## **Core Concept**
Isotretinoin is a retinoid used primarily for the treatment of severe acne. It works by reducing sebum production, which in turn reduces the presence of Propionibacterium acnes on the skin, thereby reducing inflammation and preventing scarring. Given its potential for side effects, isotretinoin has a defined cumulative dose.

## **Why the Correct Answer is Right**
The maximum cumulative dose of isotretinoin is a critical parameter because it is associated with the risk of relapse and side effects. A higher cumulative dose reduces the risk of relapse but increases the risk of side effects. The generally recommended maximum cumulative dose of isotretinoin for the treatment of acne is **120-150 mg/kg**, as studies have shown that this range provides an optimal balance between efficacy and safety.

## **Why Each Wrong Option is Incorrect**
- **Option A:** 50 mg/kg - This dose is too low and would likely result in a high relapse rate for many patients.
- **Option B:** 100 mg/kg - Although closer, this is still below the generally recommended maximum cumulative dose.
- **Option D:** 200 mg/kg - This dose exceeds the typical recommended maximum and would unnecessarily increase the risk of side effects without a significant increase in benefit for most patients.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the risk of **teratogenicity** with isotretinoin is very high, and thus, strict contraception measures are required for female patients. Additionally, liver function tests and lipid profiles should be monitored during treatment.

## **Correct Answer:** . 120-150 mg/kg