Prescription: Quinsy: Peritonsillar Abscess

Where are you
You are FY2 in Medicine.

Who the patient is
Tracy Yates, aged 6 years, has been diagnosed with peritonsillar abscess (quinsy). She was managed in the ER. There are no signs of dehydration. Patient cannot eat or drink. Weight of the child is 23 kg.

Other information
Consultant has advised the following medications:
Phenoxymethylpenicillin
Metronidazole
IV fluids maintenance. Available fluid bag volume 500 ml.

Special note
Patient is allergic to clarithromycin. Patient had itching.

What you must do
Write down the prescription for the above medications. Check dose with BNF. Calculate the fluid dose.

Shortcut:

  1. Antibiotic: BENZYLPENICILLIN SODIUM 575 mg IV 7 days QID
    Additional information: Review in 48 hours
  2. Antibiotic: METRONIDAZOLE 172 mg IV 7 days TDS
    Additional information: Review in 48 hours
  3. Child Fluid Prescription Chart: Write 3 times, Volume 500 ml, Infusion fluid 0.9% NaCl + 5% DEXTROSE, Additives 10 mmol KCL, Rate 63 ml/hr

Explanation:
In Quincy, route of administration will be IV Antibiotics instead of oral, irrespective of child’s eating and drinking status. Both Metronidazole and Benzylpenicillin.

  1. Benzylpenicillin Sodium 25 mg per kg IV every 6 hours for 7 days. (If weight is 23 kg then dose is 575mg)
  2. Metronidazole 7.5 mg per kg 8 hourly IV for 7 days. (If weight is 23 kg then dose is 172mg)

Ref : BNF/BNFC
So we can prescribe the IV Antibiotics for 7 days, but in additional information do write to review in 48 hours.

Main aspect is the correct choice of fluids in all children scenarios it’s almost always Normal Saline with 5 percent dextrose with additive 10mmol of potassium Chloride per 500 ml bag

Note: Giving oral medication, if it is clearly given that child can eat and not vomiting is also fine, but its upto you, your decision.

Alternative method for fluid calculation

Per Day (over 24 hours) Rate Per Hour
First 10kg 100 mL/kg/day 4 mL/kg hr
Next 10kg 50 mL/kg/day 2 mL/kg/br
≥ 20.1kg 20 mL/kg/day 1 mL/kg/br

Take total, divide by 24 to get rate per hour

For example:

Per Day (over 24 hours)
First 10kg 1 to 10 kg 10 x 100 mL/kg/day = 1000 mls
Next 10kg 11 to 20 kg 10 x 50 mL/kg/day = 500 mls
≥ 20.1kg Above 20 kg 3 x 20 mL/kg/day = 60 mls
Total =1560 mls / 24 hrs
= 65 mls / hr

Because we have only 500ml bag we’ll give 3 x 500 ml bag = 1500 mls

5 Likes

I’m sorry, I can’t find Quinsy or Tonsilitis anywhere in the BNF. How am I do come up with the alternative of Benzilpenicillin?

i think you ll save time by simply knowing that the drug of choice is Benzylpenicillin Sodium ,the stations never change for quinsy, same age, weight and fluids, it will quite unfair to change the values as you dont have a calculator.

2 Likes

I have checked in the BNF 85 and Bencilpenillin V does not have indication for quinsy, only meningitis IV indication. Does anyone know which alternative medication can we prescribe in a case like this (can not swallow, chlarithro allergy)?

Well, this is medicine, not just link following. The consultant advised a penicillin. Patient can’t swallow, so you will use a non-oral form of penicillin. That would be either IntraMuscular or IV. Since he is an inpatient, IV would be preferred rather than causing unnecessary pain.

But if you want to read in the BNF, read this passage: " Phenoxymethylpenicillin (Penicillin V) has a similar antibacterial spectrum to benzylpenicillin sodium, but is less active. It is gastric acid-stable, so is suitable for oral administration. It should not be used for serious infections because absorption can be unpredictable and plasma concentrations variable. It is indicated principally for respiratory-tract infections in children, for streptococcal tonsillitis, and for continuing treatment after one or more injections of benzylpenicillin sodium when clinical response has begun. It should not be used for meningococcal or gonococcal infections. Phenoxymethylpenicillin is used for prophylaxis against streptococcal infections following rheumatic fever and against pneumococcal infections following splenectomy or in sickle-cell disease."

2 Likes

You are probably checking the Adult rather than pediatric version.

1 Like

Hi there, could you please explain to me why metronidazole is 172 mg not 172.5 mg?