Double-blind, randomized, placebo-controlled clinical trials with non-prescription medications for the treatment of obesity.
OBJECTIVE
Phenylpropanolamine (PPA) and benzocaine are non-prescription medications approved for treating obesity. The dose of PPA for weight loss is 75 mg/day. PPA has the same chemical similarity to pseudoephedrine that amphetamine has to methamphetamine. Because benzocaine causes weight loss by altering taste and PPA by central appetite suppression, they may induce additional weight loss when combined. These studies explore the safety and efficacy of low-dose PPA, pseudoephedrine, and PPA with benzocaine in causing weight loss.


METHODS
Study 1 compared PPA 12.5 mg tid with 25 mg tid and placebo in a 6-week trial in 108 obese subjects. Study 2 compared pseudoephedrine 120 mg/day and a placebo in a 12-week trial with 72 obese subjects. Study 3 compared 4 groups of 20 obese subjects using PPA 75 mg/day, benzocaine gum 96 mg/day, PPA with benzocaine gum, and a placebo over 12 weeks.


RESULTS
Both doses of PPA gave twice the weight loss of placebo, but the difference did not reach statistical significance. Pseudoephedrine was no different than placebo in inducing weight loss. The PPA with benzocaine group had more adverse events than the benzocaine group (p = 0.03), the placebo group (p = 0.03), or the PPA group (p = 0.09) without additional weight loss.


CONCLUSIONS
We conclude that further studies with low-dose PPA for weight loss are indicated, that pseudoephedrine is not effective for weight loss, and that adding benzocaine to phenylpropanolamine increases adverse effects without increasing weight loss.
Greenway
F
F
Pennington Biomedical Research Center, Baton Rouge, LA 70808-4124, USA. greenfl@mhs.pbrc.edu
Herber
D
D
Raum
W
W
Herber
D
D
Morales
S
S
D000293:Adolescent; D000328:Adult; D000368:Aged; D001067:Appetite Depressants / Q000008:administration & dosage / Q000627:therapeutic use*; D001566:Benzocaine / Q000008:administration & dosage / Q000627:therapeutic use*; D003692:Delayed-Action Preparations / Q000008:administration & dosage / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D004809:Ephedrine / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D004366:Nonprescription Drugs / Q000008:administration & dosage / Q000627:therapeutic use*; D009765:Obesity / Q000188:drug therapy*; D010665:Phenylpropanolamine / Q000008:administration & dosage / Q000627:therapeutic use*; D015431:Weight Loss
D001067:Appetite Depressants; D003692:Delayed-Action Preparations; D004366:Nonprescription Drugs; D010665:Phenylpropanolamine; D004809:Ephedrine; D001566:Benzocaine