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Tazocin (Piperacillin / Tazobactam)

Overview

Field Detail
Drug class Beta-lactam / penicillin + beta-lactamase inhibitor
Stock vial 4 g / 500 mg powder for injection
Reconstituted conc. See Preparation (1:10 dilution — 20 mg / 2 mg per mL)
Storage Room temp before; 2–8°C after

Preparation

Before you start

Ensure the vial contains 4 g / 500 mg of Tazocin. Check expiry and integrity. Note that testing is performed at a 1:10 dilution of the initial reconstituted vial.

Equipment needed

  • 1 × Tazocin 4 g / 500 mg vial
  • Normal saline (NS) — for all dilutions
  • 20 mL syringe (for initial reconstitution)
  • 1 mL syringes × 4 (for test doses/dilutions)
  • 25 G needles

Step 1 — Initial Reconstitution (200 mg / 25 mg per mL)

  1. Add 20 mL NS to the 4.5 g (4 g/500 mg) vial.
  2. Dissolve completely to obtain Piperacillin 200 mg/mL and Tazobactam 25 mg/mL.
  3. Note: This solution is NOT for testing.

Step 2 — Prepare the SPT and IDT 1:10 (20 mg / 2 mg per mL)

  1. Draw up 0.1 mL of the initial (200/25 mg/mL) solution into a 1 mL syringe.
  2. Add 0.9 mL NS. Mix.
  3. Total concentration is Piperacillin 20 mg/mL and Tazobactam 2.5 mg/mL.
  4. Label: "Tazocin SPT/IDT 20/2 mg/mL".

Step 3 — Prepare IDT dilutions

Prepare in this order, using a fresh syringe for each step.

  1. IDT 2/0.2 mg/mL (1:100):
    • Draw 0.1 mL of the 20/2 mg/mL solution (from Step 2) into a new 1 mL syringe. Add 0.9 mL NS. Mix.
    • Label: "Tazocin IDT 2/0.2 mg/mL".

Skin prick test (SPT)

Reagent Concentration
Test solution 1:10 (20/2 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 2/0.2 mg/mL 0.1 mL of 20/2 mg/mL + 0.9 mL NS
2 1:10 20/2 mg/mL 0.1 mL of stock solution + 0.9 mL NS

Note: The dilution ratios are relative to the initial 200 mg/mL Piperacillin stock.

Inject: 0.05 mL intradermal. Read at 15–20 minutes.