Intravenous cephalosporin therapy may be required for a patient with a previous history of allergy to penicillin or cephalosporin. Ghosal and Taylor used a protocol for intravenous desensitization to ceftazidime in patients with cystic fibrosis. The authors are from Sheffield Children's Hospital in England.
Patient selection:
(1) Desensitization to ceftazidime is not a good idea in a patient with a previous history of serious allergic reaction (anaphylactic) to ceftazidime.
(2) Desensitization may be considered in a patient with a serious allergic reaction to penicillin or other cephalosporin if the need is great.
(3) A patient with a history of Stevens-Johnson Syndrome, erythroderma or toxic epidermal necrolysis to ceftazidime should not undergo desensitization.
(4) Desensitization can usually be done safely in a patient with a minor allergic or nonallergic drug reaction to a beta-lactam antibiotic.
(5) A patient with fulminant infection who requires immediate therapy may need to be stabilized before attempting the desensitization.
Location for desensitization: This should be done in a health care setting under observation.
Equipment required:
(1) resuscitation supplies readily available
(2) a very accurate infusion pump
Time required for protocol: 2 days, with infusions over a minimum of 4 hours (actual time may vary depending on interval between drug exposures)
Infusion Solutions |
Ceftazidime in mg |
Normal Saline (0.9%) |
Final Concentration |
---|---|---|---|
day 1 steps 1 to 8 |
50 |
500 |
0.1 mg/mL |
day 1 steps 9 to 14 |
500 |
500 |
1.0 mg/mL |
day 2 |
1,000 |
500 |
2.0 mg/mL |
Infusions at each step are performed over 15 minutes. The final step each day may take longer than 15 minutes to infuse.
Day 1 |
Solution |
Amount in mL over 15 minutes |
Dose in mg |
Cumulative Dose in mg |
---|---|---|---|---|
step 1 |
0.1 mg/mL |
0.25 mL |
0.025 |
0.025 |
step 2 |
0.1 mg/mL |
0.50 mL |
0.05 |
0.075 |
step 3 |
0.1 mg/mL |
1.0 mL |
0.1 |
0.175 |
step 4 |
0.1 mg/mL |
2.0 mL |
0.2 |
0.375 |
step 5 |
0.1 mg/mL |
4.0 mL |
0.4 |
0.775 |
step 6 |
0.1 mg/mL |
8.3 mL |
0.83 |
1.63 |
step 7 |
0.1 mg/mL |
16.6 mL |
1.66 |
3.3 |
step 8 |
0.1 mg/mL |
25 mL |
2.5 |
5.8 |
step 9 |
1.0 mg/mL |
6 mL |
6 |
11.8 |
step 10 |
1.0 mg/mL |
12 mL |
12 |
23.8 |
step 11 |
1.0 mg/mL |
25 mL |
25 |
48.8 |
step 12 |
1.0 mg/mL |
50 mL |
50 |
98.8 |
step 13 |
1.0 mg/mL |
100 mL |
100 |
198.8 |
step 14 |
1.0 mg/mL |
307 mL |
307 |
505.8 |
Day 2 |
Amount of 2 mg/mL Solution over 15 minutes |
Dose in mg |
Cumulative Dose in mg |
---|---|---|---|
step 1 |
0.25 mL |
0.5 |
0.5 |
step 2 |
0.5 mL |
1.0 |
1.5 |
step 3 |
1.0 mL |
2.0 |
3.5 |
step 4 |
2.0 mL |
4.0 |
7.5 |
step 5 |
4.0 mL |
8.0 |
15.5 |
step 6 |
8.3 mL |
16.5 |
32 |
step 7 |
16.66 mL |
32.3 |
64 |
step 8 |
25 mL |
50 |
114 |
step 9 |
50 mL |
100 |
214 |
step 10 |
100 mL |
200 |
414 |
step 11 |
293 mL |
586 |
1,000 |
where:
• The volumes for day 1 steps 9-14 and day 2 steps 1-11 is each about 500mL, so the prepared infusion solutions will be emptied if the protocol is completed.
If the patient tolerated the 2 day course, then the patient was administered a standard therapeutic dose as an infusion over 1 hour.
If the patient tolerated the standard therapeutic dose, then the person was started on the regular therapeutic regimen at full dose.
If signs of minor reactions appear then EITHER:
(1) switch to an alternative antibiotic, OR
(2) attempt to suppress reaction with diphenhydramine and antipyretics
If signs of serious reaction appear, then:
(1) discontinue antibiotic infusion and abort desensitization
(2) treat hypotension and anaphylactic reaction
(3) switch to an alternative antibiotic
Specialty: Infectious Diseases, Pharmacology, clinical
ICD-10: ,