Drug requirements:
(1) liquid oral suspension of trimethoprim-sulfamethoxazole with 40 mg TMP and 200 mg SMZ in 20 mL
(2) sterile diluent
(3) double strength TMP-SMZ tablets with 160 mg TMP and 800 mg SMZ
Preparation of serial dilutions of liquid suspension:
(1) Dilute the TMP-SMZ suspension with 5 mL diluted to 50 mL (1:10).
(2) Dilute 5 mL of 1:10 dilution to 50 mL (1:100).
(3) Dilute 5 mL of the 1:100 dilution to 50 mL (1: 1,000).
(4) Dilute 5 mL of the 1:1,000 dilution to 50 mL (1:10,000)
|
Dilution
|
TMP
|
SMZ
|
|
1:10
|
4 mg
|
20 mg
|
|
1:100
|
0.4 mg
|
2 mg
|
|
1:1,000
|
0.04 mg
|
0.2 mg
|
|
1:10,000
|
0.004 mg
|
0.02 mg
|
Protocol:
(1) The desensitization should be done under observation with emergency supplies immediately available.
(2) No corticosteroid or antihistamine therapy is given before therapy.
(3) Administer 5 mL (about 1 teaspoon) of the 1:10,000 dilution orally, followed by 6 ounces (about 190 mL) of water.
(4) In 1 hour administer 5 mL of the 1:1,000 dilution orally, followed by 6 ounces of water.
(5) In 1 hour (2 hours into protocol) administer 5 mL of the 1:100 dilution orally, followed by 6 ounces of water.
(6) In 1 hour (3 hours into protocol) administer 5 mL of the 1:10 dilution orally, followed by 6 ounces of water.
(7) In 1 hour (4 hours into protocol) administer 5 mL of the undiluted suspension orally, followed by 6 ounces of water.
(8) In 1 hour (5 hours into protocol) administer 1 double strength tablet (160 mg TMP, 800 mg SMZ) followed by 6 ounces of water.
If the patient developed macular rash, fever or nausea (mild reaction), then the patient treated with oral diphenhydramine (Benadryl) or ibuprofen.
If the patient develops urticaria, dyspnea, severe vomiting or hypotension (signs of possible anaphylactic reaction), then the desensitization is stopped immediately with appropriate management of allergic reactions.
