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Ceftriaxone

Overview

Field Detail
Drug class 3rd generation cephalosporin
Stock vial 1 g powder for injection
Reconstituted conc. 100 mg/mL (add 10 mL WFI)
Storage Room temp before; 2–8°C after

Preparation

Before you start

Ensure the vial contains 1 g of Ceftriaxone. Check expiry and integrity.

Equipment needed

  • 1 × Ceftriaxone 1 g vial
  • Water for injection (WFI) — at least 10 mL
  • Normal saline (NS) — for IDT dilutions
  • 10 mL syringe (for reconstitution)
  • 1 mL syringes × 3 (for test doses)
  • 25 G needles

Step 1 — Reconstitution

  1. Reconstitute the 1 g vial with 10 mL WFI.
  2. Dissolve completely to obtain Ceftriaxone 100 mg/mL (Neat).

Step 2 — Prepare the SPT solution (100 mg/mL — neat)

  1. Draw up 0.5–1 mL of the neat (100 mg/mL) solution into a 1 mL syringe.
  2. Label: "Ceftriaxone SPT 100 mg/mL".

Step 3 — Prepare IDT dilutions

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

  1. IDT 10 mg/mL (1:10): Draw 0.1 mL of neat (100 mg/mL) into a 1 mL syringe. Add 0.9 mL NS. Mix. Label: "Ceftriaxone IDT 10 mg/mL".
  2. IDT 1 mg/mL (1:100): Draw 0.1 mL of the 10 mg/mL syringe into a new 1 mL syringe. Add 0.9 mL NS. Mix. Label: "Ceftriaxone IDT 1 mg/mL".

Skin prick test (SPT)

Reagent Concentration
Test solution Neat (100 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 1 mg/mL 0.1 mL of 10 mg/mL + 0.9 mL NS
2 1:10 10 mg/mL 0.1 mL neat + 0.9 mL NS

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