Mefenorex is a anti-obesity drug with little CNS stimulant activity. The drug was marketed under names Incital, Pondinil, Amexate, Rondimen, however it was withdrawn due to unfavourable benefit/risk balance.

Mefenorex:
https://drugs.ncats.io/drug/7FT4O2NC8G

Why is Mefenorex no longer used as a weight loss drug?
It's a amphetamine derivative like Ritalin. It's actually a prodrug for amphetamine. It's relatively weak but still...an amphetamine derivative. We've learned that class of drug has more downsides than upsides for weight loss.

With regards to drugs the blanket answer in almost all cases of, "Why is XYZ no longer used for ZYX is the downsides don't warrant the upsides.

Why is Mefenorex no longer used as a weight loss drug?
https://www.quora.com/Why-is-Mefenorex-no-longer-used-as-a-weight-loss-drug

Mefenorex is a stimulant drug which was used as an appetite suppressant. It is an amphetamine derivative which was developed in the 1970s and used for the treatment of obesity. Mefenorex produces amphetamine as a metabolite. It has been withdrawn in many countries despite having only mild stimulant effects and relatively little abuse potential.