Sulphanomides Flashcards
What type of antiinfectives are sulphanomides?
Antibacterics - chemotherapeutics
Characterize sulphanomides:
Complex synthetic organic chemical compounds.
Bacteriostatic activity.
Spectrum of action of sulphanomides:
- Gram positive and Gram negative bacteria: streptococcus, staphylococcus, haemophilius, bacteroides, brucella, corynebacterium, chlamydia and toxoplasma gondii
- wide using
- plasmid mediated resistance in G+ and G- bacteria: enterococcus, campylobacter, pseudomonas, mycoplasma, mycobacterium
Farmacokinetics of sulphanomides:
- bind to plasma albumin
- high doses application
- unbounded molecules can penetrate into tissues, organs, placenta, milk
- eliminated in urine, perspiration, tears, bile, milk
Minimum therapeutic concentration in blood for reaching bacteriostatic effect:
2-10 mg%
Mechanism of action of sulphanomides:
Structural analogs of PABA
- competitively inhibit dihydropteroate synthase –> reduced synthesis of dihydrofolic acid –> levels of tetrahydrofolate diminish –> suppression of protein synthesis –> impairment of metabolic processes –> inhibition of microbial growth and multiplication
BACTERIOSTATIC
Mechanism of action of potentiated sulfanomides:
diaminopyrimidine used in combination competively inhibits dihydrofolate reductase enzyme to prevent the formation of folinic acid, required for the synthesis of DNA
BACTERICIDAL
Trimethoprim and sulfanomides used separately have which effect?
And which effect does the combination have?
Bacteriostatic, but becomes bactericidal when used in combination
What is the standard use of sulfanomides?
- upper and lower respiratory tract infections
- urogenital system
- erysipelas, septicemia, pyemia
- secondary bacterial infections in viral diseases
- coccidosis
D: 1-4 x daily. 120-150 mg/kg p.o., 60-75 mg/kg s.c., i.m.
(potentiated are administered as 1/2 or 1/3)
Classify sulfanomides according to duration of action:
- Short-acting: above 50 ug/ml <12h (sulfadiazine)
- Intermediate-acting: above 50 ug/ml for 12-24 h (sulfamethoxazole)
- Long-acting: 50 ug/ml obtained after 24h after dosing (sulfadoxine, sulfamethopyrazine)
Name short-acting sulphanomides:
sulfathiazole, sulfacetamide
Name long-acting sulphanomides:
sulfamidine, sulfadiazine, sulfamerazine, sulfaqmetoxazole
Name long-acting sulphanomides:
sulfamethoxypyridazine, sulfadoxine, sulfadimethoxine
Divide sulphanomides according to solubility/or administration:
Highly soluble - urinary tract infections
Poorly soluble - intestinal infection:
- ulcerative colitis in dog
- caecal and intestinal coccidosis (sulfaquinoxaline and sulfaclozine)
Topical sulfanomides:
- ophtalmic infections
- burn wounds
Name adverse and undesired effects of sulphanomides:
Hepatitis, hypersensitivity, bone marrow depression
Nausea and vomiting, disorders in digestion and urinary tract
Crystalluria - impairment of kidney tubules (in low pH)
Cyanosis
Hemorrhagic syndrome (vit. K synthesis)
Reduction of vit. B synthesis (suppression of gut microflora)
Contraindications of sulphanomides:
Hypersensitivity, severe renal or hepatic impairment
Hepatic disease
Urolithiasis
Name enteric and local sulphanomides:
phthalylsulfatiazole (Streptonamid), sulfaclozinum (Klozanit)
How does quinolones and fluoroquinolones act?
Inhibition of bacterial DNA synthesis - bactericidal
In-vitro bactericidal effect on G- microorganisms
High concentrations in urine but low in blood and tissues
Mechanism of action of quinolones:
Inhibit replication of bacterial DNA by blocking the ligase domain of bacterial DNA gyrase (topoisomerase II); some also inhibit topoisomerase IV.
These enzymes relax DNA supercoils and enable DNA replication and repair
- Bactericidal
Mechanism of action of fluoroquinolones:
Inhibit two enzymes (DNA topoisomeres) involved in bacterial DNA synthesis.
Human cells lack these enzymes, and they are essential for bacterial DNA replication.
Both specific and bactericidal.
Indications of quinolones:
Urinary tract infections: acute cystitis, prevention of chronic infections
Enteric infections: shigellosis, bacterial enterocolitis
Indications of fluoroquinolones:
Upper respiratory tract infections
Enteric infections
Anthrax
Infections of the urogenital system
Infections of skin, soft tissues, bones and joints
Eye infections
Meningitis by G- bacteria
Sepsis
Tuberculosis
Division of quinolones:
4 generations:
1. gen - quinolones
2. - 4. gen. - fluoroquinolones
Name some quinolones:
nalidixid acid, oxalin acid, flumechin, cinoxacin, flumexil 5% inj a.u.v, flumigal 4% plv. a.u.v.
