Usage
Dicloxacillin is a penicillinase-resistant penicillin antibiotic used to treat infections caused by bacteria, specifically penicillinase-producing Staphylococcus aureus. It is effective against infections like skin and soft tissue infections (e.g. cellulitis, impetigo), bone infections (osteomyelitis), respiratory tract infections, and endocarditis. It is not effective against viral infections.
Alternate Names
Dicloxacillin is the generic name. Brand names include Dynapen and Dycill.
How It Works
Pharmacodynamics: Dicloxacillin inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs). This leads to bacterial cell lysis and death. It specifically targets penicillinase-producing bacteria due to its resistance to breakdown by bacterial enzymes.
Pharmacokinetics:
- Absorption: Dicloxacillin is well-absorbed orally, but its bioavailability is reduced when taken with food. Therefore, it is best administered on an empty stomach (1-2 hours before or after meals).
- Distribution: Dicloxacillin is distributed widely throughout the body.
- Metabolism: Dicloxacillin undergoes minimal metabolism.
- Elimination: It is primarily excreted unchanged by the kidneys. Dosage adjustments may be needed in patients with renal impairment.
Dosage
Standard Dosage
Adults:
- Mild to Moderate Infections: 125-250 mg orally every 6 hours.
- Severe Infections: 250-500 mg orally every 6 hours.
Children (less than 40 kg):
- Mild to Moderate Infections: 12.5 mg/kg/day orally, divided every 6 hours.
- Severe Infections: 25 mg/kg/day orally, divided every 6 hours.
- Children (greater than 40 kg): Same as adult dose.
Special Cases:
- Elderly Patients: Monitor renal function; dosage adjustments might be needed for severe renal impairment.
- Patients with Renal Impairment: Reduce dosage or increase the dosing interval in severe impairment.
- Patients with Hepatic Dysfunction: Caution is advised, although specific guidelines are not available.
- Patients with Comorbid Conditions: Close monitoring is recommended.
Clinical Use Cases
Dicloxacillin is generally administered orally. Its use in settings like intubation, surgical procedures, mechanical ventilation, ICU, and emergency situations usually involves other antibiotic choices due to the severity of the infection and the need for intravenous administration. However, following initial IV therapy, dicloxacillin can be used for oral step-down therapy.
Dosage Adjustments
Dose adjustments may be necessary in cases of renal impairment. No specific adjustments are recommended for hepatic dysfunction, although caution is advised.
Side Effects
Common Side Effects:
Nausea, vomiting, diarrhea, abdominal pain, rash, itching, and urticaria.
Rare but Serious Side Effects:
Allergic reactions (anaphylaxis, angioedema), Clostridium difficile associated diarrhea (pseudomembranous colitis), interstitial nephritis, neutropenia, leukopenia, and thrombocytopenia.
Long-Term Effects:
With prolonged use, superinfections (e.g., fungal infections) may occur.
Adverse Drug Reactions (ADR):
Severe allergic reactions (anaphylaxis) require immediate intervention.
Contraindications
Hypersensitivity to dicloxacillin or other penicillins.
Drug Interactions
- Probenecid: Can increase dicloxacillin levels.
- Warfarin: Dicloxacillin may increase the risk of bleeding.
- Oral contraceptives: Effectiveness may be reduced.
- Tetracyclines: May interfere with the bactericidal effect of dicloxacillin.
Pregnancy and Breastfeeding
Dicloxacillin is considered generally safe during pregnancy (Pregnancy Category B). It is excreted in breast milk, so caution is advised during breastfeeding.
Drug Profile Summary
- Mechanism of Action: Inhibits bacterial cell wall synthesis.
- Side Effects: Nausea, vomiting, diarrhea, rash, allergic reactions.
- Contraindications: Hypersensitivity to penicillin.
- Drug Interactions: Probenecid, warfarin, oral contraceptives, tetracyclines.
- Pregnancy & Breastfeeding: Generally safe in pregnancy; caution advised in breastfeeding.
- Dosage: See detailed section above.
- Monitoring Parameters: Renal function tests, signs of allergic reaction, superinfection.
Popular Combinations
Dicloxacillin is not typically used in combination with other antibiotics.
Precautions
- General Precautions: Assess for penicillin allergy.
- Specific Populations: Monitor renal function in elderly and those with renal impairment.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Dicloxacillin?
A: Refer to the detailed dosage section above.
Q2: What infections is Dicloxacillin used for?
A: Primarily skin and soft tissue infections, bone infections, respiratory tract infections caused by penicillinase-producing Staphylococcus aureus.
Q3: How should Dicloxacillin be administered?
A: Orally, on an empty stomach (1-2 hours before or after meals) with a full glass of water.
Q4: What are the common side effects of Dicloxacillin?
A: Nausea, vomiting, diarrhea, rash, and allergic reactions.
Q5: Is Dicloxacillin safe during pregnancy?
A: It’s generally considered safe (Pregnancy Category B), but consult with an obstetrician.
Q6: Can Dicloxacillin be used in patients with renal impairment?
A: Yes, but dosage adjustment may be necessary. Monitor renal function.
Q7: What should I do if a dose is missed?
A: Take the missed dose as soon as possible, unless it is close to the next dose. Do not double the dose.
Q8: How long should treatment with Dicloxacillin continue?
A: It depends on the type and severity of the infection. Complete the full course prescribed, even if symptoms improve.
Q9: What are the signs of a serious allergic reaction to Dicloxacillin?
A: Difficulty breathing, swelling of the face or throat, hives, severe itching, rapid pulse, and dizziness. Seek immediate medical attention if these occur.
Q10: Can Dicloxacillin be crushed or chewed?
A: No, swallow the capsule whole.
