Antibiotics: Aminoglycosides

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Questions and Answers

What is the primary therapeutic action of aminoglycosides like Gentamicin?

Promote the replication of Gram-negative bacteria

Inhibit cell wall synthesis in Gram-positive bacteria

Disrupt DNA synthesis in all bacterial types

Inhibit protein synthesis in Gram-negative bacteria (correct)

Which condition is a contraindication for the use of Gentamicin?

Known allergy to aminoglycosides (correct)

Chronic obstructive pulmonary disease

Diabetes mellitus

Hypertension

What potential adverse effect is associated with the use of Gentamicin?

Thrombocytopenia

Nephrotoxicity (correct)

Cardiomyopathy

Skin hyperpigmentation

When administering Gentamicin with potent diuretics, which risk is increased?

Increased incidence of nephrotoxicity Signup and view all the answers

In what timeframe does Gentamicin reach its peak concentration when administered via IV?

30-90 minutes Signup and view all the answers

What is the primary action of carbapenems like ertapenem?

Bactericidal action that inhibits cell membrane synthesis Signup and view all the answers

For which of the following infections is ertapenem indicated?

Skin-and-skin structure infections Signup and view all the answers

What is a common adverse effect associated with carbapenems?

Headache Signup and view all the answers

What should be monitored in patients receiving ertapenem?

Urine function Signup and view all the answers

Which condition is a contraindication for using carbapenems?

Seizure disorders Signup and view all the answers

What is the peak time for ertapenem when given IV or IM?

30-120 minutes Signup and view all the answers

What class of antibiotics does cephalor belong to?

Cephalosporins Signup and view all the answers

What is a potential drug-drug interaction when using cephalosporins?

Increased risk of nephrotoxicity with aminoglycosides Signup and view all the answers

Which regimen is considered the safest for pregnant patients requiring treatment?

Isoniazid, ethambutol, and rifampin Signup and view all the answers

What should be monitored closely when rifampin is combined with other medications?

Liver enzyme levels Signup and view all the answers

What is a potential adverse effect of the drug regimen including isoniazid?

Liver toxicity Signup and view all the answers

Which combination of conditions contraindicates the use of telithromycin?

Known congenital prolonged QT interval and bradycardia Signup and view all the answers

What is a common adverse effect associated with telithromycin?

Headache Signup and view all the answers

What is the therapeutic action of telithromycin?

Binds to bacterial ribosomes Signup and view all the answers

Which drug interaction should be avoided with telithromycin?

Pimozide Signup and view all the answers

In which condition should caution be exercised when using telithromycin?

Pregnancy and lactation Signup and view all the answers

What is a possible serious reaction to consuming alcohol after taking this medication?

Disulfiram-like reaction Signup and view all the answers

What therapeutic action do fluoroquinolones like ciprofloxacin primarily demonstrate?

Interference with DNA replication Signup and view all the answers

Which of the following conditions is a contraindication for taking fluoroquinolones?

Allergy to the drug Signup and view all the answers

What should be monitored when patients are on oral anticoagulants combined with cephalosporins?

Blood loss signs Signup and view all the answers

What is the peak time for IV ciprofloxacin after administration?

30 minutes Signup and view all the answers

What is one of the cautionary considerations regarding fluoroquinolones?

Presence of renal dysfunction Signup and view all the answers

Which of the following adverse effects is associated with fluoroquinolones?

Rash Signup and view all the answers

When should two drugs that interact with fluoroquinolones be administered if they must be used together?

4 hours apart Signup and view all the answers

What are the therapeutic actions of sulfonamides?

Block two consecutive steps in protein and nucleic acid production Signup and view all the answers

Which of the following conditions is NOT indicated for the use of cotrimoxazole?

Stomach ulcers Signup and view all the answers

What is a common adverse effect associated with sulfonamides?

Hepatocellular necrosis Signup and view all the answers

Which drugs pose a risk of increased hypoglycemia when combined with sulfonamides?

Sulfonylureas Signup and view all the answers

What are cautions related to the use of sulfonamides in patients?

Kidney disease or history of kidney stones Signup and view all the answers

What is the peak absorption time for sulfamethoxazole and trimethoprim when taken orally?

1-4 hours Signup and view all the answers

Which of the following statements about aminoglycosides and penicillins is correct?

Aminoglycosides can inactivate penicillins when combined Signup and view all the answers

Which of these effects are caused by tetracycline?

Inhibits protein synthesis in bacteria Signup and view all the answers

Study Notes

Aminoglycosides - Gentamicin

Bactericidal agent effective against serious Gram-negative aerobic bacilli infections.
Mechanism: Inhibits protein synthesis and irreversibly binds to bacterial ribosomes, causing misreading of genetic code and cell death.
Indicated for pseudomonas and various other Gram-negative infections.
Administration: IM or IV route with rapid onset; peak effect occurs within 30-90 mins and half-life of 2-3 hours, metabolized in the liver.
Contraindications include known allergies, renal/hepatic disease, hearing loss, active herpes/mycobacterial infections, and specific neuromuscular conditions.
Use caution in pregnancy; frequent urine function tests are necessary due to kidney excretion.
High risk of nephrotoxicity and ototoxicity; use amikacin only if essential.
Adverse effects include sinusitis, dizziness, rash, fever, and potential nephrotoxicity.
Drug interactions: Synergistic with penicillins/cephalosporins; avoid potent diuretics and certain anesthetics to prevent increased neuromuscular blockade.

Carbapenems - Ertapenem

Bactericidal antibiotic targeting cell membrane synthesis in susceptible bacteria.
Used for community-acquired pneumonia, complex GU and intra-abdominal infections, and skin infections.
Administered IV/IM once daily; rapid onset with peak in 30-120 mins, half-life of 4 hours, and excreted unchanged in urine.
Contraindications include known allergies, seizure disorders, and meningitis; caution in pregnancy and renal function monitoring is essential.
Adverse effects may include headache, dizziness, nausea, vomiting, pseudomembranous colitis, and injection site pain.
Careful consideration required when used alongside valproic acid to avoid decreased serum levels and increased seizure risk.

Cephalosporins - Cefaclor

Inhibits bacterial cell wall synthesis resulting in cell death.
Indicated for respiratory infections, UTIs, otitis media, and typhoid fever.
Administered orally; peak effect achieved in 20-60 mins, duration of action is 8-10 hours, half-life of 30-60 mins.
Contraindications include allergies to cephalosporins/penicillins due to cross-sensitivity; caution advised for liver or kidney impairment and in pregnancy/lactation.
Possible adverse effects include nausea, vomiting, diarrhea, rash, and risk of colitis.
Drug interactions: Increased nephrotoxicity risk when used with aminoglycosides, and can enhance anticoagulant effects leading to bleeding.

Fluoroquinolones - Ciprofloxacin

Disrupts DNA replication in Gram-negative bacteria, inhibiting cell reproduction.
Treats respiratory, dermatological infections, typhoid fever, and post-anthrax exposure.
Available orally and IV; peak effect varies (60-90 mins orally; 30 mins IV) with half-life of 3.5-4 hours.
Contraindications include allergy to the drug, pregnancy, and renal dysfunction.
Adverse effects include headache, dizziness, nausea, hypotension, and rash.
Drug interactions: Reduced effectiveness with certain antacids and supplements; caution with drugs that increase QTc interval and parenteral penicillins.

Sulfonamides - Cotrimoxazole

Inhibits two consecutive steps in protein and nucleic acid synthesis, preventing cellular multiplication.
Indicated for UTIs and pneumonia caused by susceptible strains.
Combination of sulfamethoxazole and trimethoprim administered orally; rapidly absorbed, peak effect in 1-4 hrs.
Contraindications: Allergies to sulfonamides, pregnancy, and certain diuretics; caution in patients with renal disease.
Adverse effects include gastrointestinal disturbances, bone marrow suppression, and skin reactions.
Drug interactions: Increased hypoglycemia risk with antidiabetic medications and nephrotoxic risk when combined with cyclosporine.

Tetracycline

Inhibits protein synthesis in bacteria, potentially toxic at high concentrations.
Caution advised in pregnancy; safer alternatives may include isoniazid.
Adverse effects include peripheral neuropathy, gastrointestinal issues, and liver toxicity.
Drug interactions: Increased liver toxicity risk when combined with certain antibiotics; decreased effectiveness when combined with rifampin or rifabutin.

Ketolides - Telithromycin

Binds bacterial ribosomes altering protein function, leading to cell death.
Effective against resistant strains of bacteria; approved for community-acquired pneumonia treatment.
Administered orally with rapid onset; peak at 0.5-4 hours and half-life of 10 hours.
Contraindications include allergies and known prolonged QT interval or certain arrhythmias; use caution in liver/kidney impairments.
Adverse effects: Headache, dizziness, gastrointestinal disturbances, and superinfections.
Drug interactions: Avoid with certain statins and antiarrhythmics due to risk of serious adverse effects.

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Description

This quiz focuses on the antibiotic Gentamicin, a bactericidal agent effective against serious infections caused by Gram-negative bacteria. It explores therapeutic actions, pharmacokinetics, and the specific indications for use, including pseudomonas infections.

Antibiotics: Aminoglycosides - Gentamicin

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