Classification

Antibacterial mechanism

Antibacterial spectrum

internal processes

① Structure-activity relationship: Antibacterial activity ↑ Antibacterial spectrum ↑, central nervous system toxicity; lipid solubility ↑, photosensitivity; hepatotoxicity and cardiotoxicity ② Antibacterial spectrum: broad-spectrum and powerful bactericidal (levofloxacin has the strongest effect on Gram-positive bacteria) ③ Resistance mechanism: The affinity of the target mutation decreases, the permeability of the cytoplasmic membrane decreases, and active efflux↑ ④ Adverse reactions: Floxacin will damage cartilage. Do not taste it if you are under 18. It may damage the stomach due to mental poisoning. Be careful not to see the light.

⑦Clinical application: Urogenital tract infections (ciprofloxacin and β-lactams are both the first-choice drugs); respiratory system infections (the combination of levoflumox and vancomycin is the first-choice drug for the treatment of highly penicillin-resistant pneumonia) Streptococcal infections. It can replace macrolides for mycoplasma, chlamydia, and legionella infections); intestinal infections and typhoid fever (the first choice for the treatment of acute and chronic bacillary dysentery and toxic bacillary dysentery caused by Shigella. For infections caused by Salmonella For typhoid or paratyphoid, fluoroquinolones or ceftriaxone are the first choice (for Pseudomonas aeruginosa, ciprofloxacin is the first choice); radical treatment of nasopharyngeal carriers of meningococcal meningitis; severe infections in children; bone, joint and soft tissue infections; abdominal biliary tract infections and Pelvic infection: It needs to be combined with anti-anaerobic drugs such as metronidazole. Moxifloxacin can be used as a single drug to treat mild cases; some varieties can be used in combination with other drugs as a second-line drug for the treatment of drug-resistant Mycobacterium tuberculosis and other mycobacterial infections.

⑧Contraindications and drug interactions: It is forbidden for pregnant women with allergies and breastfeeding infants and young children; it should be used with caution in patients with mental illness and epilepsy, and it should not be used routinely in children; Metal ions of antacids reduce their bioavailability; enoxacin, ciprofloxacin, etc. inhibit the metabolism of theophylline in the liver (ofloxacin does not have this effect); nonsteroidal anti-inflammatory drugs increase their central toxic reactions; Appropriate dose reduction for patients with reduced renal function: ofloxacin, enoxacin

Norfluro (Coward), Fluro (Florence); Cipro (Potato Pancake); Oxofuride; Spamoxil (Little Japan is fighting); Gatigare There was a coward who ate a potato pancake in Florence, then looked up at the sky and held his chin, remembering that when he was fighting with the Japanese, he blew them up with two grenades.

① Antibacterial spectrum: G G- (meningococci) are effective; the most sensitive (group A pneumonia, meningococci, plague Yernoka); sulfamethoxazole SMZ is effective against typhoid bacilli, and sulfadiazine silver SD-Ag is effective against Pseudomonas aeruginosa Bacilli are effective ② Antibacterial mechanism: Affects folic acid metabolism; sulfonamides compete with PABA for dihydrofolate reductase, and trimethoprim inhibits dihydrofolate reductase → sulfonamide + trimethoprim (enhances the antibacterial effect, expands the antibacterial spectrum, and delays drug resistance) ③Resistance mechanism: Intrinsic resistance (membrane ↓, direct use of existing folic acid in the environment); acquired resistance (chromosome mutation to synthesize excess PABA, Escherichia coli produces low-affinity dihydrofolate pteridase; plasmid-mediated acquisition Plasmid of drug-resistant dihydrofolate pteridase); congeneric cross-resistance ④In vivo process: Complete absorption and wide distribution; plasma protein binding rate SD25% SMZ86%; SD can pass through the BBB and placenta; hepatic acetylation metabolism and renal excretion; high solubility in alkaline urine and easy crystallization in acidic urine ( Alkalinize urine to promote excretion) The solubility of the acetyl compound is lower than that of the parent drug. ⑤Drug interactions: High plasma protein binding rate → Pay attention to reducing the dosage when combined with oral hypoglycemic drugs coumarins, especially the anti-tumor drug methotrexate. So does aspirin.

⑤Adverse reactions: Urinary system and kidney damage → alkalize urine, drink more water to promote excretion, and check urine regularly; allergy - exfoliative dermatitis with rash - → contraindicated if there is a history of cross-allergy; blood system WBC aplastic anemia, kernicterus G-6PD in children Deficiency can cause acute hemolytic anemia; CNS reaction - dizziness, headache, inability to concentrate and insomnia; liver damage → hepatic insufficiency is contraindicated; neonates, premature infants, pregnant and breastfeeding women are contraindicated

⑥Clinical application

Trimethoprim (TMP)

Compound sulfamethoxazole: SMZ+TMP (5:1); Dipyrimidine tablets=SD+TMP

Furans

Metronidazole