Paracetamol (Acetaminophen)¶
Overview¶
| Field | Detail |
|---|---|
| Drug class | Non-opioid analgesic / Antipyretic |
| Stock formulation | 1 g/100 mL IV (10 mg/mL) or 500 mg tablets |
| Reconstituted conc. | N/A (Ready to use) |
| Storage | Room temp |
Preparation (IV Testing)¶
Before you start
Check the IV formulation. Most bags are pre-mixed at 10 mg/mL. No dilutions are typically required for SPT.
Equipment needed¶
- 1 × Paracetamol 10 mg/mL IV bag/vial
- Normal saline (NS) — for IDT dilutions
- 1 mL syringes × 2
- 25 G needles
Step 1 — Prepare the SPT solution (10 mg/mL — neat)¶
- Draw up 0.5–1 mL of the stock (10 mg/mL) into a 1 mL syringe.
- Label: "Paracetamol SPT 10 mg/mL".
Step 2 — Prepare IDT dilutions¶
Prepare in this order, using a fresh syringe for each step.
- IDT 0.1 mg/mL (1:100):
- Draw 0.1 mL of stock (10 mg/mL) into a 1 mL syringe. Add 0.9 mL NS. Mix. (This is 1 mg/mL — 1:10).
- Draw 0.1 mL of this 1 mg/mL into a new 1 mL syringe. Add 0.9 mL NS. Mix. (This is 0.1 mg/mL — 1:100).
- Label: "Paracetamol IDT 0.1 mg/mL".
Skin prick test (SPT)¶
| Reagent | Concentration |
|---|---|
| Test solution | Neat (10 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 | 0.1 mg/mL | 0.1 mL of 1 mg/mL + 0.9 mL NS |
Inject: 0.05 mL intradermal. Read at 15–20 minutes. Delayed Reading: If history is suggestive of a delayed reaction, re-read at 24 and 48 hours.