Diflunisal is a salicylic acid derivative with analgesic and anti-inflammatory activity. It was developed by Merck Sharp & Dohme in 1971 after showing promise in a research project studying more potent chemical analogs of aspirin. Diflunisal is an aspirin-like nonsteroidal anti-inflammatory drug that inhibits cyclooxygenase-2 (COX-2), an enzyme involved in prostaglandin synthesis.In animals, prostaglandins sensitize afferent nerves and potentiate the action of bradykinin in inducing pain. Since prostaglandins are known to be among the mediators of pain and inflammation, the mode of action of diflunisal may be due to a decrease of prostaglandins in peripheral tissues.

Buprenorphine is an opioid analgesic, used to treat opioid addiction, moderate acute pain, and moderate chronic pain. Buprenorphine is a partial agonist at the mµ-opioid receptor and an antagonist at the kappa-opioid receptor. One unusual property of buprenorphine observed in vitro studies is its very slow rate of dissociation from its receptor. This could account for its longer duration of action than morphine, the unpredictability of its reversal by opioid antagonists, and its low level of manifest physical dependence. The principal action of the therapeutic value of buprenorphine is analgesia and is thought to be due to buprenorphine binding with high affinity to opioid receptors on neurons in the brain and spinal cord. Buprenorphine produces respiratory depression by direct action on brain stem respiratory centers. The respiratory depression involves a reduction in the responsiveness of the brain stem respiratory centers to both increases in carbon dioxide tension and electrical stimulation. Buprenorphine causes a reduction in motility associated with an increase in smooth muscle tone in the antrum of the stomach and duodenum. Digestion of food in the small intestine is delayed and propulsive contractions are decreased. Buprenorphine produces peripheral vasodilation, which may result in orthostatic hypotension or syncope. Manifestations of histamine release and/or peripheral vasodilation may include pruritus, flushing, red eyes, sweating, and/or orthostatic hypotension.

Meclofenamic acid, used as Meclofenamate sodium, is a non-steroidal anti-inflammatory agent with antipyretic and antigranulation activities. Meclofenamate sodium capsules are indicated for the relief of mild to moderate pain, for the treatment of primary dysmenorrhea and for the treatment of idiopathic heavy menstrual blood loss; for relief of signs and symptoms of juvenile arthritis; so as for relief of the signs and symptoms of rheumatoid arthritis; For relief of the signs and symptoms of osteoarthritis. The mode of action, like that of other nonsteroidal anti-inflammatory agents, is not known. Therapeutic action does not result from pituitary-adrenal stimulation. In animal studies, meclofenamate sodium was found to inhibit prostaglandin synthesis and to compete for binding at the prostaglandin receptor site. In vitro, meclofenamate sodium was found to be an inhibitor of human leukocyte 5-lipoxygenase activity. These properties may be responsible for the anti-inflammatory action of meclofenamate sodium. There is no evidence that meclofenamate sodium alters the course of the underlying disease.

Sulindac is a nonsteroidal anti-inflammatory agent (NSAIA) of the arylalkanoic acid class that is marketed in the U.S. by Merck as Clinoril. Like other NSAIAs, it may be used in the treatment of acute or chronic inflammatory conditions. Sulindac is a prodrug, derived from sulfinylindene, that is converted in vivo to an active sulfide compound by liver enzymes. The sulfide metabolite then undergoes enterohepatic circulation; it is excreted in the bile and then reabsorbed from the intestine. This is thought to help maintain constant blood levels with reduced gastrointestinal side effects. Some studies have shown sulindac to be relatively less irritating to the stomach than other NSAIA's except for drugs of the cyclooxygenase-2 (COX-2) inhibitor class. The exact mechanism of its NSAIA properties is unknown, but it is thought to act on enzymes COX-1 and COX-2, inhibiting prostaglandin synthesis.

Naproxen (naproxen sodium, NAPROSYN®) is a propionic acid derivative related to the arylacetic acid group of nonsteroidal anti-inflammatory drugs (NSAIDs). It is an anti-inflammatory agent with analgesic and antipyretic properties. Both the acid and its sodium salt are used in the treatment of rheumatoid arthritis and other rheumatic or musculoskeletal disorders, dysmenorrhea, and acute gout. The mechanism of action of the naproxen (naproxen sodium, NAPROSYN®), like that of other NSAIDs, is not completely understood but involves inhibition of cyclooxygenase (COX-1 and COX-2).

Fenoprofen is a propionic acid derivative with analgesic, antiinflammatory and antipyretic properties. Fenoprofen inhibits prostaglandin synthesis by decreasing the enzyme needed for biosynthesis. In patients with rheumatoid arthritis, the anti-inflammatory action of fenoprofen has been evidenced by relief of pain, increase in grip strength, and reductions in joint swelling, duration of morning stiffness, and disease activity (as assessed by both the investigator and the patient). In patients with osteoarthritis, the anti-inflammatory and analgesic effects of fenoprofen have been demonstrated by reduction in tenderness as a response to pressure and reductions in night pain, stiffness, swelling, and overall disease activity (as assessed by both the patient and the investigator). These effects have also been demonstrated by relief of pain with motion and at rest and increased range of motion in involved joints. In patients with rheumatoid arthritis and osteoarthritis, clinical studies have shown fenoprofen to be comparable to aspirin in controlling the aforementioned measures of disease activity, but mild gastrointestinal reactions (nausea, dyspepsia) and tinnitus occurred less frequently in patients treated with fenoprofen than in aspirin-treated patients. It is not known whether fenoprofen causes less peptic ulceration than does aspirin. In patients with pain, the analgesic action of fenoprofen has produced a reduction in pain intensity, an increase in pain relief, improvement in total analgesia scores, and a sustained analgesic effect. Indicated for relief of the signs and symptoms of rheumatoid arthritis and osteoarthritis. Also for the relief of mild to moderate pain.

Tolmetin is a nonsteroidal anti-inflammatory agent. It was marketed as Tolectin in USA. TOLECTIN (tolmetin sodium) is indicated for the relief of signs and symptoms of rheumatoid arthritis and osteoarthritis. TOLECTIN is indicated in the treatment of acute flares and the long-term management of the chronic disease. TOLECTIN is also indicated for treatment of juvenile rheumatoid arthritis. The mode of action of tolmetin is not known. However, studies in laboratory animals and man have demonstrated that the anti-inflammatory action of tolmetin is not due to pituitary-adrenal stimulation. Tolmetin inhibits prostaglandin synthetase in vitro and lowers the plasma level of prostaglandin E in man. This reduction in prostaglandin synthesis may be responsible for the anti-inflammatory action.

Indometacin (INN and BAN) or indomethacin (AAN, USAN, and former BAN) is a nonsteroidal anti-inflammatory drug (NSAID) commonly used as a prescription medication to reduce fever, pain, stiffness, and swelling from inflammation. Indomethacin has analgesic, anti-inflammatory, and antipyretic properties. The mechanism of action of Indometacin, like that of other NSAIDs, is not completely understood but involves inhibition of cyclooxygenase (COX-1 and COX-2). Indomethacin is a potent inhibitor of prostaglandin synthesis in vitro. Indomethacin concentrations reached during therapy have produced in vivo effects. Prostaglandins sensitize afferent nerves and potentiate the action of bradykinin in inducing pain in animal models. Prostaglandins are mediators of inflammation. Because indomethacin is an inhibitor of prostaglandin synthesis, its mode of action may be due to a decrease of prostaglandins in peripheral tissues. Indometacin is indicated for: Moderate to severe rheumatoid arthritis including acute flares of chronic disease, Moderate to severe ankylosing spondylitis, Moderate to severe osteoarthritis, Acute painful shoulder (bursitis and/or tendinitis), Acute gouty arthritis. In general, adverse effects seen with indomethacin are similar to all other NSAIDs. For instance, indometacin inhibits both cyclooxygenase-1 and cyclooxygenase-2, it inhibits the production of prostaglandins in the stomach and intestines, which maintain the mucous lining of the gastrointestinal tract. Indometacin, therefore, like other non-selective COX inhibitors can cause peptic ulcers. These ulcers can result in serious bleeding and/or perforation requiring hospitalization of the patient. To reduce the possibility of peptic ulcers, indomethacin should be prescribed at the lowest dosage needed to achieve a therapeutic effect, usually between 50–200 mg/day. It should always be taken with food. Nearly all patients benefit from an ulcer protective drug (e.g. highly dosed antacids, ranitidine 150 mg at bedtime, or omeprazole 20 mg at bedtime). Other common gastrointestinal complaints, including dyspepsia, heartburn and mild diarrhea are less serious and rarely require discontinuation of indomethacin.

Oxycodone is a semisynthetic opioid used for the management of acute and chronic pain severe enough to require an opioid analgesic and for which alternative treatments are inadequate. Oxycodone is a highly selective full agonist of the μ-opioid receptor (MOR), with low affinity for the δ-opioid receptor (DOR) and κ-opioid receptor (KOR). After oxycodone binds to the MOR, a G protein-complex is released, which inhibits the release of neurotransmitters by the cell by reducing the amount of cAMP produced, closing calcium channels, and opening potassium channels. After a dose of conventional (instant-release) oral oxycodone, the onset of action is 10–30 minutes, and peak plasma levels of the drug are attained within roughly 30–60 minutes in contrast, after a dose of OxyContin (an oral controlled-release formulation), peak plasma levels of oxycodone occur in about three hours. The duration of instant-release oxycodone is 3 to 6 hours, although this can be variable depending on the individual. Oxycodone in the blood is distributed to skeletal muscle, liver, intestinal tract, lungs, spleen, and brain. Serious side effects of oxycodone include reduced sensitivity to pain (beyond the pain the drug is taken to reduce), euphoria, anxiolysis, feelings of relaxation, and respiratory depression. Common side effects of oxycodone include constipation (23%), nausea (23%), vomiting (12%), somnolence (23%), dizziness (13%), itching (13%), dry mouth (6%), and sweating (5%).

Adelmidrol is the synthetic derivate of azelaic acid, a naturally occurring saturated dicarboxylic acid, that is found in some whole grains and in trace amounts in the human body. Chemically, ademidrol is the N,N-bis (2-hydroxyethyl) non anediamide and it is an amphiphilic or amphipathic compound, possessing both hydrophilic and hydrophobic properties, that favor its solubility both in aqueous and organic media. Adelmidrol belongs to the aliamide family, a group of fatty acid derivatives with cannabimimetic properties, able to control mast cell (MC) hyperreactivity in several pathophysiological and pathological conditions. Pro-inflammatory NF-κB pathway were markedly reduced by treatment with adelmidrol. The anti-inflammatory effect of adelmidrol appeared to be related on PPAR-gamma activation. Adelmidrol is topically effective for human inflammatory skin disorders and is able to modulate the inflammatory response in human keratinocytes. The combination of hyaluronic acid and adelmidrol improves the signs of osteoarthritis induced by monosodium iodoacetate.