Aminosalicylates or aminosalicylic acid is used with other drugs to treat tuberculosis. Aminosalicylic acid is thought to inhibit folic acid synthesis and/or inhibit synthesis of a component of the cell wall.
What is folic acid synthesis inhibitor?
Folic Acid Synthesis Inhibitors. Folic acid enzymes are necessary for the synthesis of Amino acids, hence necessary for bacterial protein synthesis. We shall be discussing some drugs which interfere with the synthesis of folic acid at different levels and prevent / inhibit growth of micro-organisms.
What class of antibiotics interfere with the synthesis of folic acid?
Folic acids are the enzymes that are necessary for the bacterial protein synthesis and synthesis of amino acids. Trimethoprim and Sulfonamides are the antimicrobial classes that interfere with the synthesis of folic acid at different levels and are bacteriostatic.
What is the role of folic acid in bacterial protein synthesis?
Folic acid enzymes are necessary for the synthesis of Amino acids, hence necessary for bacterial protein synthesis. We shall be discussing some drugs which interfere with the synthesis of folic acid at different levels and prevent / inhibit growth of micro-organisms.
What are some drugs that are anti folate?
Such drugs include some anticonvulsants ( valproic acid, carbamazepine, phenobarbital, phenytoin, and primidone) and trimethoprim. Lamotrigine is also an anticonvulsant with known (from in vitro testing) weak anti-folate effects. Sulfonamides, a class of antimicrobials that work by inhibiting folate biosynthesis.
Is c. effective only if given intravenously?
c. are effective only if given intravenously.
Is erythromycin a good substitute for penicillin?
When patients are allergic to penicillin, erythromy cin has proven to be an effective alternative.
Is aminoglycoside bacteriostatic?
Aminoglycosides are an example of antiinfectives that are classified as bacteriostatic.
Is cephalosporin bactericidal or bacteriostatic?
Cephalosporins can be classified as either bactericidal or bacteriostatic depending on which specific drug and dose are used.
What prevents the HIV-1 virus from entering the cell?
What prevents the HIV-1 virus from entering the cell by stopping fusion of the virus with the human cellular membrane.
Is erythromycin a good substitute for penicillin?
When patients are allergic to penicillin, erythromy cin has proven to be an effective alternative.
Can antifungal agents be tolerated?
True or false; systemic antifungal agents are easily tolerated by patients with a low risk of toxicity.
Can fluuonazole be used as a prophylactic agent?
True or false; Fluuonazole (Diflucan) can be used as a prophylactic agent for reducing the incidence of candidiasis in bone marrow transplant recipients.
What are Aminosalicylates?
Aminosalicylates or aminosalicylic acid is used with other drugs to treat tuberculosis. Aminosalicylic acid is thought to inhibit folic acid synthesis and/or inhibit synthesis of a component of the cell wall. It is bacteriostatic against Mycobacterium tuberculosis.
Further information
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Fluoroquinolones: ciprofloxacin (Cipro), levofloxacin
Fluoroquinolones, including ciprofloxacin and levofloxacin are antibiotics used to treat a number of bacterial infections, including urinary tract infections (UTIs), bone and joint infections, respiratory infections, and anthrax.
Antiprotozoal: metronidazole (Flagyl)
Metronidazole is another common antibiotic administered in the hospital setting. It can be used for bacterial infections and protozoan infections.
Full Transcript
Hi, I am Cathy, with Level Up RN. In this video, I'm going to continue my coverage of antibiotics. In our last two videos, we talked about antibiotics that affect protein synthesis and cell wall synthesis. In this video, we are going to talk about antibiotics that affect the bacterial cell in other ways.
What is the name of the drug that antagonizes folate?
Drugs that incidentally antagonize folate. The name antifolate usually refers to drugs whose folate antagonism is intentional. In contrast, there are some other drugs, of several drug classes, that antagonize folate incidentally, as an adverse effect, whether mildly or heavily.
What is the function of folic acid?
Folic acid's primary function in the body is as a cofactor to various methyltransferases involved in serine, methionine, thymidine and purine biosynthesis. Consequently, antifolates inhibit cell division, DNA/RNA synthesis and repair and protein synthesis.
What is the class of antimetabolite medications?
Class of antimetabolite medications. Dihydrofolate reductase (DHFR) Folic acid. Antifolates are a class of antimetabolite medications that antagonise (that is, block) the actions of folic acid (vitamin B 9 ). Folic acid's primary function in the body is as a cofactor to various methyltransferases involved in serine, methionine, ...
What drugs can cause neural tube defects?
Such drugs include some anticonvulsants ( valproic acid, carbamazepine, phenobarbital, phenytoin, and primidone) and trimethoprim.
Does methotrexate reduce DHF?
In response to decreased tetrahydrofolate (THF), the cell begins to transcribe more DHF reductase, the enzyme that reduces DHF to THF. Because methotrexate is a competitive inhibitor of DHF reductase, increased concentrations of DHF reductase can overcome the drugs inhibition.
Is antifolate bad for your skin?
The antifolate action specifically targets the fast-dividing cells, and tend to have adverse effects on the bone marrow, skin, and hair. As folate is vital in the first trimester of pregnancy for healthy fetal development, the use of antifolates is strongly contraindicated in pregnancy and carries significant teratogenic risk.
Is antifolate cytotoxic?
Antifolates act specifically during DNA and RNA synthesis, and thus are cytotoxic during the S-phase of the cell cycle. Thus, they have a greater toxic effect on rapidly dividing cells (such as malignant and myeloid cells, and GI & oral mucosa), which replicate their DNA more frequently, and thus inhibits the growth and proliferation of these non-cancerous cells as well as causing the side-effects listed.
What antibacterial drugs bind to the 30S subunit?
Another class of antibacterial compounds that bind to the 30S subunit is the tetracyclines. In contrast to aminoglycosides, these drugs are bacteriostatic and inhibit protein synthesis by blocking the association of tRNAs with the ribosome during translation. Naturally occurring tetracyclines produced by various strains of Streptomyces were first discovered in the 1940s, and several semisynthetic tetracyclines , including doxycycline and tigecycline have also been produced. Although the tetracyclines are broad spectrum in their coverage of bacterial pathogens, side effects that can limit their use include phototoxicity, permanent discoloration of developing teeth, and liver toxicity with high doses or in patients with kidney impairment.
Which family of drugs is used to treat Gram positive and Gram negative bacteria?
In contrast, the carbapenem family includes a variety of semisynthetic drugs (imipenem, meropenem, and doripenem) that provide very broad-spectrum activity against gram-positive and gram-negative bacterial pathogens.
What are the characteristics of antibacterial compounds?
Key Concepts and Summary 1 Antibacterial compounds exhibit selective toxicity, largely due to differences between prokaryotic and eukaryotic cell structure. 2 Cell wall synthesis inhibitors, including the β-lactams, the glycopeptides, and bacitracin, interfere with peptidoglycan synthesis, making bacterial cells more prone to osmotic lysis. 3 There are a variety of broad-spectrum, bacterial protein synthesis inhibitors that selectively target the prokaryotic 70S ribosome, including those that bind to the 30S subunit ( aminoglycosides and tetracyclines) and others that bind to the 50S subunit ( macrolides, lincosamides, chloramphenicol, and oxazolidinones ). 4 Polymyxins are lipophilic polypeptide antibiotics that target the lipopolysaccharide component of gram-negative bacteria and ultimately disrupt the integrity of the outer and inner membranes of these bacteria. 5 The nucleic acid synthesis inhibitors rifamycins and fluoroquinolones target bacterial RNA transcription and DNA replication, respectively. 6 Some antibacterial drugs are antimetabolites, acting as competitive inhibitors for bacterial metabolic enzymes. Sulfonamides and trimethoprim are antimetabolites that interfere with bacterial folic acid synthesis. Isoniazid is an antimetabolite that interferes with mycolic acid synthesis in mycobacteria.
How do antibacterial drugs work?
Some antibacterial drugs work by inhibiting nucleic acid synthesis (Table 14.3. 5 ). For example, metronidazole is a semisynthetic member of the nitroimidazole family that is also an antiprotozoan. It interferes with DNA replication in target cells. The drug rifampin is a semisynthetic member of the rifamycin family and functions by blocking RNA polymerase activity in bacteria. The RNA polymerase enzymes in bacteria are structurally different from those in eukaryotes, providing for selective toxicity against bacterial cells. It is used for the treatment of a variety of infections, but its primary use, often in a cocktail with other antibacterial drugs, is against mycobacteria that cause tuberculosis. Despite the selectivity of its mechanism, rifampin can induce liver enzymes to increase metabolism of other drugs being administered (antagonism), leading to hepatotoxicity (liver toxicity) and negatively influencing the bioavailability and therapeutic effect of the companion drugs.
What is bacitracin used for?
Bacitracin is effective against a wide range of bacteria, including gram-positive organisms found on the skin, such as Staphylococcus and Streptococcus. Although it may be administered orally or intramuscularly in some circumstances, bacitracin has been shown to be nephrotoxic (damaging to the kidneys). Therefore, it is more commonly combined with neomycin and polymyxin in topical ointments such as Neosporin.
How do synthetic drugs work?
Some synthetic drugs control bacterial infections by functioning as antimetabolites, competitive inhibitors for bacterial metabolic enzymes (Table 14.3. 6 ). The sulfonamides (sulfa drugs) are the oldest synthetic antibacterial agents and are structural analogues of para -aminobenzoic acid (PABA), an early intermediate in folic acid synthesis (Figure 14.3. 4 ). By inhibiting the enzyme involved in the production of dihydrofolic acid, sulfonamides block bacterial biosynthesis of folic acid and, subsequently, pyrimidines and purines required for nucleic acid synthesis. This mechanism of action provides bacteriostatic inhibition of growth against a wide spectrum of gram-positive and gram-negative pathogens. Because humans obtain folic acid from food instead of synthesizing it intracellularly, sulfonamides are selectively toxic for bacteria. However, allergic reactions to sulfa drugs are common. The sulfones are structurally similar to sulfonamides but are not commonly used today except for the treatment of Hansen’s disease (leprosy).
Why is penicillin a selective toxicity?
Because human cells do not make peptidoglycan, this mode of action is an excellent example of selective toxicity. Penicillin, the first antibiotic discovered, is one of several antibacterials within a class called β-lactams.