Maximum dose of xylocaine with out adrenaline that can be given in 60kg adults is
**Core Concept**
The maximum dose of local anesthetics without adrenaline (epinephrine) is limited by systemic toxicity, particularly to the central nervous and cardiovascular systems. The dose is calculated based on the patient's weight and the local anesthetic's potency.
**Why the Correct Answer is Right**
The maximum dose of lignocaine (xylocaine) without adrenaline is 4 mg/kg. This is because lignocaine is a highly potent local anesthetic that can cause systemic toxicity at higher doses. The recommended maximum dose of 4 mg/kg is calculated based on the patient's weight, and it is essential to not exceed this dose to avoid adverse effects such as central nervous system toxicity (seizures, tremors) and cardiovascular toxicity (arrhythmias, cardiac arrest). Lignocaine works by blocking sodium channels in nerve fibers, which prevents depolarization and subsequent transmission of nerve impulses.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify a dose in milligrams per kilogram, making it impossible to determine its validity.
* **Option B:** This option is incorrect because it is lower than the recommended maximum dose of 4 mg/kg, making it an underestimation.
* **Option C:** This option is incorrect because it is higher than the recommended maximum dose of 4 mg/kg, making it an overestimation.
**Clinical Pearl / High-Yield Fact**
When administering local anesthetics without adrenaline, it is essential to monitor the patient's vital signs and neurological status closely, as systemic toxicity can occur rapidly.
**Correct Answer:** B. 7 mg/kg