Steroid
Ex) Cholesterol, Testosterone, Progesterone, Estrogen, etc.
Quinine (Quinoline ring)
Ex) Antimalarial drugs (chloroquine)
Penicillins
(Beta-Lactan)
Barbiturates
Ex) Phenobarbital
Anesthetics
Amides or Esters attached to aromatic ring
Ex)Lidocaine
Morphines
Ex) Heroin, codeine
Benzomorphans
Phenylpiperidines
-Common in opioid formulations
Benzodiazepines