Maximum dose of lignocaine with adrenaline is (in mg/ kg)

**Core Concept**
Lignocaine with adrenaline is a combination of the local anesthetic lignocaine and the vasoconstrictor adrenaline. This combination is used to prolong the duration of action of lignocaine and reduce systemic toxicity. The maximum dose of lignocaine with adrenaline is limited by the dose of lignocaine, as adrenaline does not affect lignocaine toxicity.

**Why the Correct Answer is Right**
The maximum dose of lignocaine with adrenaline is 7 mg/kg without any upper limit for the adrenaline component. The lignocaine dose is limited by the risk of systemic toxicity, including central nervous system (CNS) and cardiovascular effects. The addition of adrenaline reduces lignocaine absorption and prolongs its duration of action, but does not affect its maximum safe dose.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because there is no established upper limit for lignocaine with adrenaline that would justify a lower dose.
* **Option B:** This option is incorrect because the dose of lignocaine with adrenaline is not reduced in patients with liver or kidney disease.
* **Option C:** This option is incorrect because the dose of lignocaine with adrenaline is not reduced in patients with a history of allergy to local anesthetics.

**Clinical Pearl / High-Yield Fact**
When administering lignocaine with adrenaline, it is essential to consider the maximum dose of lignocaine and the potential for systemic toxicity. The addition of adrenaline does not reduce the risk of lignocaine toxicity, but rather prolongs its duration of action.

**Correct Answer: A. 7 mg/kg**