These have a broad spectrum of activity and include the following drugs:
Cefotaxine (Biotax, Clazforn, Omnatax), Ceftazidime (Fotum), Ceftizoxime (Cefizox), Cefoperazone (Magnamycin), Ceftriaxone (Cefaxone, Monocef), Cefixime (Cefspan, Topcef), Cefdinir (Adcef), Cefpodoxime (Cepodem) Ceftibuten (Procadax).
Due to their ability to penetrate the central nervous sxstem, third-generation cephalosporins – except cefoperazone and cefixime – can be used to treat meningitis, including meningitis caused by pneumococci, meningococci, H influenzae, and susceptible gram-negative rods (bacillary infections of alimentary system). Cefoperazone and ceftazidine are effective in pseudomonas infections of various body organs. In these infections an aminoglycoslde such as gentamicin is also given. Other potential indications include sepsis of unknown causes in the immunocompetent patient and susceptible infections in which cephalosporins are the least toxic drugs available. In neutropenic, febrile immunocompromised patients, third-generation cephalosporins can be effective if used in combination with an aminoglycoslde. They are commonly used in hospital settings in patients with serious systemic infections. Ceficime, cefdinir, cefpodoxime and ceftibuten are effective orally also.
Cefepime (Kefage) can be used in resistant infections due to gram negative rods and staphylococci causing septicemia. Cefpirome (Cepodem, Cefoprox) has same utility as cefepime. These are very expensive.
Adverse Effects of Cephalosporins: Allergy: Cephalosporins are sensitizing and may variety of hypersensitivity reactions, including anaphylaxis, fever, skin rashes, nephritis, granulocytopenia, and hemolytic anaemia. The chemical nucleus of cephalosporins is sufficiently different from that of penicillins, enabling some individuals with a history of penicillin allergy to tolerate cephalosporins. However, patients with a history of anaphylaxis to penicillins should never receive cephalosporins.
Toxicity: Local irri!ation can produse severe pain after intramuscular injection and thrombophlebitis after intravenous injection. Renal toxicity, including interstitial nephritis (kidney tissue swelling) and even tubular necrosis, has been demonstrated and has caused the abandonment of cephaloridine.
Cephalosporins that contain a methylthiotetrazole group (for example, ceftriaxone, cefoperazone) frequently cause hypoprothrombinemia and bleeding disorders. Adminstration of vitamin K, 10 mg twice weekly, can prevent this. White cells count and platelet count are reduced in rare cases.
Drugs with the ‘methylthiotetrazole ring can also cause severe reaction with alcohol (intolerance), consequently, alcohol and alcohol-containing medications must be avoided.
Many second and particularly third generation cephalosporins are ineffective against grampositive organisms, especially stayphylococci and enterococci. During treatment with such drugs, these resistant organisms, as well as fungi, often proliferate and may induce super infection.
Linezolid (Lizolid, Linox)
It is effective in resistant pneumococci, staphylococci and enteric organisms induced infections. It may cause suppression of bone marrow and interacts with decongestant drugs whose dose should be reduced.
Ciprofloxacin (Cipad, Ciplox, Cipride), Norfloxacin (Anquin, Biofloxin, Norflox), Ofloxacin (Travid, Zanocid), Pefloxacin (Peflox, Piflasyn), Lomefloxacin (Lomef), Sparfloxacin (Torospar), Levofloxacin (Loxof), and Gatifloxacin (Gatri)
In 1990 fluoroquinolones were introduced to tackle ever increasing menace of resistance gram-negative rods. Since then many more drugs have been developed which have effects against both gram positive and negative bacteria, anaerobes and tuberculosis organisms. These drugs affect the DNA of bacteria. Unfortunately due to overuse, resistance is becoming the problem again.
Ciprofloxacin is presently a drug of choice for typhoid fever, (chloramphenicol is no longer used) gonorrhoea, abdominal (bowel) infections and diarrhoea, soft tissue and bone infections. It can be used 500 mg twice a day orally or intravenously in serious cases.
Adverse Effects: Some of the adverse effects of ciprofloxacin are loss of appetite, nausea and bowel upset, dizziness, restlessness, loss of sleep, poor concentration and tremulousness (avoid driving). Drug allergy may cause skin eruptions. A potentially serious problem is that it may cause cartilage damage as based on animal studies so should be used sparingly in children (although it is best to avoid it). Theophylline, caffeine, warfarm show toxicity when taken with ciprofloxacin and require staggering or reduction in dose. Pain relievers may cause more CNS adverse effects of ciprofloxacin. Antacids, milk and iron salts reduce absorption of ciprofloxacin, therefore, do not take with milk or after meals.
Norfloxacin is less potent to ciprojloxacin but is effective in the treatment of urinary tract infection and diarrhoea. Its usual dose is 400 mg twice a day in adult and it is not recommended for children.
Pefloxacin is a good drug for meningeal infections and typhoid fever. A single dose of 400 cures gonorrhoea.
Ofloxacin is effective in urethritis, cervicitis and atypical pneumonia. It is useful in tuberculosis also. Food does not reduce its absorption.
Sparfloxacin has greater activity to treat pneumonia, sinus infection, and ear infections, It is longer acting so it given in a dose of 200-400 mg once a day. It may cause disturbed heart beats particularly when other drugs are given along with it (drugs for depression and cisapride).
Gatefloxacin is like sparfloxacin in action and is increasingly used for the treatment of pneumonia, gonorrhoea, and urinary passage infections. Usual dose is 400 mg once a day. It has the same drawbacks as sparfloxacin.
Levofloxacin is completely absorbed orally and is less likely to interact with drugs (unlike ciprojloxacin and others). High cure rates are achieved in pneumonia, sinusitis, acute kidney infections and soft tissue infections. It is used in a dose of 500 mg once a day.