Quinidine is a pharmaceutical agent that acts as a class I antiarrhythmic agent (Ia) in the heart. It is a stereoisomer of quinine, originally derived from the bark of the cinchona tree. The drug causes increased action potential duration, as well as a prolonged QT interval. Like all other class I antiarrhythmic agents, quinidine primarily works by blocking the fast inward sodium current (INa). Quinidine's effect on INa is known as a 'use-dependent block'. This means at higher heart rates, the block increases, while at lower heart rates, the block decreases. The effect of blocking the fast inward sodium current causes the phase 0 depolarization of the cardiac action potential to decrease (decreased Vmax). Quinidine also blocks the slowly inactivating, tetrodotoxin-sensitive Na current, the slow inward calcium current (ICA), the rapid (IKr) and slow (IKs) components of the delayed potassium rectifier current, the inward potassium rectifier current (IKI), the ATP-sensitive potassium channel (IKATP) and Ito. Quinidine is also an inhibitor of the cytochrome P450 enzyme 2D6 and can lead to increased blood levels of lidocaine, beta blockers, opioids, and some antidepressants. Quinidine also inhibits the transport protein P-glycoprotein and so can cause some peripherally acting drugs such as loperamide to have central nervous system side effects, such as respiratory depression if the two drugs are coadministered. Quinidine can cause thrombocytopenia, granulomatous hepatitis, myasthenia gravis, and torsades de pointes, so is not used much today. Torsades can occur after the first dose. Quinidine-induced thrombocytopenia (low platelet count) is mediated by the immune system and may lead to thrombocytic purpura. A combination of dextromethorphan and quinidine has been shown to alleviate symptoms of easy laughing and crying (pseudobulbar affect) in patients with amyotrophic lateral sclerosis and multiple sclerosis. This drug is marketed as Nuedexta in the United States. Intravenous quinidine is also indicated for the treatment of Plasmodium falciparum malaria. However, quinidine is not considered the first-line therapy for P. falciparum. The recommended treatments for P. falciparum malaria, according to the Toronto Notes 2008, are a combination of either quinine and doxycycline or atovaquone and proguanil (Malarone). The drug is also effective for the treatment of atrial fibrillation in horses.

Quinine soluble salts possess the extremely bitter taste, that may have a perplexing problem especially to children. That is why the most common combinations which are administered in this way are the sulphate, salicylate, tannate and certain esters. Quinine tannate, an insoluble quinine salt has been known in medicine for a very long time. However, many experiments have revealed that quinine tannate was practically inert as a medicinal substance.

Atropine inhibits the muscarinic actions of acetylcholine on structures innervated by postganglionic cholinergic nerves, and on smooth muscles which respond to endogenous acetylcholine but are not so innervated. As with other antimuscarinic agents, the major action of atropine is a competitive or surmountable antagonism which can be overcome by increasing the concentration of acetylcholine at receptor sites of the effector organ (e.g., by using anticholinesterase agents which inhibit the enzymatic destruction of acetylcholine). The receptors antagonized by atropine are the peripheral structures that are stimulated or inhibited by muscarine (i.e., exocrine glands and smooth and cardiac muscle). Responses to postganglionic cholinergic nerve stimulation also may be inhibited by atropine but this occurs less readily than with responses to injected (exogenous) choline esters. Atropine is relatively selective for muscarinic receptors. Its potency at nicotinic receptors is much lower, and actions at non-muscarinic receptors are generally undetectable clinically. Atropine does not distinguish among the M1, M2, and M3 subgroups of muscarinic receptors.

Colchicine is an alkaloid obtained from the plant colchicum autumnale (also known as "meadow saffron"). Colchicine is an alternative medication for those unable to tolerate NSAIDs in gout. Mechanism of action of colchicine is inhibition of microtubule polymerization by binding to tubulin. Availability of tubulin is essential to mitosis, so colchicine effectively unctions as a "mitotic poison" or spindle poison.

Nitrite Ion is a symmetric anion with equal N–O bond lengths. Nitrite is important in biochemistry as a source of the potent vasodilator nitric oxide. Nitrate or nitrite (ingested) under conditions that result in endogenous nitrosation has been classified as "Probably carcinogenic to humans" (Group 2A) by International Agency for Research on Cancer (IARC), the specialized cancer agency of the World Health Organization (WHO) of the United Nations. Sodium nitrite is used for the curing of meat because it prevents bacterial growth and, as it is a reducing agent (opposite of oxidation agent), in a reaction with the meat's myoglobin, gives the product a desirable pink-red "fresh" color, such as with corned beef. This use of nitrite goes back to the Middle Ages, and in the US has been formally used since 1925. Because of the relatively high toxicity of nitrite (the lethal dose in humans is about 22 milligrams per kilogram of body weight), the maximum allowed nitrite concentration in meat products is 200 ppm. At these levels, some 80 to 90% of the nitrite in the average U.S. diet is not from cured meat products, but from natural nitrite production from vegetable nitrate intake. Under certain conditions – especially during cooking – nitrites in meat can react with degradation products of amino acids, forming nitrosamines, which are known carcinogens. However, the role of nitrites (and to some extent nitrates) in preventing botulism by preventing C. botulinum endospores from germinating have prevented the complete removal of nitrites from cured meat, and indeed by definition in the U.S., meat cannot be labeled as "cured" without nitrite addition. They are considered irreplaceable in the prevention of botulinum poisoning from consumption of cured dry sausages by preventing spore germination. Nitrite is a member of the drug class antidotes and is used to treat Cyanide Poisoning.

Benzoic acid is a natural ingredient occurring in many foodstuffs and in plant extracts. Benzoic acid, its salts and esters are used as preservatives in cosmetic products, with a maximum concentration of 0.5 %. Benzoic acid and sodium benzoate are on the FDA list of substances that are generally recognized as safe (GRAS). Both may be used as antimicrobial agents, flavouring agents and as adjuvants with a current maximum level of 0.1% in food. Benzoic acid is a constituent of Whitfield Ointment, which is used for the treatment of fungal skin diseases such as tinea, ringworm, and athlete's foot. Adverse effect of Whitfield Ointment: occasionally, a localized mild inflammatory response occurs.

Methylene blue, also known as methylthioninium chloride, is a medication from WHO's list of essential medicines. Upon administration, methylene blue is converted to leukomethylene blue by erythrocyte methemoblobin reductase in the presence of NADPH. Leukomethylene blue than reduces methemoglobin to oxyhemoglobin, thus restoring oxygen carrying capacity of the blood. Methylene blue is also used as a dye for various diagnostic procedures, for treatment of ifosfamide toxicity and for in vitro staining. Historically, it was used as a photosensitizer for photodynamic therapy for topical treatment of dermatologic or mucocutaneous infections, as an antidote for cyanide poisoning, but these applications are no longer approved. Methylene blue is investigated in clinical trials for treatment of septic shock and Alzheimer's disease.

There is no information about biological and pharmacological application of Iron(II) fluoride (also known as ferrous fluoride). It is known, that this substance is used to catalyze some organic reactions.

Sodium thiosulfate (sodium thiosulphate/STS) is a chemical and medication. As a medication, it is used in combination with sodium nitrite under the trade name to NITHIODOTE treat cyanide poisoning. The primary route of endogenous cyanide detoxification is by enzymatic transulfuration to thiocyanate (SCN- ), which is relatively nontoxic and readily excreted in the urine. Sodium thiosulfate is thought to serve as a sulfur donor in the reaction catalyzed by the enzyme rhodanese, thus enhancing the endogenous detoxification of cyanide. In addition, Sodium thiosulfate is used in calciphylaxis in hemodialysis patients with end-stage kidney disease. Calciphylaxis is vasculopathy characterized by ischemia and painful skin necrosis due to calcification and intimal fibroplasia of thrombosis of the panicular arterioles. Sodium thiosulfate is used as treatment due to its antioxidant activity and as a chelating. Sodium thiosulfate renders renal protection by modulating the mitochondrial KATP channel for preventing urolithiasis. Moreover, STS was assumed to play a vital role in on ischemia reperfusion injury (IR). The effectiveness of STS as a cardioprotective agent was attributed to the reduction of apoptosis by binding to the active site of caspase-3 in silico, which was substantiated by the reduced expression of caspase-3 and poly ADP ribose polymerase levels.