What is the ketamine induction dose via the IM route?

What is the ketamine induction dose via the IM route?

• A. IV 1-2 mg/kg
• B. IM 4-8 mg/kg
• C. PO 10 mg
• D. IM 2-4 mg/kg

Answer: (B)

Ketamine dosing depends on the route because how quickly and how well the drug enters the bloodstream changes with administration method. For the IM route, absorption from muscle is slower and more variable than IV, so a higher dose is needed to achieve the same depth of anesthesia. That’s why the induction dose given IM is in the 4-8 mg/kg range. This dose reliably produces dissociative anesthesia while often preserving airway reflexes and spontaneous breathing, with onset in a few minutes and a short duration. The other options don’t fit for induction via the IM route: an IV induction dose is typically 1-2 mg/kg, which is lower because absorption is immediate; an oral dose around 10 mg is not appropriate for induction due to very low and unpredictable bioavailability; an IM dose of 2-4 mg/kg is generally not sufficient to guarantee reliable induction in many patients.

Ketamine dosing depends on the route because how quickly and how well the drug enters the bloodstream changes with administration method. For the IM route, absorption from muscle is slower and more variable than IV, so a higher dose is needed to achieve the same depth of anesthesia. That’s why the induction dose given IM is in the 4-8 mg/kg range. This dose reliably produces dissociative anesthesia while often preserving airway reflexes and spontaneous breathing, with onset in a few minutes and a short duration.

The other options don’t fit for induction via the IM route: an IV induction dose is typically 1-2 mg/kg, which is lower because absorption is immediate; an oral dose around 10 mg is not appropriate for induction due to very low and unpredictable bioavailability; an IM dose of 2-4 mg/kg is generally not sufficient to guarantee reliable induction in many patients.