramide (may cause hypotension)
Pregnancy and lactation
Pregnancy category: C
Lactation: excretion in milk unknown; use with caution
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of amrinone (inamrinone)
Mechanism of action
Positive inotrope with direct pulmonary vasodilator (decrease both preload & afterload) activity, which increases cardiac output; these effects result from increases in cellular levels of cAMP as inamrinone inhibits myocardial cAMP phosphodiesterase
Pharmacokinetics
Half-Life: 3.6-5.8 hr (longer in CHF)
Onset: 5-10 min (initial effect); within 10 min (max effect)
Duration: 0.5-2 hr, duration depends on dose, mutiple doses: 8 hr
Protein Bound: 10-49%
Vd: 1.2 L/kg
Metabolism: In the liver, main metabolic pathway is conjugation
Metabolites: N-glycolate, N-acetate, N-glucuronide, O-glucuronide (inactive)
Excretion: Urine 10-40%, feces 18%
Dialyzable: No (HD or PD)
Administration
IV Incompatibilities
Solution: D5W
Additive: furosemide
Y-site: procainamide(?), Na bicarB
IV Compatibilities
Solution: 1/2Ns
Additive: propafenone
Syringe: propranolol, verapamiL
Y-site (partial list): atropine, CaCl2, digoxin, dobutamine, dopamine, epinephrine, hydrocortisone, isoproterenol, methylprednisolone, nitroglycerin, norepinephrine, phenylephrine, KCl, propofol, propranolol, verapamiL
IV Preparation
Dilute inamrinone with 1/2NS or NS to 1-2 mg/mL concentration for IV infusion
Use within 24 hr
IV Administration
IV injection
- May administer undiluted
- Use only for initial loading & additional bolus doses
- Over 2-3 min
IV infusion
- Use for maintenance doses
- Infuse continuously at 5-15 mcg/kg/min
Storage
Store intact vials at room temp; protect from light
Use diluted soln within 24 hr
