PROPYLENE GLYCOL is a component of SYSTANE® Lubricant. It is used for the temporary relief of burning and irritation due to dryness of the eye.

Lidocaine is a local anesthetic and cardiac depressant used to numb tissue in a specific area and for management of cardiac arrhythmias, particularly those of ventricular origins, such as occur with acute myocardial infarction. Lidocaine alters signal conduction in neurons by blocking the fast voltage-gated Na+ channels in the neuronal cell membrane responsible for signal propagation. With sufficient blockage, the membrane of the postsynaptic neuron will not depolarize and will thus fail to transmit an action potential. This creates the anesthetic effect by not merely preventing pain signals from propagating to the brain, but by stopping them before they begin. Careful titration allows for a high degree of selectivity in the blockage of sensory neurons, whereas higher concentrations also affect other modalities of neuron signaling. Lidocaine exerts an antiarrhythmic effect by increasing the electrical stimulation threshold of the ventricle during diastole. In usual therapeutic doses, lidocaine hydrochloride produces no change in myocardial contractility, in systemic arterial pressure, or an absolute refractory period. The efficacy profile of lidocaine as a local anesthetic is characterized by a rapid onset of action and intermediate duration of efficacy. Therefore, lidocaine is suitable for infiltration, block, and surface anesthesia. Longer-acting substances such as bupivacaine are sometimes given preference for spinal and epidural anesthesias; lidocaine, though, has the advantage of a rapid onset of action. Lidocaine is also the most important class-1b antiarrhythmic drug; it is used intravenously for the treatment of ventricular arrhythmias (for acute myocardial infarction, digoxin poisoning, cardioversion, or cardiac catheterization) if amiodarone is not available or contraindicated. Lidocaine should be given for this indication after defibrillation, CPR, and vasopressors have been initiated. A routine preventative dose is no longer recommended after a myocardial infarction as the overall benefit is not convincing. Inhaled lidocaine can be used as a cough suppressor acting peripherally to reduce the cough reflex. This application can be implemented as a safety and comfort measure for patients who have to be intubated, as it reduces the incidence of coughing and any tracheal damage it might cause when emerging from anesthesia. Adverse drug reactions (ADRs) are rare when lidocaine is used as a local anesthetic and is administered correctly. Most ADRs associated with lidocaine for anesthesia relate to administration technique (resulting in systemic exposure) or pharmacological effects of anesthesia, and allergic reactions only rarely occur. Systemic exposure to excessive quantities of lidocaine mainly result in a central nervous system (CNS) and cardiovascular effects – CNS effects usually occur at lower blood plasma concentrations and additional cardiovascular effects present at higher concentrations, though cardiovascular collapse may also occur with low concentrations.

Berefrine (also known as phenylephrine oxazolidine), a prodrug of phenylephrine, is a mydriatic agent. Berefrine was developed for improving ocular absorption and reducing systemic side effects.

Caffeine is a methylxanthine alkaloid found in the seeds, nuts, or leaves of a number of plants native to South America and East Asia that is structurally related to adenosine and acts primarily as an adenosine receptor antagonist with psychotropic and anti-inflammatory activities. Upon ingestion, caffeine binds to adenosine receptors in the central nervous system (CNS), which inhibits adenosine binding. This inhibits the adenosine-mediated downregulation of CNS activity; thus, stimulating the activity of the medullary, vagal, vasomotor, and respiratory centers in the brain. The anti-inflammatory effects of caffeine are due the nonselective competitive inhibition of phosphodiesterases. Caffeine is used by mouth or rectally in combination with painkillers (such as aspirin and acetaminophen) and a chemical called ergotamine for treating migraineheadaches. It is also used with painkillers for simple headaches and preventing and treating headaches after epidural anesthesia. Caffeine creams are applied to the skin to reduce redness and itching in dermatitis. Healthcare providers sometimes give caffeine intravenously (by IV) for headache after epidural anesthesia, breathing problems in newborns, and to increase urine flow. In foods, caffeine is used as an ingredient in soft drinks, energy drinks, and other beverages.

Glycerin (glycerol) is 3-carbon alcohol naturally occurring in the human body. It is the structural backbone triacylglycerol molecules, and can also be converted to a glycolytic substrate for subsequent metabolism. Glycerin is a colorless, odorless, viscous, sweet-tasting liquid. The FDA classifies glycerol as "generally recognized as safe". Glycerin is used in the pharmaceutical industry as a sweetener in syrups, lozenges, and as an excipient in eyewash solutions. As an individual prescription product, glycerin has uses as a hyperosmotic, osmotic diuretic, and ophthalmic agent. It may be used as an eye drop in the treatment of glaucoma to reduce intraocular pressure, as a solution or suppository for short-term treatment of constipation, to evacuate the bowel prior to a colonoscopy, and in some ocular surgeries. It may be given intravenously to reduce pressure inside the brain and used externally on the skin as a moisturizer. Glycerin has many other uses in the agricultural, food and pharmaceutical industry.

Diammonium carbonate is a salt with the chemical formula (NH4)2CO3. Since it readily degrades to gaseous ammonia and carbon dioxide upon heating, it is used as a leavening agent and also as smelling salt. Ammonium carbonate may be used as a leavening agent in traditional recipes, particularly those from northern Europe and Scandinavia (e.g. Speculoos, Tunnbröd or Lebkuchen). It also serves as an acidity regulator and has the E number E503. Ammonium carbonate is the main component of smelling salts, although the commercial scale of their production is small. Buckley's cough syrup from Canada today uses ammonium carbonate as an active ingredient intended to help relieve symptoms of bronchitis. Ammonium carbonate is also used as an emetic.

Olaflur (amine fluoride 297, trade name elmex gel) is a fluoride-containing substance that is an ingredient of toothpastes and solutions for the prevention of dental caries. Especially in combination with dectaflur, it is also used in the form of gels for the treatment of early stages of caries, sensitive teeth, and by dentists for the refluoridation of damaged tooth enamel. Olaflur is a salt consisting of an alkyl ammonium cation and fluoride as the counterion. With a long lipophilic hydrocarbon chain, the cation has surfactant properties. It forms a film layer on the surface of teeth, which facilitates incorporation of fluoride into the enamel. The top layers of the enamel's primary mineral, hydroxylapatite, are converted into the more robust fluorapatite. The fluoridation reaches only a depth of a few nanometres, which has raised doubts whether the mechanism really relies on the formation of fluorapatite.

Methyl salicylate (or methyl 2-hydroxybenzoate), also known as wintergreen oil, is a natural product and is present in white wine, tea, porcini mushroom Boletus edulis, Bourbon vanilla, clary sage, red sage and fruits including cherry, apple, raspberry, papaya and plum. Methyl salicylate is topically used in combination with methanol and under brand name SALONPAS to temporarily relieves mild to moderate aches and pains of muscles and joints associated with: strains, sprains, simple backache, arthritis, bruises. The precise mechanism of action of methyl salicylate is not known, but there is suggested, that it cause dilation of the capillaries thereby increasing blood flow to the area.