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With increasing numbers of obese patients presenting for surgery, it is important to consider dosing regimens for certain medications. In general, most medications should be dosed based on lean body weight. However, certain medications are more appropriately dosed according to total body weight. Succinylcholine should be dosed according to total body weight because obese patients have increased extracellular volume and increased plasma pseudocholinesterase activity. Therefore, to achieve an adequate level of paralysis for intubation, succinylcholine should be administered based on total body weight. Some other medications (e.g., cisatracurium) should be dosed according to total body weight when administered as a single loading dose, but should be dosed according to lean body weight when administered as a maintenance dose or infusion. Lean body weight is total body weight minus fat weight.