Topical Antibiotics: Bacitracin and Polymyxin B

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary mechanism by which topical beta-blockers lower intraocular pressure (IOP)?

Increasing the outflow of aqueous humor

Decreasing the production of aqueous humor (correct)

Absorbing intraocular fluid

Enhancing systemic circulation

Which of the following is a common side effect of topical beta-blockers?

Dry eyes (correct)

Elevated blood pressure

Hypotension

Increased heart rate

In which condition is the use of topical beta-blockers contraindicated?

Atrioventricular (AV) heart block (correct)

Hypertension

Asthma

Diabetes mellitus

What cautionary measure should be taken when prescribing topical beta-blockers?

In patients with heart failure Signup and view all the answers

Which interaction should be considered when prescribing topical beta-blockers?

Systemic beta blockers Signup and view all the answers

Which population group is at increased risk for aortic aneurysm when using certain medications?

Elderly individuals Signup and view all the answers

What is a known risk associated with ciprofloxacin?

QT prolongation Signup and view all the answers

What adverse effects are associated with sulfacetamide when used topically?

Local irritation, stinging and burning Signup and view all the answers

Sulfacetamide is primarily used for treating which condition?

Conjunctivitis and other ocular infections Signup and view all the answers

What is a primary mechanism of erythromycin's action?

Inhibits protein synthesis Signup and view all the answers

Which of the following is true regarding the use of topical medications with patients on glucocorticoids?

Caution advised due to potential interactions Signup and view all the answers

What condition has been reported to develop during treatment with sulfonamide ophthalmic preparations?

Corneal ulcers Signup and view all the answers

Which of the following is a contraindication for the use of erythromycin?

History of hypersensitivity Signup and view all the answers

What caution should be taken into account when prescribing erythromycin?

Potential for superinfection or overgrowth Signup and view all the answers

Which aspect of folate metabolism is inhibited by sulfacetamide?

Folate synthesis Signup and view all the answers

What risk is associated with ofloxacin usage?

Possible risk of QT prolongation Signup and view all the answers

Erythromycin can increase the plasma levels of which of the following medications?

Warfarin Signup and view all the answers

What can erythromycin antagonize in its antibiotic action?

Clindamycin Signup and view all the answers

What is the risk involved with drug-to-drug interactions when using erythromycin?

Increased toxicity of interacting drugs Signup and view all the answers

Which of the following bacteria would erythromycin most effectively target?

Bacteria susceptible to erythromycin Signup and view all the answers

What is a potential consequence of erythromycin use in patients undergoing treatment for other conditions?

Superinfection of treated infections Signup and view all the answers

What primary mechanism does bacitracin use to exert its bactericidal effect?

Inhibition of peptidoglycan synthesis Signup and view all the answers

Which types of organisms is bacitracin effective against?

Both gram-positive and gram-negative organisms Signup and view all the answers

What is a reported adverse effect associated with the topical use of erythromycin?

Minor ocular irritations Signup and view all the answers

What component of the bacterial cell membrane does bacitracin interact with?

Phospholipid components Signup and view all the answers

Which of the following statements about erythromycin is true?

It controls the development or reproduction of bacteria by inhibiting protein synthesis. Signup and view all the answers

What is the primary purpose of bacitracin as an antibiotic?

Bactericidal action through cell wall interference Signup and view all the answers

Why should erythromycin be used with caution during pregnancy and lactation?

There is insufficient data on its safety. Signup and view all the answers

Which conditions might result in QT prolongation when using certain antibiotics?

HIV protease inhibitors and beta-blockers Signup and view all the answers

What type of reactions may occur as adverse effects of bacitracin?

Hypersensitivity reactions Signup and view all the answers

What is the mechanism of action of fluoroquinolone antibiotics like ofloxacin?

Interfering with DNA gyrase Signup and view all the answers

Which of the following is a reported adverse effect of ofloxacin ophthalmic drops?

Transient ocular burning Signup and view all the answers

In which patient scenario should ofloxacin not be used due to contraindications?

Patients with a history of hypersensitivity to other quinolones Signup and view all the answers

What type of infections are treated with ofloxacin ophthalmic drops?

Bacterial conjunctivitis and corneal ulcers Signup and view all the answers

What is a rare adverse effect associated with ofloxacin ophthalmic use?

Dizziness Signup and view all the answers

Which of the following statements regarding the use of ofloxacin during pregnancy is correct?

Not enough data is available to determine its safety. Signup and view all the answers

What type of symptoms can be experienced with ofloxacin use other than ocular issues?

Nausea and dizziness Signup and view all the answers

What is the primary indication for using Bacitracin-polymyxin B ophthalmic ointment?

Topical treatment of superficial infections of the external eye Signup and view all the answers

Which mechanism of action is associated with Neomycin?

Inhibits protein synthesis Signup and view all the answers

What is a common side effect associated with the use of Neomycin ophthalmic preparations?

Itching and swelling Signup and view all the answers

Which of the following is a major safety consideration when using Bacitracin-polymyxin B?

Potential for anaphylaxis in sensitive individuals Signup and view all the answers

What should be considered when prescribing Neomycin?

Avoid use in individuals with hypersensitivity to its components Signup and view all the answers

How does Bacitracin-polymyxin B demonstrate its bactericidal properties?

By binding to ribosomes and inhibiting protein synthesis Signup and view all the answers

Which statement about the use of Neomycin in pregnancy or lactation is accurate?

There is insufficient data to confirm safety. Signup and view all the answers

What is a rare but serious side effect of extended use of Neomycin?

Hearing loss Signup and view all the answers

Study Notes

Antibiotics (Topical) - Polypeptide Antibiotics

Bacitracin-polymyxin B 0.1% ointment/drops: Indicated for superficial external eye infections caused by susceptible bacteria.
Mechanism of Action (MOA): Neomycin is bactericidal against Gram-positive and Gram-negative organisms. It inhibits protein synthesis by binding to ribosomal RNA, causing errors in protein production. Polymyxin B is bactericidal for a variety of Gram-negative organisms. It increases bacterial cell membrane permeability.
Safety Considerations/Contraindications: Individuals with hypersensitivity to the components should avoid use.
Adverse Effects: Itching, swelling, conjunctival erythema, and hypersensitivity reactions (including anaphylaxis), and rare local irritation are possible side effects.
Drug Interactions (D2D): No significant interactions noted.
Black Box Warning (BBW): Not noted.
Pregnancy/Lactation: Insufficient data to recommend safe use.

Antibiotics (Topical) - Macrolides

Erythromycin 0.5%: Treats superficial Gram-positive & some Gram-negative ocular infections involving conjunctivae and corneas
Mechanism of Action (MOA): Controls the development/reproduction of bacteria by inhibiting protein synthesis.
Safety Considerations/Contraindications: Patients with a history of Erythromycin hypersensitivity should not use.
Adverse Effects: Minor ocular irritations like redness and hypersensitivity reactions.
Drug Interactions (D2D): Erythromycin can increase plasma levels and half-lives of other drugs, potentially increasing toxicity.
Black Box Warning (BBW): Not noted.
Pregnancy/Lactation: Use with caution; insufficient data.

Antibiotics (Topical) - Fluoroquinolones

Ofloxacin 0.3% ophthalmic drops and Ciprofloxacin 0.3% ophthalmic drops: Treat bacterial conjunctivitis and corneal ulcers
Mechanism of Action (MOA): Interferes with bacterial DNA gyrase, stopping DNA replication and bacterial growth.
Safety Considerations/Contraindications: Patients with a history of hypersensitivity to these or other quinolones should avoid.
Adverse Effects: Transient ocular burning or discomfort; rare redness, itching, stinging possible.
Drug Interactions (D2D): Interactions with other drugs, potentially increasing toxicity.
Black Box Warning (BBW): Not noted.
Pregnancy/Lactation: Insufficient data.

Antibiotics (Topical) - Sulfonamides

Sulfacetamide (Bleph-10): Treats conjunctivitis, superficial ocular infections caused by susceptible microorganisms.
Mechanism of Action (MOA): Inhibits bacterial folate metabolism, impeding their growth. Also adjunctive in systemic therapy for trachoma.
Safety Considerations/Contraindications: Not noted.
Adverse Effects: Bacterial and fungal corneal ulcers in some cases, local irritation, stinging & burning, conjunctivitis, and allergic reactions.
Drug Interactions (D2D): Not noted.
Black Box Warning (BBW): Not noted.
Pregnancy/Lactation: Insufficient data

Topical Beta-Blockers

Timolol (Timoptic): and Betaxolol (Betoptic): Treats glaucoma.
Mechanism of Action (MOA): Lowers intraocular pressure by decreasing aqueous humor production.
Safety Considerations/Contraindications: Patients with AV heart block, sinus bradycardia, cardiogenic shock, or heart failure must use with caution.
Adverse Effects: Transient ocular stinging, conjunctivitis, blurred vision, redness, dryness, and some heart-related issues possible.
Drug Interactions (D2D): Interaction with Sulfacetamide and silver-containing preparations.
Black Box Warning (BBW): None mentioned.
Pregnancy/Lactation: Refer to a specialist.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz focuses on the topical polypeptide antibiotics, specifically Bacitracin and Polymyxin B. It covers their mechanism of action, safety considerations, adverse effects, and drug interactions. Enhance your knowledge about these antibiotics used for treating superficial external eye infections.