Oxygen is a chemical element with atomic number 8. Diatomic oxygen constitutes 20.8% of the Earth's atmosphere. Diatomic oxygen is used by complex life forms such as animals, in cellular respiration. Medical oxygen is widely used in clinical practice to provide a basis for most modern anaesthetic techniques; to restore the tissue oxygen tension towards normal by improving oxygen availability in a wide range of conditions such as shock, severe haemorrhage, coronary occlusion, carbon monoxide poisoning, major trauma; to aid the resuscitation of the critically ill, when the circulation is impaired; to aid in neonatal resuscitation; to treat acute severe headache in adults diagnosed with cluster headache.

Cocaine is an alkaloid ester extracted from the leaves of plants including coca. Cocaine is a local anesthetic and vasoconstrictor and is clinically used for that purpose, particularly in the eye, ear, nose, and throat. It also has powerful central nervous system effects similar to the amphetamines and is a drug of abuse. Cocaine, like amphetamines, acts by multiple mechanisms on brain catecholaminergic neurons; the mechanism of its reinforcing effects is thought to involve inhibition of dopamine uptake. Cocaine is addictive due to its effect on the reward pathway in the brain. After a short period of use, there is a high risk that dependence will occur. Its use also increases the risk of stroke, myocardial infarction, lung problems in those who smoke it, blood infections, and sudden cardiac death. Cocaine sold on the street is commonly mixed with local anesthetics, cornstarch, quinine, or sugar which can result in additional toxicity. Following repeated doses, a person may have decreased the ability to feel pleasure and be very physically tired. Cocaine acts by inhibiting the reuptake of serotonin, norepinephrine, and dopamine. This results in greater concentrations of these three neurotransmitters in the brain. It can easily cross the blood-brain barrier and may lead to the breakdown of the barrier.

Nitrous oxide (N2O, laughing gas) was first discovered by the English scientist Joseph Priestly and has been used for more than 150 years. It has remained one of the most widely used anesthetics in both dental and medical applications. This small and simple inorganic chemical molecule has indisputable effects of analgesia, anxiolysis, and anesthesia that are of great clinical interest. As a general anesthetic, it is very weak and is generally not used as a single agent. It may be used as a carrier gas with oxygen in combination with more potent general inhalational gases for surgical anesthesia. In dentistry, it is commonly used as a single agent (with oxygen) for partial sedation, most commonly in pediatric dental populations. Findings to date indicate that the analgesic effect of N2O is opioid in nature, and, like morphine, may involve a myriad of neuromodulators in the spinal cord. The anxiolytic effect of N2O, on the other hand, resembles that of benzodiazepines and may be initiated at selected subunits of the gamma-aminobutyric acid type A (GABA(A)) receptor. Similarly, the anesthetic effect of N2O may involve actions at GABA(A) receptors and possibly at N-methyl-D-aspartate receptors as well.

Morphine is one of the most important and widely used opioid for the treatment of chronic and acute pain: the very wide interindividual variability in the patients’ response to the drug may have genetic derivations. Sulphate salt of morphine sold under the many brand names, one of them, DURAMORPH, which is indicated for the management of pain severe enough to require use of an opioid analgesic by intravenous administration, and for which alternative treatments are not expected to be adequate. In addition for the epidural or intrathecal management of pain without attendant loss of motor, sensory, or sympathetic function. Morphine is a full opioid agonist and is relatively selective for the mu-opioid receptor, although it can bind to other opioid receptors at higher doses. The principal therapeutic action of morphine is analgesia. Like all full opioid agonists, there is no ceiling effect for analgesia with morphine. The precise mechanism of the analgesic action is unknown. However, specific CNS opioid receptors for endogenous compounds with opioid-like activity have been identified throughout the brain and spinal cord and are thought to play a role in the analgesic effects of this drug. Morphine has a high potential for addiction and abuse. Common side effects include drowsiness, vomiting, and constipation. Caution is advised when used during pregnancy or breast-feeding, as morphine will affect the baby.

Alcohols exhibit rapid broad-spectrum antimicrobial activity against vegetative bacteria (including mycobacteria), viruses, and fungi but are not sporicidal. They are, however, known to inhibit sporulation and spore germination, but this effect is reversible. Because of the lack of sporicidal activity, alcohols are not recommended for sterilization but are widely used for both hard-surface disinfection and skin antisepsis. Lower concentrations may also be used as preservatives and to potentiate the activity of other biocides. Many alcohol products include low levels of other biocides (in particular chlorhexidine), which remain on the skin following evaporation of the alcohol, or excipients (including emollients), which decrease the evaporation time of the alcohol and can significantly increase product efficacy. Ethanol in combination with: chlorhexidine gluconate 1% was approved to use in surgical hand antiseptic. It significantly reduces the number of microorganisms on the hands and forearms prior to surgery or patient care. Ethanol is also used as a co-solvent to dissolve many insoluble drugs and to serve as a mild sedative in some medicinal formulations. Ethanol is metabolized by the hepatic enzyme alcohol dehydrogenase. Ethanol affects the brain’s neurons in several ways. It alters their membranes as well as their ion channels, enzymes, and receptors. Alcohol also binds directly to the receptors for acetylcholine, serotonin, GABA, and the NMDA receptors for glutamate. The sedative effects of ethanol are mediated through binding to GABA receptors and glycine receptors (alpha 1 and alpha 2 subunits). It also inhibits NMDA receptor functioning. In its role as an anti-infective, ethanol acts as an osmolyte or dehydrating agent that disrupts the osmotic balance across cell membranes.

Benzoyl peroxide (BPO) is an organic compound in the peroxide family. It consists of two benzoyl groups bridged by a peroxide link. It is one of the most important organic peroxides in terms of applications and the scale of its production. Benzoyl peroxide is used as an acne treatment, for bleaching hair and teeth. Adverse reactions are: dryness and urticarial reaction, contact dermatitis, application site burning, application site irritation and skin irritation.

Clotrimazole is an anti-fungal medicine indicated for the treatment of vaginal yeast infections and tinea. It can be used either in combination with other drugs (betamethasone dipropionate) or alone, in form of topical or vaginal cream. The drug exerts its action by inhibiting lanosterol demethylase thereby affecting the growth of fungi.

Miconazole is a synthetic imidazole derivative, a topical antifungal agent for use in the local treatment of vaginal, and skin and nail infections due to yeasts and dermatophytes. It is particularly active against Candida spp., Trichophyton spp., Epidermophyton spp., Microsporum spp. and Pityrosporon orbiculare (Malassezia furfur), but also possesses some activity against Gram-positive bacteria. It binds to the heme moiety of the fungal cytochrome P-450 dependent enzyme lanosterol 14-alpha-demethlyase. Inhibits 14-alpha-demethlyase, blocks formation of ergosterol and leads to the buildup of toxic methylated 14-a-sterols. Miconazole also affects the synthesis of triglycerides and fatty acids and inhibits oxidative and peroxidative enzymes, increasing the amount of active oxygen species within the cell.

Pyrantel is an anthelmintic, which acts as an agonist of nicotinic receptors (AChRs) of nematodes and exerts its therapeutic effects by depolarizing their muscle membranes. It is used to treat a number of parasitic worm infections. This includes ascariasis, hookworm infections, enterobiasis (pinworm infection), trichostrongyliasis and trichinellosis. Common adverse reactions include diarrhea, nausea, vomiting, dizziness, headache and somnolence.

Haloprogin is an active synthetic antifungal and antimonilial agent that was effective in the treatment of superficial fungal and monilial infections of the skin. Because of these two basic therapeutic effects, haloprogin was especially useful in the treatment of infections when the identity of the specific causative organism had not been established or is being determined. Studies in-vitro demonstrated antifungal, antimonilial and antibacterial activity. It was shown to demonstrate marked in-vitro activity against Staphylococcus and Streptococcus. Haloprogin is no longer available in the US.