Ibuprofen is a nonsteroidal anti-inflammatory agent (NSAIA) or nonsteroidal anti-inflammatory drug (NSAID), with analgesic and antipyretic properties. Ibuprofen has pharmacologic actions similar to those of other prototypical NSAIAs, which are thought to act through inhibition of prostaglandin synthesis. It’s used temporarily relieves minor aches and pains due to: headache; the common cold; muscular aches; backache; toothache; minor pain of arthritis; menstrual cramps and temporarily reduces fever. The exact mechanism of action of ibuprofen is unknown. Ibuprofen is a non-selective inhibitor of cyclooxygenase, an enzyme invovled in prostaglandin synthesis via the arachidonic acid pathway. Its pharmacological effects are believed to be due to inhibition cylooxygenase-2 (COX-2) which decreases the synthesis of prostaglandins involved in mediating inflammation, pain, fever and swelling. Antipyretic effects may be due to action on the hypothalamus, resulting in an increased peripheral blood flow, vasodilation, and subsequent heat dissipation. Inhibition of COX-1 is thought to cause some of the side effects of ibuprofen including GI ulceration. Ibuprofen is administered as a racemic mixture. The R-enantiomer undergoes extensive interconversion to the S-enantiomer in vivo. The S-enantiomer is believed to be the more pharmacologically active enantiomer.

Molindone (Moban) is a therapeutic antipsychotic, used in the treatment of schizophrenia. The exact mechanism has not been established, however, based on electroencephalogram (EEG) studies, molindone is thought to act by occupying (antagonizing) dopamine (D2) receptor sites in the reticular limbic systems in the brain, thus decreasing dopamine activity. Decreased dopamine activity results in decreased physiological effects normally induced by excessive dopamine stimulation, such as those typically seen in manifestations of psychotic disorders. The side effect profile of molindone is similar to that of other typical antipsychotics. Unlike most antipsychotics, however, molindone use is associated with weight loss.

Fenfluramine (former brand names Pondimin, Ponderax and Adifax), also known as 3-trifluoromethyl-N-ethylamphetamine, is an anorectic that is no longer marketed. In combination with phentermine, it was part of the anti-obesity medication Fen-phen. Fenfluramine was introduced on the U.S. market in 1973 and withdrawn in 1997. It is the racemic mixture of two enantiomers, dexfenfluramine, and levofenfluramine. The drug increases the level of serotonin, a neurotransmitter that regulates mood, appetite and other functions. Fenfluramine causes the release of serotonin by disrupting vesicular storage of the neurotransmitter and reversing serotonin transporter function. The drug was withdrawn from the U.S. market in 1997 after reports of heart valve disease and pulmonary hypertension, including a condition known as cardiac fibrosis. It was subsequently withdrawn from other markets around the world. In this small exploratory and retrospective study, remarkably good results were reported on the use of fenfluramine as an add-on medication for controlling seizures in patients with the Dravet syndrome. The side effects were rare and nonserious and did not result in termination of the treatment. It is possible that this drug may have anticonvulsive effects for other severe epilepsy syndromes, especially in those characterized by photosensitive or induced seizures.

Bupivacaine is a widely used local anesthetic agent. Bupivacaine is often administered by spinal injection prior to total hip arthroplasty. It is also commonly injected into surgical wound sites to reduce pain for up to 20 hours after surgery. In comparison to other local anesthetics it has a long duration of action. It is also the most toxic to the heart when administered in large doses. Bupivacaine blocks the generation and the conduction of nerve impulses, presumably by increasing the threshold for electrical excitation in the nerve, by slowing the propagation of the nerve impulse, and by reducing the rate of rise of the action potential. Bupivacaine binds to the intracellular portion of sodium channels and blocks sodium influx into nerve cells, which prevents depolarization. In general, the progression of anesthesia is related to the diameter, myelination and conduction velocity of affected nerve fibers. The analgesic effects of bupivicaine are thought to potentially be due to its binding to the prostaglandin E2 receptors, subtype EP1 (PGE2EP1), which inhibits the production of prostaglandins, thereby reducing fever, inflammation, and hyperalgesia. Bupivacaine sometimes used in combination with epinephrine to prevent systemic absorption and extend the duration of action.

Clorazepate is a water-soluble benzodiazepine derivative effective in the treatment of anxiety. It has also muscle relaxant and anticonvulsant actions. Studies in healthy men have shown that clorazepate dipotassium has depressant effects on the central nervous system. clorazepate is a prodrug since orally administered it is rapidly decarboxylated to form nordiazepam, there is essentially no circulating parent drug. Nordiazepam positively modulates GABAA receptors to produce anxiolytic and anticonvulsant effects.

Hydromorphone (also known as dihydromorphinone and the brand name Dilaudid among others) is a more potent opioid analgesic than morphine and is used for moderate to severe pain. It can be administered by injection, by infusion, by mouth, and rectally. Oral bioavailability is low. The kidney excretes hydromorphone and its metabolites. Some metabolites may have greater analgesic activity than hydromorphone itself but are unlikely to contribute to the pharmacological activity of hydromorphone. With the exception of pruritus, sedation and nausea and vomiting, which may occur less after hydromorphone than after morphine, the side-effects of these drugs are similar. Hydromorphone interacts predominantly with the opioid mu-receptors. These mu-binding sites are discretely distributed in the human brain, with high densities in the posterior amygdala, hypothalamus, thalamus, nucleus caudatus, putamen, and certain cortical areas. It also binds with kappa and delta receptors which are thought to mediate spinal analgesia, miosis and sedation.

Naloxone, sold under the brand name Narcan among others, is a medication used to block the effects of opioids, especially in overdose. Naloxone has an extremely high affinity for μ-opioid receptors in the central nervous system (CNS). Naloxone is a μ-opioid receptor (MOR) inverse agonist, and its rapid blockade of those receptors often produces rapid onset of withdrawal symptoms. Naloxone also has an antagonist action, though with a lower affinity, at κ- (KOR) and δ-opioid receptors (DOR). If administered in the absence of concomitant opioid use, no functional pharmacological activity occurs (except the inability for the body to combat pain naturally). In contrast to direct opiate agonists, which elicit opiate withdrawal symptoms when discontinued in opiate-tolerant people, no evidence indicates the development of tolerance or dependence on naloxone. The mechanism of action is not completely understood, but studies suggest it functions to produce withdrawal symptoms by competing for opiate receptor sites within the CNS (a competitive antagonist, not a direct agonist), thereby preventing the action of both endogenous and xenobiotic opiates on these receptors without directly producing any effects itself. When administered parenterally (e.g. intravenously or by injection), as is most common, naloxone has a rapid distribution throughout the body. The mean serum half-life has been shown to range from 30 to 81 minutes, shorter than the average half-life of some opiates, necessitating repeat dosing if opioid receptors must be stopped from triggering for an extended period. Naloxone is primarily metabolized by the liver. Its major metabolite is naloxone-3-glucuronide, which is excreted in the urine. Naloxone is useful both in acute opioid overdose and in reducing respiratory or mental depression due to opioids. Whether it is useful in those in cardiac arrest due to an opioid overdose is unclear. Naloxone is poorly absorbed when taken by mouth, so it is commonly combined with a number of oral opioid preparations, including buprenorphine and pentazocine, so that when taken orally, just the opioid has an effect, but if misused by injecting, the naloxone blocks the effect of the opioid. In a meta-analysis of people with shock, including septic, cardiogenic, hemorrhagic, or spinal shock, those who received naloxone had improved blood flow. Naloxone is also experimentally used in the treatment for congenital insensitivity to pain with anhidrosis, an extremely rare disorder (one in 125 million) that renders one unable to feel pain or differentiate temperatures. Naloxone can also be used as an antidote in overdose of clonidine, a medication that lowers blood pressure.

Flavoxate is a drug, indicated for symptomatic relief of dysuria, urgency, nocturia, suprapubic pain, frequency and incontinence as may occur in cystitis, prostatitis, urethritis, urethrocystitis/urethrotrigonitis. Flavoxate is not indicated for definitive treatment, but is compatible with drugs used for the treatment of urinary tract infections. It was approved for use in the United States in 1970 and continues to be used. Drug acts as a direct antagonist at muscarinic acetylcholine receptors in cholinergically innervated organs. Its anticholinergic-parasympatholytic action reduces the tonus of smooth muscle in the bladder, effectively reducing the number of required voids, facilitating increased volume per void. Common side effects are those of parasympathetic stimulation and include dryness of the mouth and eyes, decreased sweating, headache, visual blurring, constipation, urinary retention, impotence, tachycardia and palpitations, anxiety, restlessness and in some instances agitation and delusions.

Levodopa (L-DOPA) was first isolated from seedlings of Vicia faba by Marcus Guggenheim in 1913. Levodopa, a dopamine precursor, is an effective and well-tolerated dopamine replacement agent used to treat Parkinson's disease. Oral levodopa has been widely used for over 40 years, often in combination with a dopa-decarboxylase inhibitor carbidopa, which reduces many treatment complications, extending its half-life and increasing levodopa availability to the brain. Entacapone, a catechol-O-methyltransferase inhibitor, can also be used to improve the bioavailability of levodopa, especially when used in conjunction with a carbidopa.

Ketamine (brand name Ketalar) is a cyclohexanone derivative used for induction of anesthesia. Ketalar is indicated as the sole anesthetic agent for diagnostic and surgical procedures that do not require skeletal muscle relaxation; also, it is indicated for the induction of anesthesia prior to the administration of other general anesthetic agents. Ketamine blocks NMDA receptors through an interaction with sites thought to be located within the ion channel pore region. However, the complete pharmacology of ketamine is more complex, and it is known to directly interact with a variety of other sites to varying degrees. Recently, it was shown that inclusion of the NR3B subunit does not alter the ketamine sensitivity of recombinant NR1/NR2 receptors expressed in oocytes. Likewise, 100 μM ketamine produced only weak inhibition of the glycine-induced current of NR1/NR3A/NR3B receptors. The side effects of ketamine noted in clinical studies include psychedelic symptoms (hallucinations, memory defects, panic attacks), nausea/vomiting, somnolence, cardiovascular stimulation and, in a minority of patients, hepatoxicity. The recreational use of ketamine is increasing and comes with a variety of additional risks ranging from bladder and renal complications to persistent psychotypical behaviour and memory defects. Ketamine was first synthesized in 1962 by Calvin Stevens at Parke-Davis Co (now Pfizer) as an alternative anesthetic to phencyclidine. It was first used in humans in 1965 by Corssen and Domino and was introduced into clinical practice by 1970.