Dextromycetin - General Information
An antibiotic first isolated from cultures of Streptomyces venequelae in 1947 but now produced synthetically. It has a relatively simple structure and was the first broad-spectrum antibiotic to be discovered. It acts by interfering with bacterial protein synthesis and is mainly bacteriostatic. (From Martindale, The Extra Pharmacopoeia, 29th ed, p106)
Pharmacology of Dextromycetin
Dextromycetin is a broad-spectrum antibiotic that was derived from the bacterium Streptomyces venezuelae and is now produced synthetically. Dextromycetin is effective against a wide variety of microorganisms, but due to serious side-effects (e.g., damage to the bone marrow, including aplastic anemia) in humans, it is usually reserved for the treatment of serious and life-threatening infections (e.g., typhoid fever). Dextromycetin is bacteriostatic but may be bactericidal in high concentrations or when used against highly susceptible organisms. Dextromycetin stops bacterial growth by binding to the bacterial ribosome (blocking peptidyl transferase) and inhibiting protein synthesis.
Additional information about Dextromycetin
Dextromycetin Indication: Used in treatment of cholera, as it destroys the vibrios and decreases the diarrhea. It is effective against tetracycline-resistant vibrios. It is also used in eye drops or ointment to treat bacterial conjunctivitis.
Mechanism Of Action: Dextromycetin is lipid-soluble, allowing it to diffuse through the bacterial cell membrane. It then reversibly binds to the 50S subunit of bacterial ribosomes where transfer of amino acids to growing peptide chains is prevented (perhaps by suppression of peptidyl transferase activity), thus inhibiting peptide bond formation and subsequent protein synthesis.
Drug Interactions: Acetohexamide The agent increases the effect of sulfonylurea
Anisindione Increases the anticoagulant effect
Chlorpropamide The agent increases the effect of sulfonylurea
Cyclosporine Increases the effect of cyclosporine
Dicumarol Increases the anticoagulant effect
Ethotoin Increases phenytoin, modifies chloramphenicol
Fosphenytoin Increases phenytoin, modifies chloramphenicol
Gliclazide The agent increases the effect of sulfonylurea
Glipizide The agent increases the effect of sulfonylurea
Glisoxepide The agent increases the effect of sulfonylurea
Glibenclamide The agent increases the effect of sulfonylurea
Glycodiazine The agent increases the effect of sulfonylurea
Mephenytoin Increases phenytoin, modifies chloramphenicol
Acenocoumarol Increases the anticoagulant effect
Phenytoin Increases phenytoin, modifies chloramphenicol
Rifampin Rifampin decreases the effect of chloramphenicol
Tacrolimus Increases tacrolimus levels
Tolazamide The agent increases the effect of sulfonylurea
Tolbutamide The agent increases the effect of sulfonylurea
Warfarin Increases the anticoagulant effect
Food Interactions: Take on an empty stomach.
Generic Name: Chloramphenicol
Synonyms: CAF; CAM; CAP; Chloramphenicole; Chloramfenikol; Chloroamphenicol; Cloroamfenicolo; CPh; D-Chloramphenicol
Drug Category: Anti-Bacterial Agents; Protein Synthesis Inhibitors
Drug Type: Small Molecule; Approved
Absorption: Rapidly and completely absorbed from gastrointestinal tract following oral administration (bioavailability 80%). Well absorbed following intramuscular administration (bioavailability 70%). Intraocular and some systemic absorption also occurs after topical application to the eye.
Toxicity (Overdose): Oral, mouse: LD50 = 1500 mg/kg; Oral, rat: LD50 = 2500 mg/kg. Toxic reactions including fatalities have occurred in the premature and newborn; the signs and symptoms associated with these reactions have been referred to as the gray syndrome. Symptoms include (in order of appearance) abdominal distension with or without emesis, progressive pallid cyanosis, vasomotor collapse frequently accompanied by irregular respiration, and death within a few hours of onset of these symptoms.
Protein Binding: Plasma protein binding is 50-60% in adults and 32% is premature neonates.
Biotransformation: Hepatic, with 90% conjugated to inactive glucuronide.
Half Life: Half-life in adults with normal hepatic and renal function is 1.5 - 3.5 hours. In patients with impaired renal function half-life is 3 - 4 hours. In patients with severely impaired hepatic function half-life is 4.6 - 11.6 hours. Half-life in children 1 month to 16 years old is 3 - 6.5 hours, while half-life in infants 1 to 2 days old is 24 hours or longer and is highly variable, especially in low birth-weight infants.
Dosage Forms of Dextromycetin: Powder, for solution Intramuscular
Solution / drops Ophthalmic
Chemical IUPAC Name: 2,2-dichloro-N-[1,3-dihydroxy-1-(4-nitrophenyl)propan-2-yl]acetamide
Chemical Formula: C11H12Cl2N2O5
Chloramphenicol on Wikipedia: https://en.wikipedia.org/wiki/Chloramphenicol
Organisms Affected: Enteric bacteria and other eubacteria