Evaluating Muscle Weakness Improvement With Lorcaserin in ICU

Inclusion Criteria: * Age ≥18 years old * Sepsis \[ ≥2 Systemic Inflammatory Response Syndrome (SIRS) Criteria AND known or suspected infection\] * Muscle weakness \[Medical Research Council sum score \<48/60 or handgrip strength \<11 kg in men and \<7 kg in women\] * Obey Commands \[Score for DeJonghe Awakening Score of ≥3/5\] Exclusion Criteria: * Severe renal insufficiency \[Creatinine Clearance \<30 mL/min - or receiving dialysis\] * Acute infectious or auto-immune hepatitis, acute liver failure or a history of cirrhosis without liver transplant * History of psychosis * Bradycardia, or 2nd or 3rd degree Atrio-Ventricular block without pacemaker * History of valvular heart disease without valve replacement * History of priapism * Pre-existing cognitive impairment * Receiving drugs with serotonergic effects and/or CYP2D6 substrates which cannot be substituted stopped or titrated. * Receiving Sulfonylurea medication at the time of the study * Prior neuromuscular or central nervous system disease, including pre-existing neuropathy * Inability to perform study's muscle strength assessments based on patient's baseline status prior to hospital admission * Unable to receive, or unlikely to absorb study drug (e.g. bowel obstruction, ischemia, or infarction; short gut syndrome) * Body mass index \>40 * Patient not expected to survive \>4 days * Pregnancy or lactation * Allergy to lorcaserin or lorcaserin taken in the prior 7 days * Enrolled in another interventional drug or physical rehabilitation trial * Physician declines for patient to be enrolled * Patient or proxy declines consent * Unable to reach proxy for consent * Non-English speaking