Clindamycin hydrochloride is the hydrated hydrochloride salt of clindamycin. Clindamycin is a semisynthetic antibiotic produced by a 7(S)-chloro-substitution of the 7(R)-hydroxyl group of the parent compound lincomycin. Clindamycin inhibits bacterial protein synthesis by binding to the 50S subunit of the ribosome. It has activity against Gram-positive aerobes and anaerobes as well as some Gram-negative anaerobes.

Primaquine is a oral medication used to treat and prevent malaria and to treat Pneumocystis pneumonia. Specifically it is used for malaria due to Plasmodium vivax and Plasmodium ovale along with other medications and for prevention if other options cannot be used. Primaquine is an alternative treatment for Pneumocystis pneumonia together with clindamycin. Primaquine is lethal to P. vivax and P. ovale in the liver stage, and also to P. vivax in the blood stage through its ability to do oxidative damage to the cell. However, the exact mechanism of action is not fully understood. Primaquine is well-absorbed in the gut and extensively distributed in the body without accumulating in red blood cells. Administration of primaquine with food or grapefruit juice increases its oral bioavailibity. In blood, about 20% of circulating primaquine is protein-bound, with preferential binding to the acute phase protein orosomucoid. With a half-life on the order of 6 hours, it is quickly metabolized by liver enzymes to carboxyprimaquine, which does not have anti-malarial activity. Common side effects of primaquine administration include nausea, vomiting, and stomach cramps. Primaquine phosphate is recommended only for the radical cure of vivax malaria, the prevention of relapse in vivax malaria, or following the termination of chloroquine phosphate suppressive therapy in an area where vivax malaria is endemic. Patients suffering from an attack of vivax malaria or having parasitized red blood cells should receive a course of chloroquine phosphate, which quickly destroys the erythrocytic parasites and terminates the paroxysm. Primaquine phosphate should be administered concurrently in order to eradicate the exoerythrocytic parasites in a dosage of 1 tablet (equivalent to 15 mg base) daily for 14 days.

Discovered as natural products from actinomycetes soil bacteria, the tetracyclines were first reported in the scientific literature in 1948. They were noted for their broad spectrum antibacterial activity and were commercialized with clinical success beginning in the late 1940s to the early 1950s. By catalytic hydrogenation of Aureomycin, using palladium metal and hydrogen, the C7 deschloro derivative was synthesized, producing a compound of higher potency, a better solubility profile, and favorable pharmacological activity; it was subsequently named tetracycline. Tetracyclines are primarily bacteriostatic and exert their antimicrobial effect by the inhibition of protein synthesis by binding to the 30S ribosomal subunit. Tetracycline is active against a broad range of gram-negative and gram-positive organisms. Tetracycline is indicated in the treatment of infections caused by susceptible strains. To reduce the development of drug-resistant bacteria and maintain the effectiveness of tetracycline hydrochloride and other antibacterial drugs, tetracycline hydrochloride should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria.

Grepafloxacin is a monofluorinated quinolone with a cyclopropyl group at position 1, a 3-methyl-1piperazinyl group at position 7 and a methyl substitution at the 5 position, that was synthesized by Otsuka in Japan. It exhibited in vitro activity against a wide variety of both Gram-positive and Gram-negative bacteria including anaerobic species. The compound was reported to have a broad spectrum of activity, particularly against pathogens responsible for community-acquired respiratory infections including those caused by beta-lactam and macrolide-resistant strains of Streptococcus pneumoniae and Haemophilus influenzae. Japanese researchers also reported that unlike other quinolones, grepafloxacin reached high levels in the bile and might also be useful in the treatment of biliary tract infection. Grepafloxacin was administered once daily and did not require dosage adjustment for renal insufficiency, but grepafloxacin tablets were contraindicated in patients with hepatic failure. Otsuka Pharmaceutical signed a licensing agreement for grepafloxacin with GlaxoSmithKline. According to this agreement, GlaxoSmithKline had marketing rights to grepafloxacin in Europe, USA, and certain other markets. Otsuka retained rights for Japan and some Asian countries

Alatrofloxacin is a fluoroquinolone antibiotic developed as a mesylate salt and was sold under brand name Trovan, but was withdrawn from the U.S. market in 2001. Trovan was indicated for the treatment of patients initiating therapy in in-patient health care facilities (i.e., hospitals and long term nursing care facilities) with serious, life- or limb-threatening infections caused by susceptible strains of the designated microorganisms in the conditions listed below. Nosocomial pneumonia caused by Escherichia coli, Pseudomonas aeruginosa, Haemophilus influenzae, or Staphylococcus aureus. Community acquired pneumonia caused by Streptococcus pneumoniae, Haemophilus influenzae, Klebsiella pneumoniae, Staphylococcus aureus. Complicated intra-abdominal infections, including post-surgical infections caused by Escherichia coli. Gynecologic and pelvic infections including endomyometritis, parametritis, septic abortion and post-partum infections caused by Escherichia coli, Bacteroides fragilis, viridans group streptococci, Enterococcus faecalis. Complicated skin and skin structure infections, including diabetic foot infections, caused by Staphylococcus aureus, Streptococcus agalactiae, Pseudomonas aeruginosa, Enterococcus faecalis, Escherichia coli, or Proteus mirabilis. After intravenous administration, alatrofloxacin is rapidly converted to trovafloxacin, which is responsible for therapeutic effect. Plasma concentrations of alatrofloxacin are below quantifiable levels within 5 to 10 minutes of completion of a 1 hour infusion.