Pipacycline is a semi-synthetic tetracycline formed by a Mannich condensation of formaldehyde and 4-hydroxyethyl piperazine with tetracycline. The introduction of the piperazine improves bioavailability, but Mannich bases are pro-drugs, converting back to the parent compound. Pipacycline is used commercially as a salt in combination with penicillin V for parenteral use (penimepicycline). Penimepicycline exerts a bactericidal action on the streptococci, and a bacteriostatic action on various gram-positive and gram-negative bacilli, as well as on the penicillin-resistant staphylococci.

Lymecycline is a tetracycline broad-spectrum antibiotic marketed by the pharmaceutical company Galderma. It is approximately 5,000 times more soluble than tetracycline base and is unique amongst tetracyclines in that it is absorbed by an active transport process across the intestinal wall, making use of the same fast and efficient mechanism by which carbohydrates are absorbed. Lymecycline's side effects can include rash, headache, diarrhoea, ulcerative colitis, nausea, vomiting, dermatitis, dysphasia, inflammation of the liver, hypersensitive reactions, and visual disturbances. When taken for a long period of time, it can cause reflux oesophagitis.

Rolitetracycline nitrate is an antibiotic formed by N-aminomethylation of the carboxamide group of tetracycline. Rolitetracycline passively diffuses through porin channels in the bacterial membrane and reversibly binds to the 30S ribosomal subunit, preventing binding of tRNA to the mRNA-ribosome complex, and thus interfering with protein synthesis. It is formulated for intravenous or intramuscular injections and is used in cases requiring high concentrations or when oral administration is impractical. In combinations with chloramphenicol and colistin, it is used as the eye drops for the treatment of external eye infections such as catarrhal conjunctivitis, purulent, trachoma, blepharitis, blepharoconjunctivitis, bacterial keratitis, septic corneal ulcers.

Neomycin is an aminoglycoside antibiotic found in many topical medications such as creams, ointments, and eye drops. In vitro tests have demonstrated that neomycin is bactericidal and acts by inhibiting the synthesis of protein in susceptible bacterial cells. It is effective primarily against gram-negative bacilli but does have some activity against gram-positive organisms. Neomycin is active in vitro against Escherichia coli and the Klebsiella-Entero. Topical uses include treatment for superficial eye infections caused by susceptible bacteria (used in combination with other anti-infective), treatment of otitis externa caused by susceptible bacteria, treatment or prevention of bacterial infections in skin lesions, and use as a continuous short-term irrigant or rinse to prevent bacteriuria and gram negative rod bacteremia in bacteriuria patients with indwelling catheters. May be used orally to treat hepatic encephalopathy, as a perioperative prophylactic agent, and as an adjunct to fluid and electrolyte replacement in the treatment of diarrhea caused to enter pathogenic E. coli (EPEC). Neomycin sulfate has been shown to be effective adjunctive therapy in hepatic coma by reduction of the ammonia forming bacteria in the intestinal tract. The subsequent reduction in blood ammonia has resulted in neurologic improvement. To reduce the development of drug-resistant bacteria and maintain the effectiveness of Neomycin Sulfate Oral Solution and other antibacterial drugs, susceptible bacteria should use Neomycin Sulfate Oral Solution only to treat or prevent infections that are proven or strongly suspected to be caused. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy. Neomycin binds to four nucleotides of 16S rRNA and a single amino acid of protein S12. This interferes with decoding site near nucleotide 1400 in 16S rRNA of 30S subunit. This region interacts with the wobble base in the anticodon of tRNA. This leads to interference with the initiation complex, misreading of mRNA so incorrect amino acids are inserted into the polypeptide leading to nonfunctional or toxic peptides and the breakup of polysomes into nonfunctional monosomes