Sulphonamides Cotrimoxazole And Quinolones
Question 1. Give a Description Of the Adverse Effects Of Sulfonamides.
Answer:
Sulfonamide is an antimicrobial drug.
The following are the adverse effects of sulfonamides:
- Presence of nausea, vomiting, and epigastric pain.
- Sulphonamide has acetylated products which are poorly soluble in acidic urine and can cause crystalluria, hematuria, and obstruction of the urinary tract.
- Hypersensitivity reactions, i.e. skin rashes, itching, drug fever, exfoliative dermatitis. Steven Johnson syndrome is the most severe type of hypersensitivity reaction.
- In patients with G6PD deficiency dose-dependent hemolysis occur which can cause acute hemolytic anemia.
- Kernicterus may be precipitated in newborns by displacement of bilirubin from plasma protein binding sites and a more permeable blood-brain barrier.
- Rare side effects are hepatitis and suppression of bone marrow.
Question 2. Comment On Cotrimoxazole.
Or
Write a Short Note On Cotrimoxazole.
Or
Write About the Mechanism Of Action Of Cotrimoxazole.
Or
Write Briefl On Cotrimoxazole.
Answer:
Cotrimoxazole is an antimicrobial drug.
- The fixed combination of trimethoprim and sulfamethoxazole is called cotrimoxazole.
Read And Learn More: Pharmacology Question And Answers
Cotrimoxazole Mechanism Of Action
Cotrimoxazole leads to sequential blockage, i.e. both sulfamethoxazole and trimethoprim interfere with two successive steps in the same metabolic pathway and their combination causes a supra-additive effect. Sulfamethoxazole causes inhibition of folate synthetase enzyme and trimethoprim causes inhibition of dihydrofolate reductase enzyme. Individually both the drugs are bacteriostatic but their combination is bacteriocidal. Cotrimoxazole acts by inhibiting the metabolism of folic acid.
Cotrimoxazole Adverse Effects
- Nausea, vomiting, headache, stomatitis, and rashes.
- There can be the presence of folate deficiency.
- Blood dyscrasias are very rare.
- If the drug is given during pregnancy there is neonatal hemolysis and methemoglobinemia.
- If the patient has renal disease the drug can lead to uremia.
- Presence of bone marrow hypoplasia, fever, and rashes if given in patients of AIDS.
- In elderly patients, there can be the presence of bone marrow toxicity.
Cotrimoxazole Therapeutic Uses
- Urinary tract infection: Cotrimoxazole is used in the treatment of acute uncomplicated lower urinary tract infection due to Gram-negative microorganisms. These drugs produce moderate activity against pseudomonas infection. Cotrimoxazole is also effective in cases of bacterial prostatitis.
- Respiratory tract infection: Cotrimoxazole is indicated in both acute and chronic bronchitis. It is also used in acute maxillary sinusitis and otitis media.
- Bacterial diarrhea: Cotrimoxazole is indicated in various gastrointestinal infections caused by Shigella, E. coli, and Salmonella species.
- Typhoid: Cotrimoxazole is used as an alternate drug in patients who can’t tolerate fluoroquinolones.
- Pneumocystis jiroveci infection: It is used both in the treatment and prophylaxis of P. jiroveci infection.
- Chancroid: Cotrimoxazole is effective in treating chancroid caused by H. ducreyi.
Question 3. Discuss The Advantages Of Sulfamethoxazole With Trimethoprim As Antimicrobial Agent.
Answer:
The sulfamethoxazole with Trimethoprim as an antimicrobial agent is known as cotrimoxazole.
Antimicrobial Agent Advantages
- In combination, both drugs produce bactericidal effects.
- The chances of bacterial resistance are very less.
- On oral administration, the drug is well absorbed.
- The drugs are widely distributed to the tissues of the body.
- The drug is highly potent.
Question 4. Write A Note On Fluoroquinolone Antimicrobial Drugs.
Or
Write In Short About Fluoroquinolone.
Or
Classify Fluoroquinolones. Write Their Mechanism Of Action, Uses, And Adverse Effects.
Answer:
Fluoroquinolones are quinolone antimicrobials with Florine substitutes.
Classifiation Of Fluoroquinolone
- Ist generation fluoroquinolone: Norflxacin, ciproflxacin, oflxacin and peflxacin.
- lInd generation fluoroquinolone: Lomeflxacin, sparflxacin, gatiflxacin, levoflxacin, moxiflxacin and amiflxacin
- IIIrd generation fluoroquinolone: Gemiflxacin, pruliflxacin.
Floroquinolone Mechanism Of Action
Floroquinolone Uses
- Respiratory tract infection: Fluoroquinolones are used in the treatment of both upper and lower respiratory tract infections. Newer fluoroquinolones are very effective in chronic bronchitis and community-acquired pneumonia.
- Urinary tract infections: Fluoroquinolones are the first choice drugs in the treatment of urinary tract infections. They are very effective against Gram-negative microorganisms.
- Bacterial diarrhea: These drugs are indicated in various gastrointestinal infections caused by E. coli, Shigella, and Salmonella. These drugs are also effective in traveler’s diarrhea.
- Typhoid: Ciprofloxacin is the first choice drug in the treatment of typhoid. It is given 750 mg orally BD for 10 days.
- Sexually transmitted diseases: Fluoroquinolones are effective in the treatment of chancroid, and gonococcal infections.
- Skin, soft tissue, and bone infections: Fluoroquinolones are very effective in infections caused due to S. aureus and Gram-negative bacteria. They are also used in diabetic foot infections.
- Neutropenic patients: They are given in both prophylaxis and treatment of infections in neutropenic patients.
- Conjunctivitis: Ciprofloxacin, levofloxacin, and ofloxacin are typically used.
- Mycobacterial infections: Fluoroquinolones are used in combination with other antibiotics.
Floroquinolone Adverse Effects
Gastrointestinal tract: Nausea, vomiting, abdominal discomfort.
Central nervous system: Dizziness, headache, insomnia, confusion, hallucination, and convulsion.
Hypersensitivity reactions: Skin rash, urticaria, itching, and photosensitivity.
Tendon rupture and tenosynovitis in athletes.
Question 5. Write A Short Note On Ciprofloxacin.
Or
Describe Ciprofloxacin.
Or
Describe The Therapeutic Uses Of Ciprofloxacin.
Answer:
Ciprofloxacin is a fist generation fluoroquinolones antimicrobial drug.
- It is active against Gram-negative bacilli, especially Enterobacteriaceae and Neisseria.
- It is highly susceptible to E. coli, N. meningitidis, Pneumonia, Salmonella, Shigella, Proteus, Enterobacter, etc.
- Ciprofloxacin has rapid bactericidal activity by digesting DNA.
- It has a low frequency of resistance.
Ciprofloxacin Pharmacokinetics
It is given orally, IV, or topically. Ciprofloxacin is well absorbed from the gut but if food is present in the gut, it delays the absorption. The drug is widely distributed in the body and reaches a high concentration in the kidney, lungs, prostate, bile, etc. It is excreted in the urine.
Ciprofloxacin Adverse Effects
- GIT: Nausea, vomiting, and abdominal discomfort
- CNS: Headache, dizziness, insomnia, confusion, hallucination, and convulsion
- Hypersensitivity reactions such as skin rashes, urticaria, itching, eosinophilia, and photosensitivity.
- Tendon rupture and tenosynovitis can occur especially in athletes.
Ciprofloxacin Therapeutic Uses
- Urinary tract infection: As ciprofloxacin is effective against Gram-negative bacilli, i.e. E. coli, Proteus, and Enterobacter it is given in the upper urinary tract. Ciprofloxacin is given 750 mg BD for three weeks in an upper urinary tract infection.
- Bacterial diarrhea: Ciprofloxacin is effective for E. coli, Shigella, Salmonella, etc. so it is given for 3 to 5 days.
- Typhoid fever: It is the first choice drug for typhoid fever. The drug is bactericidal and leads to fast resolution of symptoms.
- Chancroid: Ciprofloxacin should be given 500 mg BD for 3 days.
- In skin soft tissue and bone infections: Ciprofloxacin along with other antimicrobials is given in diabetic foot infections.
- In meningococcal infections: Ciprofloxacin eradicates meningococci from the nasopharynx and eliminates the carrier state.
- Tuberculosis: It is the component of chemotherapy for multidrug-resistant tuberculosis.
- Conjunctivitis: Ciprofloxacin is used topically in the treatment of conjunctivitis.
- Anthrax: It is the preferred drug for prophylaxis and treatment of anthrax.
Ciprofloxacin Drug Interactions
- Ciprofloxacin increases the plasma concentration of theophylline, warfarin, etc. by inhibiting their metabolism.
- NSAIDs can potentiate CNS side effects of ciprofloxacin.
- Antacids, ferrous sulfate, and sucralfate reduce the absorption of ciprofloxacin.
Question 6. Write A Short Note On Cotrimoxazole In Dentistry.
Answer:
Cotrimoxazole is an antimicrobial drug. It is a combination of trimethoprim and sulfamethoxazole.
Cotrimoxazole Mechanism Of Action
Cotrimoxazole leads to sequential blockage, i.e. both sulphamethoxazole and trimethoprim interfere with two successive steps in the same metabolic pathway and their combination causes a supra-additive effect.
Sulphamethoxazole causes inhibition of folate synthetase enzyme and trimethoprim causes inhibition of dihydrofolate reductase enzyme.
Individually both the drugs are bacteriostatic but their combination is bacteriocidal. Cotrimoxazole acts by inhibiting the metabolism of folic acid.
Cotrimoxazole Adverse Effects
- Nausea, vomiting, headache, stomatitis, and rashes.
- There can be the presence of folate deficiency.
- Blood dyscrasias are very rare.
- If a drug is given during pregnancy there is neonatal hemolysis and methemoglobinemia.
- If a patient has renal disease the drug can lead to uremia.
- Presence of bone marrow hypoplasia, fever, and rashes if
given in patients of AIDS. - In elderly patients, there can be the presence of bone marrow toxicity.
Cotrimoxazole Uses
- It is used in the odontogenic infections.
- It is used in periodontal diseases.
- It is occasionally used for oriental infections and may be an alternative drug for patients allergic to β lactam antibiotics.
Question 7. Write A Short Note On The Sequential Block.
Answer:
A fixed-dose combination of trimethoprim and sulfamethoxazole is called co-trimoxazole.
- Cotrimoxazole is introduced in 1969 causing a sequential block of folate metabolism. Trimethoprim is 50,000 times more active against bacterial dihydrofolate reductase than against mammalian enzymes.
- Individually both sulfonamide and trimethoprim are bacteriostatic but the combination becomes tidal against many organisms, hence the combination of both drugs causes bacteriocidal action and is used in both gram-positive and gram-negative actions.
- Sulfonamide stops the folate synthesis of the bacterial cell membrane and trimethoprim causes the formation of dihydrofolate reductase and causes the formation of trihydrofolic acid which cause a sequential block in bacterial folate metabolism.
Question 8. Enumerate The Adverse Effects Of Cotrimoxazole.
Answer:
The following are the adverse effects of cotrimoxazole:
Cotrimoxazole Adverse Effects
- Nausea, vomiting, headache, stomatitis, and rashes.
- There can be the presence of folate deficiency.
- Blood dyscrasias are very rare.
- If the drug is given during pregnancy there is neonatal hemolysis and methemoglobinemia.
- If the patient has renal disease the drug can lead to uremia.
- Presence of bone marrow hypoplasia, fever, and rashes if given in patients of AIDS.
- In elderly patients, there can be the presence of bone marrow toxicity.
Question 9. Write A Short Note On Levofloxacin.
Answer:
It is a second-generation fluoroquinolone.
It is the levoisomer of ofloxacin having improved activity against Streptococcus pneumoniae and some other gram-positive and gram-negative bacteria.
Levofloxacin Mechanism Of Action
These drugs block bacterial DNA synthesis by inhibiting bacterial topoisomerase II and topoisomerase IV.
Inhibition of topoisomerase II prevents the relaxation of positively supercoiled DNA that is required for normal transcription and replication.
While inhibition of topoisomerase IV probably interferes with the separation of replicated chromosomal DNA into respective daughter cells during cell division.
Levofloxacin Pharmacokinetics
Levofloxacin has almost 100% oral bioavailability.
Levofloxacin Indications
- The primary indication of levofloxacin is community-acquired pneumonia and exacerbations of chronic bronchitis.
- In sinusitis
- In enteric fever
- In pyelonephritis
- In skin/soft tissue infections.
Question 10. Explain Why Sulphamethoxazole And Trimethoprim Are Used In Combination.
Answer:
The fixed combination of trimethoprim and sulfamethoxazole is called cotrimoxazole. Sulfamethoxazole and trimethoprim as individual drugs act as bacteriostatic drugs but in combination, they act as bacteriocidal.
- Cotrimoxazole acts by inhibiting the metabolism of folic acid.
- Trimethoprim selectively inhibits bacterial dihydrofolate reductase whereas sulphamethoxazole inhibits the conversion of PABA to dihydrofolate.
Question 11. Name Four Fluoroquinolones, Indications, And Adverse Effects For AnyOne.
Answer:
Four Fluoroquinolones
- Ciprofloxacin
- Norfloxacin
- Ofloxacin
- Levofloxacin
Indications Of Ciprofloxacin
- Urinary tract infection: As ciprofloxacin is effective against Gram-negative bacilli, i.e. E. coli, Proteus, and Enterobacter it is given in the upper urinary tract. Ciprofloxacin is given 750 mg BD for three weeks in an upper urinary tract infection.
- Bacterial diarrhea: Ciprofloxacin is effective for E. coli, Shigella, Salmonella, etc., so it is given for 3 to 5 days.
- Typhoid fever: It is the first choice drug for typhoid fever. The drug is bactericidal and leads to fast resolution of symptoms.
- Chancroid: Ciprofloxacin should be given 500 mg BD for 3 days.
- In skin soft tissue and bone infections: Ciprofloxacin along with other antimicrobials is given in diabetic foot infections.
- In meningococcal infections: Ciprofloxacin eradicates meningococci from the nasopharynx and eliminates the carrier state.
- Tuberculosis: It is the component of chemotherapy for multidrug-resistant tuberculosis.
- Conjunctivitis: Ciprofloxacin is used topically in the treatment of conjunctivitis.
- Anthrax: It is the preferred drug for prophylaxis and treatment of anthrax.
Adverse Effects Of Ciprofloxacin
- Gastrointestinal tract: Nausea, vomiting, abdominal discomfort.
- Central nervous system: Dizziness, headache, insomnia, confusion, hallucination, and convulsion.
- Hypersensitivity reactions: Skin rash, urticaria, itching, and photosensitivity.
- Tendon rupture and tenosynovitis in athletes.
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