Table 1.

Drugs with an FDA-approved indication for obesity. Only orlistat, lorcaserin, and phentermine/topiramate-ER are FDA-approved for long-term use; the others are approved only for short-term use (i.e., a few weeks).

Generic Name	Trade Name(s)	Mechanism of action	Dosage	Whole-sale price per mo.*	Mean weight change relative to placebo at 1y, kg**	Interactions	Contraindications&	Common Adverse Events&	Cautions and Warnings&
Phenterminea	Adipex-P, Fastin, Oby-Cap, lonamin, Others	Noradrenergic causing appetite suppression	15– 37.5mg/d	$6– $45	Not Available	Guanethidine, CNS stimulants, alcohol, tricyclic antidepressants; requirements for insulin or oral hypoglycemic medications may be altered	Pregnancy or nursing, advanced cardiovascular disease, uncontrolled hypertension, hyperthyroidism, glaucoma, agitated states, history of drug abuse, MAOIs	Insomnia, elevation in heart rate, dry mouth, taste alterations, dizziness, tremors, headache, diarrhea, constipation, vomiting, gastro- intestinal distress, anxiety, and restlessness.	Do not increase beyond recommended dose if tolerance to the anorexiant effect develops. Caution prescribing to patients with even mild hypertension. Caution for patients using alcohol or other CNS active drugs or engaging in hazardous activity.
Diethylpropiona	Tenuate, Tenuate Dospan, Tepanil	Noradrenergic causing appetite suppression	25mg 3 times/d or 75mg sustained- release/d	$47– $120	Not Available	Same as phentermine	Same as phentermine	Same as phentermine	Same as phentermine
Phendimetrazineb	Bontril	Noradrenergic	17.5–70mg 2–3 times/d or 105mg sustained- release/d	$6– $20	Not Available	Same as phentermine	Same as phentermine	Same as phentermine	Same as phentermine
Benzphetamineb	Didrex	Noradrenergic causing appetite suppression	25–50mg 1–3 times/d	$20– $50	Not Available	Same as phentermine	Same as phentermine	Same as phentermine	Same as phentermine
Orlistatc	Xenical, Alli	Lipase inhibitor causing excretion of ~30% of ingested triglycerides in stool	60 or 120mg 3 times/d within 1 hr of a fat- containing meals, plus a daily multi- vitamin	For 60mg TID: $45 For 120mg TID: $207	For 60mg TID:−2.5 kg (−1.5 to −3.5) For 120mg TID: −3.4 kg (−3.2 to −3.6)	Decreased drug concentrations of cyclosporine and levothyroxine. Doses should be temporally separated from orlistat. Fat soluble vitamin absorption is decreased by orlistat	Pregnancy, chronic malabsorption syndromes, cholestasis	Oily Spotting, Flatus with Discharge, Fecal Urgency, Fatty/Oily Stool, Increased Defecation, Fecal Incontinence	Use with caution in those at risk for renal insufficiency, since treatment may increase urinary oxalate. Cholelithiasis and, rarely, severe liver injury including hepatocellular necrosis and acute hepatic failure leading to death, have been reported
Lorcaserina	Belviq	Highly selective serotonergic 5-HT2C receptor agonist causing appetite suppression	10mg two times/d	$240	−3.2 kg (−2.7 to −3.8)	Triptans, MAOIs including linezolid, SSRIs, SNRIs, dextro- methorphan, tricyclic antidepressants, bupropion, lithium, tramadol, tryptophan, and St. John's Wort	Pregnancy	Headache, dizziness, fatigue, nausea, dry mouth, cough, and constipation, and back pain, cough and hypoglycemia in patients with type 2 diabetes.	Risk for Serotonin Syndrome or Neuroleptic Malignant Syndrome-like Reactions. Evaluate patients for signs or symptoms of valvular heart disease. Euphoria, hallucination, and dissociation have been seen with supra- therapeutic doses. Use with caution in men at risk for priapism
Phentermine / Topiramate-ERa	Qsymia	Noradrenergic + GABA- receptor activator, kainite/AMPA glutamate receptor inhibitor causing appetite suppression	3.75/23mg /d for 2 weeks, then 7.5/46mg/ d, escalating to a maximum of 15/92mg/d	$140 – $195	For 7.5/46mgd: −6.7 kg (−5.9 to −7.5) For 15/92mg/d −8.9 kg (−8.3 to −9.4)	Oral contraceptives, alcohol and other CNS depressants, non-potassium- sparing diuretics	Pregnancy, Glaucoma, Hyperthyroidism, MAOIs	Paresthesias dizziness, taste alterations, insomnia, constipation, dry mouth, elevation in heart rate, memory or cognitive changes	Metabolic acidosis, hypokalemia, and elevated creatinine have been reported, and periodic monitoring is advised. Increased risk of nephrolithiasis. Advise patients to report changes in mood/suicidalit y. Abrupt withdrawal of topiramate may cause seizures; taper over 1 week for patients using 15/92mg phentermine- topiramate-ER. There is an increased risk of oral clefts in offspring of women who become pregnant while taking topiramate.

MAOI: monoamine oxidase inhibitor, CNS: central nervous system, SSRI: selective serotonin-reuptake inhibitors, SNRI: selective serotonin-norepinephrine reuptake inhibitors.

^*Reference prices found on March 8, 2013.⁹⁹

^**Weight change relative to placebo (95 percentile confidence interval) using intent-to-treat analyses for each medication at 1 year. No studies for older noradrenergic agents (phentermine, diethylpropion, phendimetrazine, and benzphetamine) met inclusion criteria for length of treatment, sample size, and attrition.

^aMedications listed on Drug Enforcement Administration Schedule IV are associated with a lower risk of abuse than

^bmedications on Schedule III;

^cOrlistat is a non-Drug Enforcement Administration scheduled drug.

^&Common adverse events for noradrenergic agents include those listed as common in the NIDDK Weight-control Information Network Fact Sheet “Prescription Medications for the Treatment of Obesity”¹⁰⁰ as adverse event frequency is not available in the drug package inserts for these agents. For orlistat, lorcaserin, and phentermine/topiramate ER, common adverse events are those listed in the drug package inserts^48,52,54 that are reported to occur more frequently than placebo and with more than 5% prevalence.

See full prescribing information for all adverse effects, cautions, and contraindications.