Agonist compounds of the histamine H.sub.3 receptor for therapeutic use, pharmaceutical compositions acting as agonists of the said receptor and preparation process are disclosed.The compounds are derived from an amine R-NH.sub.2 having a high affinity for the histamine H.sub.3 receptor and to the primary amine function of which a group which gives rise to a bond that is capable of being slowly hydrolyzed in a neutral medium is attached. The pharmaceutical compositions contain these compounds and a pharmaceutically acceptable vehicle or excipient.These compounds are used for producing a medicinal product which inhibits the synthesis and the release of histamine, in particular, possessing sedative, sleep-regulating, anticonvulsant, antidepressant, anti-allergic, anti-inflammatory, antisecretory or anti-ulcerous effects.