Levofloxacin¶
Overview¶
| Field | Detail |
|---|---|
| Drug class | Fluoroquinolone antibiotic |
| Stock formulation | 500 mg tablets or IV formulation |
| Reconstituted conc. | 5 mg/mL (Check with Pharmacy) |
| Storage | Room temp; Protect from light |
Preparation¶
Suspension Preparation
Levofloxacin for skin testing is typically prepared at 5 mg/mL. Consult the Manufacturing Pharmacist for the exact diluent and method if using tablets.
Equipment needed¶
- 1 × Levofloxacin 5 mg/mL solution
- Normal saline (NS) — for IDT dilutions
- 1 mL syringes × 2
- 25 G needles
Step 1 — Prepare the SPT solution (5 mg/mL — neat)¶
- Draw up 0.5–1 mL of the stock (5 mg/mL) into a 1 mL syringe.
- Label: "Levofloxacin SPT 5 mg/mL".
Step 2 — Prepare IDT dilutions¶
Prepare in this order, using a fresh syringe for each step.
- IDT 0.05 mg/mL (1:100):
- Draw 0.1 mL of stock (5 mg/mL) into a 1 mL syringe. Add 0.9 mL NS. Mix. (This is 0.5 mg/mL — 1:10).
- Draw 0.1 mL of this 0.5 mg/mL into a new 1 mL syringe. Add 0.9 mL NS. Mix. (This is 0.05 mg/mL — 1:100).
- Label: "Levofloxacin IDT 0.05 mg/mL".
Skin prick test (SPT)¶
| Reagent | Concentration |
|---|---|
| Test solution | Neat (5 mg/mL) |
| Positive control | Histamine 10 mg/mL |
| Negative control | Normal saline |
Interpretation: Wheal ≥3 mm vs negative control = positive.
Intradermal test (IDT)¶
Dilution series¶
| Step | Dilution | Concentration | Preparation |
|---|---|---|---|
| 1 | 1:100 | 0.05 mg/mL | 0.1 mL of 0.5 mg/mL + 0.9 mL NS |
Inject: 0.05 mL intradermal. Read at 15–20 minutes.