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Antibiotic Medications |   |
Aminoglycosides, a group of agents derived from different species of Streptomyces, act by preventing and distorting bacterial protein synthesis. Gentamicin, amikacin kanamycin, tobramycin, and streptomycin are used for treating gram-negative bacillary pneumonias. Aminoglycosides are inhaled to control Pseudomonas infection in cystic fibrosis. Their most significant side-effect is damage to renal tubules.
Tetracyclines are derived from Streptomyces species, and can be bacteriostataic or bactericidal, depending on dosage. They interfere with protein synthesis, and are effective against streptococcus pneumoniae, hemophilus influenzae, and mycoplasma pneumoniae. Tetracyclines are used as a prophylactic and for acute exacerbations of chronic bronchitis. Milk and milk products interfere with their absorption from the gastrointestinal tract. Side-effects from using tetracyclines include gastrointestinal irritation, vomiting and diarrhea, bone marrow depression and skin rashes. Since they are temporarily incorporated in the liver and kidneys, they should be used with caution, if at all, for patients with liver or renal disease.
Fluoroquinolones are synthetic quinolone derivatives with broad spectrum activity against bacterial activity. Examples include ciprofloxacin, norfloxacin, ofloxacin, enoxacin, and lomefloxacin. When orally administered, these drugs provide high lung bioavailability.
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Sulfonamides are not classed as antibiotics, but were the first effective group of chemotherapeutic agents used to treat systemic bacterial infections. With the availability of many natural and semisynthetic antibacterial agents, their use has declined. They are still used to treat intestinal and urinary tract infections, but are generally longer used for treating gonococcal, staphylococcal, or streptococcal infections. |
Trimethoprim-Sulfamethoxazole (TMP-SMX) is not an antibiotic, but a chemical agent produced in the laboratory. It is an antibacterial agent commonly used to treat respiratory infections, and is the drug of choice for treatment of P. carinii in AIDS patients. Side effects include rash, fever and leukopenia.
Polymyxins, B and E, are polypeptide antibiotics. Polymyxin B is effective against gram-negative organisms, particularly pseudomonas. It disturbs osmotic properties of the cell membrane in its action. It can be aerosolized for both pseudomonas and gram-negative bacteria colonizing the airway. Polymyxin B is usually given intramuscularly. Renal damage is the major problem with its use. When aerosolized, severe bronchospasm may result. It also can cause a neuromuscular blockade leading to respiratory paralysis. Polymyxin E is known as colistin and is similar to polymyxin B.
Erythromycins are macrolide antibiotics that are used for respiratory, genital, gastrointesstinal tract, and skin/soft tissue infections. These agents bind to a site on the 50S ribosomal subunit of organisms, thereby acting to inhibit protein synthesis. They are drugs of choice in treating against gram-positive organisms including pneumococcus, mycoplasma pneumoniae, chlamydia psittici, beta hemolytic streptococcus and some hemophilus influenzae. Erythromycin also has been used for Legionnaires disease, and for patients who are allergic to penicillin.
Erythromycin, one of the safest antibiotics, is available by oral, IM, or IV administration. Possible side effects include nausea, vomiting, diarrhea, phlebitis and pain on injection. Erythromycin is primarily used for community-acquired pneumonia. Clarithromycin and azithromycin have been effective in treating disseminated Myobacterium avium-intracellulare in AIDS patients. Clindamycin is effective against some staphylococcus aureus, diplococcus, bacteroides and other gram positive organisms. Specific pulmonary indications for its use are aspiration pneumonias, empyema. and lung abscess. Side effects include diarrhea and skin rashes.