GuidelinesEML (Adult Hospital STG)
Penicillin Desensitisation
Standard Treatment Guidelines and Essential Medicines List for South Africa, Hospital Level, Adults 2019 Edition
- This has been included for information only.
- Perform only in an ICU setting.
- Discontinue all ß-adrenergic antagonists. Have an IV line, ECG monitor and spirometer in place. Once desensitised, treatment must not lapse as risk of subsequent allergy increases.
- A history of Stevens-Johnson’s syndrome, exfoliative dermatitis, erythroderma are absolute contra-indications to desensitisation (use only as an approach to IgE sensitivity).
Oral route is preferred. 1/3 of patients develop a transient reaction during desensitisation or treatment, which is usually mild.
| A: Reconstitute phenoxymethylpenicillin 250 mg/ 5mL | ||
| Step | Medicine mg/mL | Amount to administer (mL) |
| Strictly every 15 minutes | B: To make 0.5 mg/mL solution: Dilute 0.5 mL of reconstituted phenoxymethylpenicillin solution in 49.5 mL water. | |
| 1 | 0.5 mg/mL solution (1000 units/mL) | 0.1ml |
| 2 | 0.2ml | |
| 3 | 0.4ml | |
| 4 | 0.8ml | |
| 5 | 1.6ml | |
| 6 | 3.2ml | |
| 7 | 6.4ml | |
| C: To make 05mg/mL solution: Dilute 1 mL of reconstituted phenoxymethylpenicillin solution in 9 mL water. | ||
| 8 | 5mg/mL solution (10000 units/mL) | 1.2ml |
| 9 | 2.4ml | |
| 10 | 4.8ml | |
| D: Reconstituted phenoxymethylpenicillin 250mg/5mL = 50mg/mL | ||
| 11 | 50mg/mL (80000units/mL) | 1.0mL |
| 12 | 2.0mL | |
| 13 | 4.0mL | |
| 14 | 8.0mL | |
After step 14, observe for 30 minutes, then give 1.0 g IV.
Interval between doses: 15 minutes.
Parenteral route
| Step | Medicine mg/mL | Amount to administer (mL) |
| Strictly every 15 minutes: | ||
| 1 | 0.1 mg/mL | 0.1 mL |
| 2 | 0.2 mL | |
| 3 | 0.4 mL | |
| 4 | 0.8 mL | |
| 5 | 1 mg/mL | 0.16 mL |
| 6 | 0.32 mL | |
| 7 | 0.64 mL | |
| 8 | 10 mg/mL | 0.12 mL |
| 9 | 0.24 mL | |
| 10 | 0.48 mL | |
| 11 | 100 mg/mL | 0.1 mL |
| 12 | 0.2 mL | |
| 13 | 0.4 mL | |
| 14 | 0.8 mL | |
| 15 | 0.16 mL | |
| 16 | 0.32 mL | |
| 17 | 0.64 mL | |
After step 17, observe for 30 minutes, then give 1.0 g IV.
Interval between doses: 15 minutes.
Standard Treatment Guidelines and Essential Medicines List for South Africa, Hospital Level, Adults 2019 Edition