Dihydro-alpha-ergocryptine is an ergot alkaloid that has an agonist activity on D2 dopaminergic receptors and a partial agonist activity on D1 receptors. It also demonstrated antagonistic activity towards alpha-adrenergic receptors. The drug was approved by FDA in combination with other alkaloids (dihydroergocornine, dihydroergocristine and dihydro-beta-ergocryptine mesylate salts) under the name Hydergine for the treatment of dimentia and cerebrovascular insufficiency.

Lindane is an isomer of hexachlorocyclohexane that has been used both as an agricultural insecticide and as a pharmaceutical. As a shampoo, lindane is used for treamtment lice infestation. Lindane lotion is used for treatment of scabies. Due to toxicities, associated with lindane, it is used only in patients who cannot tolerate or have failed first-line treatment with safer medication. Lindane exerts its parasiticidal action by being directly absorbed into the parasites and their ova, where it interferes with GABA neurotransmitter function by interacting with the GABAA channel complex at the picrotoxin binding site.

Diethylcarbamazine is used in humans, dogs and cats for the treatment of parasitic infections, including pulmonary eosinophilia, loiasis, and lymphatic filariasis. The exact mechanism of its action is unknown, however some studies showed the involvment of inducible nitric-oxide synthase and the cyclooxygenase pathway. Although there is no information on whether the drug is marketed in the USA and Europe, it is currently used in India.

Chloramphenicol is a broad-spectrum antibiotic that was first isolated from Streptomyces venezuelae in 1947. The drug was subsequently chemically synthesized. It has both a bacteriostatic and bactericidal effect; in the usual therapeutic concentrations it is bacteriostatic. Chloramphenicol is used for the treatment of serious gram-negative, gram-positive, and anaerobic infections. It is especially useful in the treatment of meningitis, typhoid fever, and cystic fibrosis. It should be reserved for infections for which other drugs are ineffective or contraindicated. Chloramphenicol, a small inhibitor of bacterial protein synthesis, is active against a variety of bacteria and readily enters the CSF. It has been used extensively in the last decades for the treatment of bacterial meningitis. In industrialized countries, chloramphenicol is restricted mostly to topical uses because of the risk of induction of aplastic anemia. However, it remains a valuable reserve antibiotic for patients with allergy to β-lactam antibiotics or with CNS infections caused by multiresistant pathogens.

Khellin is a crystalline extract of a crude drug, which has long been used in Egypt for the treatment of ureteral colic. It is used in the management of bronchial asthma and angina pectoris. Interest in khellin as an adjunct to ultraviolet (UV) light therapy in the treatment of vitiligo is based on the structural similarity between khellin and the psoralens. Success has been reported using oral and topical khellin in clinical studies but it is not likely that khellin will be approved for the treatment of vitiligo. Unwanted side effects of khellin include dizziness, reversible cholestatic jaundice, pseudoallergic reaction, and elevated levels of liver enzymes (transaminases and gamma-glutamyltransferase).

METHYLHEXANEAMINE, an amphetamine derivative, is also known as 1,3-dimethylamylamine (DMAA). It was introduced in 1948 as a nasal inhaler for allergic or infectious rhinitis. By the 1970s, it had been withdrawn from the market. DMAA is currently used as an ingredient in many sports performance and weight loss products. According to FDA, it is not a dietary ingredient, and DMAA-containing products marketed as dietary supplements are illegal and their marketing violates the law.

Sulfisoxazole is a sulfonamide antibacterial antibiotic. The sulfonamides are synthetic bacteriostatic antibiotics with a wide spectrum against most gram-positive and many gram-negative organisms. However, many strains of an individual species may be resistant. Sulfisoxazole acetyl in combination with erythromycin ethylsuccinate is used for treatment of ACUTE OTITIS MEDIA in children that is caused by susceptible strains of Haemophilus influenzae. Sulfisoxazole acetyl is a prodrug of sulfisoxazole. Acetyl group is added to make the drug poorly water soluble, and is hydrolyzed in vivo to the active drug. Sulfisoxazole and its acetylated metabolites are excreted primarily by the kidneys through glomerular filtration. Sulfisoxazole is a competitive inhibitor of the enzyme dihydropteroate synthetase. It inhibits bacterial synthesis of dihydrofolic acid by preventing the condensation of the pteridine with para-aminobenzoic acid (PABA), a substrate of the enzyme dihydropteroate synthetase. The inhibited reaction is necessary in these organisms for the synthesis of folic acid

Sulfamethazine is a sulfonamide used to treat a variety of bacterial diseases in animals. It inhibits bacterial synthesis of dihydrofolic acid by competing with para-aminobenzoic acid (PABA) for binding to dihydropteroate synthetase (dihydrofolate synthetase).

Sulfabenzamide is an antibacterial/antimicrobial. Often used in conjunction with sulfathiazole and sulfacetamide (trade name - Sultrin) as a topical, intravaginal antibacterial preparation against Haemophilus (Gardnerella) vaginalis bacteria. The mode of action of SULTRIN is not completely known. Indirect effects, such as lowering the vaginal pH, may be equally important mechanisms.

Tubocurarine, a naturally occurring alkaloid, is used to treat smoking withdrawl syndrom. Tubocurarine, the chief alkaloid in tobacco products, binds stereo-selectively to nicotinic-cholinergic receptors at the autonomic ganglia, in the adrenal medulla, at neuromuscular junctions, and in the brain. Two types of central nervous system effects are believed to be the basis of Tubocurarine's positively reinforcing properties. A stimulating effect is exerted mainly in the cortex via the locus ceruleus and a reward effect is exerted in the limbic system. At low doses the stimulant effects predominate while at high doses the reward effects predominate. Intermittent intravenous administration of Tubocurarine activates neurohormonal pathways, releasing acetylcholine, norepinephrine, dopamine, serotonin, vasopressin, beta-endorphin, growth hormone, and ACTH. Tubocurarine competes with acetylcholine for post-synaptic nicotinic NM receptors and blocks them.