Piperoxan is the first antihistamine was discovered. Piperoxan protected guinea pigs against histamine-induced bronchospasm. The piperoxan has been used to provoke anxiety behaviors in the monkey. Piperoxan is an alpha-adrenergic antagonist. Piperoxan has been claimed to preferentially block presynaptic alpha-adrenoreceptors leading to an increase in noradrenaline release and by this way the postsynaptic alpha-adrenoreceptors blockade may be overcome. There was clear evidence that piperoxan enhanced myocardial performance. Piperoxan is a diagnostic aid used in studies of hypertension.

Isometheptene (usually as isometheptene mucate) is a sympathomimetic amine sometimes used in the treatment of migraines and tension headaches due to its vasoconstricting properties. Isometheptene's vasoconstricting properties arise through activation of the sympathetic nervous system via epinephrine and norepinephrine. These compounds elicit smooth muscle activation leading to vasoconstriction by interacting with cell surface adrenergic receptors.

Isometheptene (usually as isometheptene mucate) is a sympathomimetic amine sometimes used in the treatment of migraines and tension headaches due to its vasoconstricting properties. Isometheptene's vasoconstricting properties arise through activation of the sympathetic nervous system via epinephrine and norepinephrine. These compounds elicit smooth muscle activation leading to vasoconstriction by interacting with cell surface adrenergic receptors.

Isometheptene (usually as isometheptene mucate) is a sympathomimetic amine sometimes used in the treatment of migraines and tension headaches due to its vasoconstricting properties. Isometheptene's vasoconstricting properties arise through activation of the sympathetic nervous system via epinephrine and norepinephrine. These compounds elicit smooth muscle activation leading to vasoconstriction by interacting with cell surface adrenergic receptors.

Tolazoline, also known as priscoline, was used in treatment of persistent pulmonary hypertension of the newborn. But that prescription was discontinued. Priscoline given intravenously produces vasodilatation, primarily due to a direct effect on vascular smooth muscle, and cardiac stimulation; the blood pressure response depends on the relative contributions of the two effects. Priscoline usually reduces pulmonary arterial pressure and vascular resistance. The mechanisms of its therapeutic effects are not clear, but is known, that tolazoline is a non-selective competitive α-adrenergic receptor antagonist and it possesses histamine agonist activity.

dl-α-tocopheryl phosphate has a growth acceleration effect on domestic fowl. Also was confirmed, that in all investigated animals dl-α-tocopheryl phosphate has an ability to being converted into vitamin E.

Domitor (medetomidine hydrochloride) is indicated for use in dogs: for restraint, sedation and analgesia associated with clinical examinations and procedures, minor surgery, pre-anaesthesia and as a premedicant before thiopentone-halothane general a naesthesiaand as a premedicant before general anaesthesia with propofol. In combination with butorphanol for sedation and analgesia, and as a premedicant prior to thiopentone anaesthesia. In cats: for restraint and sedation. Medetomidine is a potent and highly selective alpha2-adrenoreceptor agonist with both central and peripheral activity, and acting both presynaptically and postsynaptically. Its primary effects are sedative and analgesic resulting from its central depressant activity. It has no local anaesthetic properties. Like other compounds of its class there are secondary effects, including bradycardia. Blood pressure is increased but then returns to normal or just below. Body temperature is decreased in a dose dependent manner and intestinal motility is also reduced. The drug has been developed by Orion Pharma. It is currently approved for dogs in the United States, and distributed in the United States by Pfizer Animal Health and by Novartis Animal Health in Canada under the product name Domitor. The marketed product is a racemic mixture of two stereoisomers; dexmedetomidine is the isomer with more useful effects, and is now marketed as Dexdomitor.

Melengestrol is a steroidal progestin and antineoplastic agent which was never marketed. An acylated derivative, melengestrol acetate, is used as a growth promoter in animals. Melengestrol acetate (MGA) is one of six steroidal hormone growth promoters approved for use in Canada and USA. These products are used to improve growth rate and feed efficiency, as well as to suppress estrus in beef heifers (CFIA 2008). They are not approved for use in any species other than beef cattle meant for slaughter. MGA is the only drug of its kind that is administered in animal feed, and its labelled dose in Canada is 0.4mg per heifer per day (CFIA 2008). A mandatory withdrawal of 2 days before slaughter is applied to any animal that is administered MGA.

Ornithine is an amino acid produced in the urea cycle by the splitting off of urea from arginine. It is a central part of the urea cycle, which allows for the disposal of excess nitrogen. Ornithine is also a precursor of citrulline and arginine. Arginine stimulates the pituitary release of growth hormone. Burns or other injuries affect the state of arginine in tissues throughout the body. As de novo synthesis of arginine during these conditions is usually not sufficient for normal immune function, nor for normal protein synthesis, ornithine may have immunomodulatory and wound-healing activities under these conditions (by virtue of its metabolism to arginine).

Xylazine was developed as an antihypertensive agent. During clinical studies in people xylazine was found to have excessive central nervous system depressant effects and it was subsequently introduced for veterinary use as a sedative, analgesic and relaxant. Xylazine is a potent alpha-2 adrenergic agonist. Xylazine in horses and Cervidae may occasionally cause slight muscle tremors, bradycardia with partial A-V heart block and a reduced respiratory rate. Movement in response to sharp auditory stimuli may be observed.