Recently, a combination of the
anorectics fenfluramine (FEN) and
phentermine (PHEN) has been used to treat
obesity. While each of these agents has been investigated in animals, little is known concerning the effects of the combination on ingestive behavior and
body weight. In the present experiments, we report: (1) the effects of acute administration of
dexfenfluramine (DFEN) and PHEN individually and in combination on sweetened milk intake and
body weight in non-deprived rats and (2) the effects of chronic administration (7 day minipump) of DFEN, PHEN, and their combination on daily food intake and
body weight both during and after the treatment period. Additionally, the effects of the
5-HT2C agonist 1-[3-(trifluoromethyl)-phenyl]
piperazine (
TFMPP) alone and in combination with PHEN on food intake and
body weight were assessed. Both acute and chronic administration of DFEN and PHEN revealed that in combination they are more effective than when given individually. However, the DFEN/ PHEN combination does not appear to exert effects that are selective for food intake because water intake was markedly suppressed in water-deprived rats. PHEN alone or in combination with either DFEN or
TFMPP also produced increased activity or alertness during the day when controls normally were asleep. While
anorectic combinations such as DFEN/PHEN may be effective at promoting
weight loss and reducing food intake, future studies on their specificity, safety and efficacy are warranted.