Saquinavir (brand names Invirase and Fortovase) is an antiretroviral drug used together with other medications to treat or prevent HIV/AIDS. Saquinavir is an inhibitor of HIV protease. HIV protease is an enzyme required for the proteolytic cleavage of viral polyprotein precursors into individual functional proteins found in infectious HIV. Saquinavir is a peptide-like substrate analog that binds to the protease active site and inhibits the activity of the enzyme. Saquinavir inhibition prevents cleavage of the viral polyproteins resulting in the formation of immature noninfectious virus particles. The most frequent adverse events with saquinavir in either formulation are mild gastrointestinal symptoms, including diarrhea, nausea, loose stools & abdominal discomfort. Invirase is better tolerated than Fortovase.

Levalmodipine (S-amlodipine) is an active enantiomer of amlodipine, a calcium antagonist that inhibits the transmembrane influx of calcium ions into vascular smooth muscle and cardiac muscle. Experimental data suggest that S-amlodipine binds to both dihydropyridine and nondihydropyridine binding sites. The contractile processes of cardiac muscle and vascular smooth muscle are dependent upon the movement of extracellular calcium ions into these cells through specific ion channels. S-Amlodipine inhibits calcium ion influx across cell membranes selectively, with a greater effect on vascular smooth muscle cells than on cardiac muscle cells. Enantiomerically pure S-amlodipine is marketed in some countries worldwide, while racemate, containing active S-enantiomer an inactive R-enantiomer is marketed in the USA and indicated for the treatment of hypertension and coronary artery disease.

Halofantrine is a blood schizonticidal antimalarial agent with no apparent action on the sporozoite, gametocyte or hepatic stages of the infection. It is used only to treat but not to prevent malaria. Has been marketed by GlaxoSmithKline as HALFAN (halofantrine hydrochloride) in 250 mg tablets indicated for the treatment of adults who can tolerate oral medication and who have mild to moderate malaria (equal to or less than 100,000 parasites/mm3) caused by Plasmodium falciparum or Plasmodium vivax. Among side effects is cardiac arrhythmia. It belongs to the phenanthrene class of compounds that includes quinine and lumefantrine. It was reported that halofantrine binds to hematin in vitro (crystal structure of the complex) and to to plasmpesin, a haemoglobin degrading enzyme unique to the malarial parasites.

Beclometasone dipropionate or beclomethasone dipropionate is sold under the brand name Qvar among others. Beclomethasone dipropionate is a corticosteroid demonstrating potent anti-inflammatory activity. The precise mechanism of corticosteroid action on asthma is not known. Corticosteroids have been shown to have multiple anti-inflammatory effects, inhibiting both inflammatory cells (e.g., mast cells, eosinophils, basophils, lymphocytes, macrophages, and neutrophils) and release of inflammatory mediators (e.g., histamine, eicosanoids, leukotrienes, and cytokines). These anti-inflammatory actions of corticosteroids may contribute to their efficacy in asthma. Beclomethasone dipropionate is a prodrug that is rapidly activated by hydrolysis to the active monoester, 17 monopropionate (17-BMP). Beclomethasone 17 monopropionate has been shown in vitro to exhibit a binding affinity for the human glucocorticoid receptor, which is approximately 13 times that of dexamethasone, 6 times that of triamcinolone acetonide, 1.5 times that of budesonide and 25 times that of beclomethasone dipropionate. The clinical significance of these findings is unknown. Studies in patients with asthma have shown a favorable ratio between topical anti-inflammatory activity and systemic corticosteroid effects with recommended doses of QVAR. Beclometasone dipropionate was first patented in 1962 and used medically in 1972. Common side effects with the inhaled form include respiratory infections, headaches, and throat inflammation. Serious side effects include an increased risk of infection, cataracts, Cushing’s syndrome, and severe allergic reactions. Long term use of the pill form may cause adrenal insufficiency. The pills may also cause mood or personality changes. The inhaled form is generally regarded as safe in pregnancy. Beclometasone is mainly a glucocorticoid.

Niclosamide is an antihelminth used against tapeworm infections. It may act by the uncoupling of the electron transport chain to ATP synthase. The disturbance of this crucial metabolic pathway prevents creation of adenosine tri-phosphate (ATP), an essential molecule that supplies energy for metabolism. Niclosamide works by killing tapeworms on contact. Adult worms (but not ova) are rapidly killed, presumably due to uncoupling of oxidative phosphorylation or stimulation of ATPase activity. The killed worms are then passed in the stool or sometimes destroyed in the intestine. Niclosamide may work as a molluscicide by binding to and damaging DNA. Niclosamide is used for the treatment of tapeworm and intestinal fluke infections: Taenia saginata (Beef Tapeworm), Taenia solium (Pork Tapeworm), Diphyllobothrium latum (Fish Tapeworm), Fasciolopsis buski (large intestinal fluke). Niclosamide is also used as a molluscicide in the control of schistosomiasis. Niclosamide was marketed under the trade name Niclocide, now discontinued.

Triclosan was used as a hospital scrub in the 1970s. Since then, it has expanded commercially and is now prevalent in soaps (0.10-1.00%), shampoos, deodorants, toothpastes, mouth washes, cleaning supplies and pesticides. It is part of consumer products, including kitchen utensils, toys, bedding, socks and trash bags. In healthcare, triclosan is used in surgical scrubs and hand washes. Use in surgical units is effective with a minimum contact time of approximately two minutes. More recently, showering with 2% triclosan has become a recommended regimen in surgical units for the decolonization of patients whose skin carries methicillin-resistant Staphylococcus aureus (MRSA). Triclosan is also used in the coatings for some surgical sutures. Triclosan has been employed as a selective agent in molecular cloning. At high concentrations, triclosan acts as a biocide with multiple cytoplasmic and membrane targets. However, at the lower concentrations seen in commercial products, triclosan appears bacteriostatic, and it targets bacteria primarily by inhibiting fatty acid synthesis. Triclosan binds to bacterial enoyl-acyl carrier protein reductase (ENR) enzyme, which is encoded by the gene FabI. This binding increases the enzyme's affinity for nicotinamide adenine dinucleotide (NAD+). This results in the formation of a stable, ternary complex of ENR-NAD+-triclosan, which is unable to participate in fatty acid synthesis. Fatty acids are necessary for building and reproducing cell membranes. Humans do not have an ENR enzyme and thus are not affected.

Amodiaquine is a medication used to treat malaria, including Plasmodium falciparum malaria when uncomplicated. The mechanism of plasmodicidal action of amodiaquine is not completely certain. Like other quinoline derivatives, it is thought to inhibit heme polymerase activity. This results in accumulation of free heme, which is toxic to the parasites. The drug binds the free heme preventing the parasite from converting it to a form less toxic. This drug-heme complex is toxic and disrupts membrane function. The side effects of amodiaquine are generally minor to moderate and are similar to those of chloroquine. Rarely liver problems or low blood cell levels may occur. When taken in excess headaches, trouble seeing, seizures, and cardiac arrest may occur. After oral administration amodiaquine hydrochloride is rapidly absorbed,and undergoes rapid and extensive metabolism to desethylamodiaquine which concentrates in red blood cells. It is likely that desethylamodiaquine, not amodiaquine, is responsible for most of the observed antimalarial activity, and that the toxic effects of amodiaquine after oral administration may in part be due to desethylamodiaquine.

Quinacrine was initially developed as an anti-malarial drug marketed under the name Atabrine. Also it was approved for the teratment of ascites, however it was wothdrawn for both indication in 1995 and 2003, respectively. The drug is also used for the treatment of giardiasis, lupus, rheumatoid arthritis, refractory pulmonary effusion and pneumothorax, induce female sterilization etc. Proposed mechanisms of action include DNA intercalation interference with RNA transcription and translation, inhibition of succinate oxidation interference with electron transport, inhibition of cholinesterase, and inhibitor of phospholipase.

Aconitine is an alkaloid found in the Aconitum species. Aconitine is a highly toxic cardiotoxin and neurotoxin. In China and other countries, the herbal extract containing aconitine was used for the treatment of pain in musculoskeletal disorders, however the safety margin between therapeutic analgesic effect of aconitine and its known cardiotoxic effect is so narrow that the treatment may cause poisoning and death. The mechanism of aconitine action is explained by its ability to activate voltage-dependent sodium-ion channels.