Neonatal Drug Dose Calculation:

Step 1: Calculate required dose:

\[\text{Dose} = 5\,\text{mg/kg} \times 4\,\text{kg} = 20\,\text{mg}\]

Step 2: Calculate volume to administer:

\[\text{Volume} = \frac{\text{Required dose}}{\text{Concentration}} = \frac{20\,\text{mg}}{10\,\text{mg/mL}} = 2\,\text{mL}\]

Administration: Administer 2 mL IV over 30–60 minutes (slow infusion to prevent ototoxicity and nephrotoxicity).

Gentamicin monitoring in neonates:

• Therapeutic drug monitoring (TDM) is mandatory
• Trough level (before next dose): target \(<1\,\mu\text{g/mL}\) (extended interval dosing)
• Peak level (1 hr post-dose): target \(6{-}12\,\mu\text{g/mL}\)
• Monitor renal function (serum creatinine) and hearing (ototoxicity)

Why extended interval (48 hr) in neonates? Neonates have larger volume of distribution and immature renal function → longer half-life → risk of accumulation with daily dosing.