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.

Tetracaine (INN, also known as amethocaine; trade name Pontocaine. Ametop and Dicaine) is a potent local anesthetic of the ester group. It is mainly used topically in ophthalmology and as an antipruritic, and it has been used in spinal anesthesia. Tetracaine blocks sodium ion channels required for the initiation and conduction of neuronal impulses thereby affecting local anesthesia. In biomedical research, tetracaine is used to alter the function of calcium release channels (ryanodine receptors) that control the release of calcium from intracellular stores. Tetracaine is an allosteric blocker of channel function. At low concentrations, tetracaine causes an initial inhibition of spontaneous calcium release events, while at high concentrations, tetracaine blocks release completely.

Dibucaine is used as a local anesthetic for surface anesthesia. It is one of the most potent and toxic of the long-acting local anesthetics and its parenteral use is restricted to spinal anesthesia. Dibucaine is used to temporarily relieve pain and itching due to: hemorrhoids or other anorectal disorders, sunburn, minor burns, minor cuts; scrapes, insect bites, minor skin irritation. This drug acts via blocking of nerve impulses by decreasing the neuronal membrane's permeability to sodium ions through sodium channel blocking. This reversibly stabilizes the membrane and inhibits depolarization, resulting in the failure of a propagated action potential and subsequent conduction blockade.

Ephedrine (l-form) is an alkaloid, which was initially purified from Ephedra plant. The extract form Ephedra has been used in China for medicinal purposes for several thousand years. Ephedrine acts as an agonist at alpha- and beta-adrenergic receptors and indirectly causes the release of norepinephrine from sympathetic neurons. The drug crosses the blood brain barrier and stimulates the central nervous system. Ephedrine products are now banned in many countries, as they are a major source for the production of the addictive compound methamphetamine. FDA has approved ephedrine only for the treatment of clinically important hypotension occurring in the setting of anesthesia.

Camphor is a bicyclic monoterpene ketone found widely in plants, especially cinnamomum camphora. Topically, camphor is used to relieve pain. It has been used to treat warts, cold sores, hemorrhoids, and osteoarthritis. It has also been applied topically as an analgesic and an antipruritic. It has been used as a counterirritant, and to increase local blood flow. Camphor has frequently been used topically to treat respiratory tract diseases involving mucous membrane inflammation. It is sometimes used topically to treat cardiac symptoms. Camphor is also used topically as an eardrop, and for treating minor burns. In inhalation therapy, camphor is used as an antitussive. Orally, camphor is used as an expectorant, antiflatulent, and for treating respiratory tract diseases. Today, most camphor is synthetic. It is approved by the FDA as a topical antitussive. Camphor is produced synthetically from the oil of turpentine. It has been used for centuries for its medicinal features, in religious rituals, and in cooking. It is no longer used as pesticide. In 1982, the US Food and Drug Administration restricted commercial products intended for medicinal use to contain <11% camphor.

Benzocaine is a local anesthetic. It acts by blocking voltage-gated sodium ion channels in nerve endings. Benzocaine is available over-the counter for local anesthesia of oral and pharyngeal mucous membranes (sore throat, cold sores, mouth ulcers, toothache, sore gums, denture irritation), otic pain, and as a local anesthetic for surgical or diagnostic procedures. As a spray, benzocaine is used for temporary relief of pain and itching associated with minor burns, sunburn, minor cuts or scrapes, insect bites, or minor skin irritations. Topical application of benzocaine to gums or mouth may cause rare, but serious and potentially fatal adverse effect methemoglobinemia.

Phenol is an industrially important organic compound, produced on a large scale and used as a precursor to many materials and useful compounds. Phenol and its vapors are corrosive to the eyes, the skin, and the respiratory tract. The corrosive effect on skin and mucous membranes is due to a protein-degenerating effect. In medicine, phenol is used as an antiseptic and disinfectant. Phenol is also used as an oral analgesic or anesthetic in products such as Chloraseptic to treat sore throat pain, sore mouth, pain associated with canker sores and minor mouth irritation. Additionally, phenol and its related compounds are used in surgical ingrown toenail treatment, a process termed phenolization.

Eprosartan is an angiotensin II receptor antagonist used for the treatment of high blood pressure. It acts on the renin-angiotensin system in two ways to decrease total peripheral resistance. First, it blocks the binding of angiotensin II to AT1 receptors in vascular smooth muscle, causing vascular dilatation. Second, it inhibits sympathetic norepinephrine production, further reducing blood pressure. Eprosartan is indicated for the management of hypertension alone or in combination with other classes of antihypertensive agents. Also used as a first-line agent in the treatment of diabetic nephropathy, as well as a second-line agent in the treatment of congestive heart failure (only in those intolerant of ACE inhibitors).

Arbutamine was indicated to elicit acute cardiovascular responses in order to aid in diagnosing the presence or absence of coronary artery disease in patients who cannot exercise adequately. Arbutamine is a synthetic catecholamine with positive chronotropic and inotropic properties. The chronotropic (increase in heart rate [HR]) and inotropic (increase in force of contraction) effects of arbutamine serve to mimic exercise by increasing cardiac work (producing stress) and provoke myocardial ischemia in patients with compromised coronary arteries. In functional assays, arbutamine is more selective for beta-adrenergic receptors than for alpha-adrenergic receptors. The beta-agonist activity of arbutamine provides cardiac stress by increasing HR, cardiac contractility, and systolic blood pressure.

Flosequinan is a vasodilator developed for the treatment of heart failure. The drug was marketed under the name Manoplax, however it was withdrawn by the FDA decision since it increased congestive heart failure symptoms. The exact mechanism of flosequinan action is unknown, but there are studies reporting the inhibition of PDE3 activity.