Eltenac is a compound with a structural similarity to diclofenac with one benzol ring substituted by a tiophene ring. This modification has been shown to improve the absorption after topical application. Eltenac is an inhibitor of both cyclo-oxygenase-1 and -2. Eltenac had been in phase II clinical trial for the treatment of osteoarthritis of the knee. Eltenac is used in the alleviation of inflammation associated with musculoskeletal disorders and control of post-operative swelling, oedema and endotoxaemia in horses. The local skin reactions reported in humans were erythema, eczema, itching, rash and dry skin.

Etoricoxib is a selective COX-2 inhibitor, which is approved in Europe for the treatment of inflammatory disorders such as osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, acute pain conditions, gout and postoperative dental surgery pain.

Lonazolac is a nonsteroidal anti-inflammatory drug. The mononuclear cell response to a synovial stimulus can be abolished by very low concentrations of lonazolac. This blockade can be completely released by the addition of prostaglandin E2. Lonazolac appears therefore as an agent able in addition to modulate the immune response. The release of histamine from human basophils was significantly decreased after preincubation of the cells with lonazolac Ca. Preincubation of human polymorphonuclear leukocytes with lonazolac Ca led to an inhibition of leukotriene generation induced by either the Ca ionophore or opsonized zymosan. Lonazolac Ca affected different enzymes of the platelet activating factor metabolism. After pre- and post-treatment with lonazolac-Ca, the numbers of animals with lung metastases and the score of metastases significantly decreased. Lonazolac-Ca is indicated for the treatment of painful inflammatory rheumatic diseases of the joints and the spine. Acute irritation in osteoarthritis and spondylosis. Soft tissue rheumatism. Post-traumatic and postoperative pain and swelling states.

Mavacoxib (trade name Trocoxil) is a veterinary drug used to treat pain and inflammation in dogs with the degenerative joint disease. Mavacoxib is a non-steroidal anti-inflammatory drug (NSAID) of the coxib class. Mavacoxib acts by preferential inhibition of COX-2-mediated prostaglandin synthesis. It, therefore, possesses analgesic and anti-inflammatory properties. The products of COX-2 metabolism are also involved in ovulation, implantation, and closure of the ductus arteriosus. Mavacoxib is well absorbed after oral administration; bioavailability was 87% in fed dogs and 46 % in fasted conditions and the recommended dose is based on administration with food. Therapeutic concentrations in fed dogs are reached rapidly and peak concentrations are obtained in less than 24 hours after administering a dose. Mavacoxib is approximately 98% bound to plasma proteins. It is extensively distributed throughout the body and almost all the mavacoxib-related residues in plasma comprise parent drug. The rate of body clearance of mavacoxib is slow and the major route of elimination is by biliary excretion of the parent drug. Adverse reactions of the digestive tract such as vomiting and diarrhea were commonly reported, loss of appetite, hemorrhagic diarrhea, and melaena have been reported in uncommon cases. Gastrointestinal ulceration was reported in rare cases. Apathy, degradation of renal biochemistry parameters and impaired renal function have been reported in uncommon cases. In rare cases, these adverse reactions may be fatal.

Tepoxalin is a nonsteroidal anti-inflammatory drug approved for veterinary use in the United States and many other countries. Marketed under the brand name Zubrin, Tepoxalin is indicated for the control of pain and inflammation associated with osteoarthritis in dogs. Tepoxalin has an unique property as an NSAIDs that suppresses both cyclooxygenase and lipoxygenase.

Fenclofenac (Flenac) is a non-steroidal anti-inflammatory drug previously used in rheumatism. Fenclofenac was shown to possess anti-inflammatory, antinociceptive and antipyretic properties. Flenac is an acetic acid nonsteroidal antiinflammatory drug (NSAID) with analgesic and antipyretic properties. Flenac is used to treat pain, dysmenorrhea, ocular inflammation, osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, and actinic keratosis. It has mild immunosuppressive effects and may displace thyroid hormone from its binding protein. The antiinflammatory effects of Flenac are believed to be due to inhibition of both leukocyte migration and the enzyme cylooxygenase (COX-1 and COX-2), leading to the peripheral inhibition of prostaglandin synthesis. As prostaglandins sensitize pain receptors, inhibition of their synthesis is responsible for the analgesic effects of Flenac. Antipyretic effects may be due to action on the hypothalamus, resulting in peripheral dilation, increased cutaneous blood flow, and subsequent heat dissipation. Fenclofenac, despite passing animal toxicity tests in 10 animal species (mice, rats, guinea pigs, ferrets, rabbits, cats, dogs, pigs, horses, and monkeys), produced severe liver toxicity in humans. Due to its side effects it was withdrawn from the UK in 1984.

Lornoxicam (Xefo®) is a nonsteroidal anti-inflammatory drug of the oxicam class with analgesic, anti-inflammatory and antipyretic properties. It differs from other oxicam compounds in its potent inhibition of prostaglandin biosynthesis, a property that explains the particularly pronounced efficacy of the drug. The inhibition of the cyclooxygenase enzymes (COX-1 and COX-2) by lornoxicam (Xefo®) leads to desensitisation of peripheral nociceptors and consequently inhibition of inflammation. A central effect on nociception which seems to be independent of anti-inflammatory effects has also been suggested.

Tenoxicam (Mobiflex), an anti-inflammatory agent with analgesic and antipyretic properties, is used to treat osteoarthritis and control acute pain. The anti-inflammatory effects of tenoxicam may result from the inhibition of the enzyme cyclooxygenase and the subsequent peripheral inhibition of prostaglandin synthesis. As prostaglandins sensitize pain receptors, their inhibition accounts for the peripheral analgesic effects of tenoxicam. Antipyresis may occur by central action on the hypothalamus, resulting in peripheral dilation, increased cutaneous blood flow, and subsequent heat loss. Taking tenoxicam with other drugs can increase the chance of side effects or alter the therapeutic effect of tenoxicam or the other drug, depending on the combination. Drug types the tenoxicam may interact with include: other analgesic NSAIDs, salicylates such as aspirin, antacids, anticoagulants, cardiac glycosides, ciclosporin, quinolone antibiotics, lithium therapy, diuretics and anti-hypertensives, methotrexate, oral anti-diabetics, cholestyramine, dextromethorphan, mifepristone, corticosteroids, anti-platelet agents and selective serotonin reuptake inhibitors (SSRIs), tacrolimus, zidovudine, and gold/penicillamine. Tenoxicam is available as a prescription-only drug in the United Kingdom and other countries, but not in the US. Outside of the United Kingdom, tenoxicam is also marketed under brand names including Tilatil, Tilcitin, and Alganex. Tenoxicam belongs to the class of NSAIDs known as oxicams. It is used to relieve inflammation, swelling, stiffness, and pain associated with rheumatoid arthritis, osteoarthritis, ankylosing spondylitis (a type of arthritis involving the spine), tendinitis (inflammation of a tendon), bursitis (inflammation of a bursa, a fluid-filled sac located around joints and near the bones), and peri-arthritis of the shoulders or hips (inflammation of tissues surrounding these joints).

Benorilate is an aspirin-paracetamol ester with analgesic, antiinflammatory, and antipyretic properties. After absorption, it is rapidly metabolised to salicylate and paracetamol. It has been used orally in the treatment of mild to moderate pain and fever. It has also been used in osteoarthritis, rheumatoid arthritis, and soft-tissue rheumatism. Associated adverse reactions: nausea, diarrhea or constipation, digestive disorders or heartburn, occasionally - a transient skin rash, and sleepiness. Benoral should not be administered concomitantly with probenecid or any other uricosuric agents that decrease tubular reabsorption as any form of salicylate antagonises this effect when given in doses of less than 5 gm per day.

Tramadol (sold under the brand name Ultram) is a narcotic analgesic proposed for moderate to severe pain. Tramadol and its O-desmethyl metabolite (M1) are selective, weak OP3-receptor agonists. Opiate receptors are coupled with G-protein receptors and function as both positive and negative regulators of synaptic transmission via G-proteins that activate effector proteins. As the effector system is adenylate cyclase and cAMP located at the inner surface of the plasma membrane, opioids decrease intracellular cAMP by inhibiting adenylate cyclase. Subsequently, the release of nociceptive neurotransmitters such as substance P, GABA, dopamine, acetylcholine, and noradrenaline is inhibited. The analgesic properties of Tramadol can be attributed to norepinephrine and serotonin reuptake blockade in the CNS, which inhibits pain transmission in the spinal cord. The (+) enantiomer has the higher affinity for the OP3 receptor and preferentially inhibits serotonin uptake and enhances serotonin release. The (-) enantiomer preferentially inhibits norepinephrine reuptake by stimulating alpha(2)-adrenergic receptors. Tramadol is used primarily to treat mild-severe pain, both acute and chronic. Its analgesic effects take about one hour to come into effect and 2 h to 4 h to peak after oral administration with an immediate-release formulation. On a dose-by-dose basis, tramadol has about one-tenth the potency of morphine and is approximately equally potent when compared to pethidine and codeine. The most common adverse effects of tramadol include nausea, dizziness, dry mouth, indigestion, abdominal pain, vertigo, vomiting, constipation, drowsiness, and headache. Compared to other opioids, respiratory depression and constipation are considered less of a problem with tramadol.