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.

Tripelennamine (sold as Pyribenzamine by Novartis) is a drug that is used as an antipruritic and first-generation antihistamine. Histamine acting on H1-receptors produces vasodilatation, hypotension, flushing, headache, tachycardia, and bronchoconstriction. Histamine also increases vascular permeability and potentiates pain. Tripelennamine can be used in the treatment of asthma, hay fever, rhinitis, and urticaria, but is now less common as newer antihistamines have replaced it.

Sulfamethazine is a sulfonamide used to treat a variety of bacterial diseases in animals. It inhibits bacterial synthesis of dihydrofolic acid by competing with para-aminobenzoic acid (PABA) for binding to dihydropteroate synthetase (dihydrofolate synthetase).

Desoxycorticosterone pivalate (DOCP) is a mineralocorticoid hormone and an analog of desoxycorticosterone. DOCP is a long-acting ester of desoxycorticosterone acetate (DOCA) which is recognized as having the same qualitative effects as the natural mineralocorticoid hormone aldosterone. It’s used as Percorten-V for replacement therapy for the mineralocorticoid deficit in dogs with primary adrenocortical insufficiency. Percorten-V is only available in the U.S., Canada, Australia and recently, Denmark. Percorten was originally developed for the treatment of Addison's disease in humans but the demand for it decreased significantly once Florinef was available. Unaware that their product was being prescribed “off-label” for the treatment of canine Addison’s Disease and faced with a decreased demand for Percorten, the manufacturer *almost* discontinued production until the veterinary community rose up and voiced their distress. Field trials were run and the FDA approved the use of Percorten-V (the "v" is for veterinary). DOCP like other adrenocorticoid hormones is thought to act by controlling the rate of synthesis of proteins. It reacts with receptor proteins in the cytoplasm to form a steroid-receptor complex. This complex moves into the nucleus, where it binds to chromatin that result in genetic transcription of cellular DNA to messenger RNA. The steroid hormones appear to induce transcription and synthesis of specific proteins, which produce the physiologic effects seen after administration. The most important effect of DOCP is to increase the rate of renal tubular absorption of sodium. This effect is seen most intensely in the thick portion of the ascending limb of the loop of Henle. It also increases sodium absorption in the proximal convoluted tubule but this effect is less important in sodium retention. Chloride follows the sodium out of the renal tubule. Another important effect of DOCP is enhanced renal excretion of potassium. This effect is driven by the resorption of sodium that pulls potassium from the extracellular fluid into the renal tubules, thus promoting potassium excretion.

Sodium thiopental (also known as Sodium Pentothal, thiopental) was discovered in 1930s by investigators working for Abbott Laboratories. Thiopental sodium was used for the induction of general anesthesia and is used as an adjunct to provide hypnosis during balanced anesthesia with other anesthetic agents, including analgesics and muscle relaxants. Thiopental sodium was also used as an adjunct for control of convulsive disorders of various etiology, including those caused by local anesthetics. Finally, thiopental sodium had been used to reduce the intracranial pressure in patients with increased intracranial pressure, if controlled ventilation is provided. Nevertheless, these prescriptions of drug were discontinued. In addition, this drug was banned for use in US executions. Thiopental sodium acts through the CNS with particular activity in the mesencephalic reticular activating system. It was shown, that mechanism of action of sodium thiopental via GABAA receptor. Thiopental binds at a distinct binding site associated with a Cl- ionopore at the GABAA receptor, increasing the duration of time for which the Cl- ionopore is open. The post-synaptic inhibitory effect of GABA in the thalamus is, therefore, prolonged.

Oleic acid is an unsaturated fatty acid that is the most widely distributed and abundant fatty acid in nature. It is used commercially in the preparation of oleates and lotions, and as a pharmaceutical solvent. Oleic acid occurs naturally in various animal and vegetable fats and oils. It is a component of the normal human diet as a part of animal fats and vegetable oils. Oleic acid may be responsible for the hypotensive (blood pressure reducing) effects of olive oil. Oleic acid has being shown to have a potential anticancer activity.

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.

Melarsomine (melarsomine dihydrochloride) is an organic arsenical chemotherapeutic agent and is a trypanocidal antiparasitic drug. As of 2016 DIROBAN, a generic melarsomine dihydrochloride product, is the only FDA-approved treatment for adult heartworm (Dirofilaria immitis) infection in dogs. It is not approved for treatment in cats, or dogs in late-stage infection. It is marketed by Merial under the trade name Immiticide and is not currently available in the U.S. due to a manufacturing shortage. Sponsored by Anzac Animal Health, LLC and distributed by Zoetis, Inc., DIROBAN is a prescription animal drug supplied as a sterile powder that must be reconstituted with an accompanying sterile water diluent. The exact mode of action on D. immitis is unknown. Post-treatment mortality due to thromboembolism and/or progression of the underlying disease may occur in 10 to 20% of the Class 3 patients treated with DIROBAN.

Imidocarb is a carbanilide derivative with antiprotozoal activity. It is usually administered as the dipropionate salt. Imidocarb is a drug sold under the brand name Imizol and is used to treat canine ehrlichiosis. wo mechanisms of action have been proposed: As the effect of imidocarb on Trypanosoma brucei is antagonized by excess polyamines, it is has been suggested that imidocarb interferes with their production and/or use. Imidocarb blocks the entry of inositol into erythrocytes containing Babesia, resulting in starvation of the parasite. It is generally accepted in that imidocarb has anticholinesterase activity.