It is writer Curtis Hartman, not Mark Hughes, who doesn't quite have his facts straight. A Dexamyl "Spansule" capsule contains 10 milligrams of Dexedrine (dextroamphetamine sulphate) and 65 milligrams of amobarbital, a derivative of barbituric acid.
All of Mrs. Hughes's side effects described by Mark Hughes in his sales presentation are true. Thousands of Americans (mostly women) were addicted to physician-prescribed amphetamine preparations in the 1950s through the 1970s.
Dexamyl, containing both amphetamine and barbiturate components, is indeed classified by the Drug Enforcement Administration as an amphetamine, not a barbiturate.