Usage
Mupirocin is a topical antibiotic primarily used for the treatment of impetigo, a highly contagious bacterial skin infection caused by Staphylococcus aureus and Streptococcus pyogenes. It is also effective against other bacterial skin infections such as folliculitis, furunculosis, and secondarily infected traumatic skin lesions. Its pharmacological classification is antibiotic.
Mupirocin’s mechanism of action involves inhibiting bacterial protein synthesis by selectively and reversibly binding to bacterial isoleucyl transfer-RNA synthetase. This action prevents the incorporation of isoleucine into bacterial proteins, leading to bacterial growth inhibition and cell death.
Alternate Names
Mupirocin is also known as pseudomonic acid A. Brand names include Bactroban, Centany, and Pirnuo.
How It Works
Pharmacodynamics: Mupirocin exerts its antibacterial effect by blocking protein synthesis in susceptible bacteria. This leads to bacterial stasis (inhibition of growth and replication) at lower concentrations and bactericidal action (killing of bacteria) at higher concentrations.
Pharmacokinetics: Topical application results in minimal systemic absorption through intact skin (less than 1%). Damaged skin may enhance absorption, but mupirocin applied under occlusive dressings doesn’t show significant systemic penetration. Any systemically absorbed mupirocin is rapidly metabolized in the liver to the inactive metabolite, monic acid. Monic acid is then excreted primarily through the kidneys. Mupirocin’s elimination half-life is approximately 20-40 minutes, while monic acid’s half-life is 30-80 minutes.
Mode of Action: Mupirocin binds specifically and reversibly to bacterial isoleucyl transfer-RNA synthetase. This enzyme is essential for incorporating the amino acid isoleucine during bacterial protein synthesis. By binding to this enzyme, mupirocin effectively halts protein synthesis in bacteria, leading to growth inhibition or cell death.
Elimination Pathways: While the primary elimination route for systemically absorbed mupirocin (after hepatic metabolism to monic acid) is renal excretion, most topically applied mupirocin is eliminated through the natural shedding of skin cells.
Dosage
Standard Dosage
Adults: Apply a small amount of mupirocin ointment or cream to the affected area 2-3 times daily for up to 10 days. The area may be covered with a gauze dressing, if needed.
Children:
- 2 months and older: Apply a small amount of 2% mupirocin ointment or cream to the affected area 2-3 times daily for up to 10 days.
- Under 2 months: Use with caution and only under the direction of a physician, as safety and efficacy have not been fully established in this age group.
Special Cases:
- Elderly Patients: No dosage adjustments are typically required.
- Patients with Renal Impairment: Use with caution. Dosage adjustment may be necessary in cases of severe renal impairment.
- Patients with Hepatic Dysfunction: No dosage adjustments are typically required due to minimal systemic absorption.
- Patients with Comorbid Conditions: Generally, no specific adjustments are needed, but individual patient factors should be considered.
Clinical Use Cases
Mupirocin is not indicated for use in clinical scenarios like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. It is intended for topical use on skin infections.
Dosage Adjustments
Dose adjustments might be necessary in patients with severe renal impairment. Consult product-specific guidelines and consider individual patient factors.
Side Effects
Common Side Effects:
Burning, stinging, itching, or dryness at the application site, rash, and nausea.
Rare but Serious Side Effects:
Severe allergic reactions (e.g., angioedema, urticaria, generalized rash), severe skin irritation or contact dermatitis.
Long-Term Effects:
Fungal or bacterial superinfection with prolonged use.
Adverse Drug Reactions (ADR):
Severe allergic reactions require immediate medical attention.
Contraindications
Known hypersensitivity to mupirocin or any of its components.
Drug Interactions
No clinically significant drug interactions are known with topical mupirocin due to its minimal systemic absorption. However, inform healthcare providers about all other medications, including topical products, being used concurrently.
Pregnancy and Breastfeeding
Topical mupirocin is generally considered safe during pregnancy and breastfeeding due to minimal systemic absorption. However, it’s advisable to consult with a healthcare provider before using any medication during pregnancy or breastfeeding. If applying to the nipples, wash the area thoroughly before breastfeeding.
Drug Profile Summary
- Mechanism of Action: Inhibits bacterial protein synthesis by binding to isoleucyl transfer-RNA synthetase.
- Side Effects: Common: local irritation (burning, stinging, itching); Rare: allergic reactions.
- Contraindications: Hypersensitivity to mupirocin.
- Drug Interactions: None known for topical application.
- Pregnancy & Breastfeeding: Generally considered safe for topical use.
- Dosage: Apply topically 2-3 times daily for up to 10 days.
- Monitoring Parameters: Monitor the infection site for improvement and any signs of adverse reactions.
Popular Combinations
Mupirocin is typically used as a monotherapy.
Precautions
- General Precautions: Avoid contact with eyes and mucous membranes. Discontinue use if severe irritation or sensitization occurs.
- Specific Populations: Use with caution in patients with severe renal impairment. For infants under 2 months, use only under the direction of a physician. If used on nipples during breastfeeding, wash the area thoroughly before nursing.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Mupirocin?
A: Adults and children 2 months and older: apply a small amount to the affected area 2-3 times daily for up to 10 days. For infants under 2 months, consult a physician.
Q2: What infections does Mupirocin treat?
A: Primarily impetigo, but also other bacterial skin infections like folliculitis, furunculosis, and secondarily infected wounds.
Q3: Can Mupirocin be used on the face?
A: Yes, but avoid contact with the eyes.
Q4: What are the common side effects of Mupirocin?
A: Burning, stinging, itching, and dryness at the application site are common.
Q5: Are there any drug interactions with Mupirocin?
A: No significant drug interactions are known for topical mupirocin.
Q6: Can Mupirocin be used during pregnancy or breastfeeding?
A: Generally considered safe due to minimal systemic absorption. Consult a healthcare professional before use.
Q7: How long does it take for Mupirocin to work?
A: Improvement should be seen within 3-5 days. Re-evaluate if no improvement is observed.
Q8: What should I do if I miss a dose of Mupirocin?
A: Apply the missed dose as soon as you remember, then continue with your regular schedule.
Q9: Can Mupirocin be used for all types of skin infections?
A: No. It’s primarily for bacterial skin infections. It is not effective against fungal or viral infections. It is not indicated for pressure sores.
Q10: What should I do if my skin gets irritated after using Mupirocin?
A: Discontinue use and consult your healthcare provider.
