pediatric Drug Dosage

[drsnehamaheshwari]

Sir William Osler once said, “the desire to take medicine is perhaps the greatest feature which distinguishes man from animals.”There exist clear cut indications for prophylactic antibiotic usage given by renowned medical bodies such as American Heart Association for endocarditis prophylaxis. Still, antibiotics are the most widely abused prescribed drugs on the basis of inappropriate indications, dosages and duration of use. Approximately half of all antibiotics used in hospitals are given to patients without signs or symptoms.The problem is compounded while prescribing for children.

Most of the time ‘random’ age related prescriptions are given based on dosages for adults. The use of inappropriate antimicrobial drugs may result in ineffective therapy or contribute to the development of undesirable antibiotic resistance in the causative pathogens in the community. Without specific knowledge about correct pediatric dosage based on body weight / surface area and other factors such as gestational and postnatal age in neonates, a clinician is liable to prescribe the drugs in inappropriate suboptimal or excess dose with undesirable consequences.

Drug	Adult Dose	Child Dose
Amoxicillin	250-500mg 3Times/day	20-40mg/Kg/day in 3 doses
Amoxicillin + Clavulanic acid (coamoxiclav)	250-500mg amoxicillin +125-250mg clavulanic acid 3 times a day	20-40mg/Kg/day of amoxicillin in 3 doses
Ciprofloxacin	250-500mg every 12 hrs	25mg/Kg/day divided in 2 doses (12 hrs each). To be avoided in children below 18 yrs
Cefixime	200mg 2 times a day for 7 -10 days	8mg/Kg/day in 2 divided doses
Cefadroxil	0.5-1g OD or Bid	30mg/Kg/ day in 2 doses
Erythromycin	250-500mg (stearate or estolate salts) or 400mg ethylsuccinate salt every 6 hrs	30 to 50 mg /Kg/ day in divided doses every 6hrs
Azithromycin	500mg OD	10mg/Kg/day in a single dose
Clarithromycin	250-500mg every 12 hrs	7.5mg/Kg twice daily (upto 500mg twice daily)
Doxycycline	200mg on day 1 (100mg every 12 hrs) then 100mg daily	(age 8 yrs or older) : 4.4 mg/Kg in 2 divided doses on day 1 than 2.2 mg/Kg/day
Tetracycline	250-500 mg every 6 hrs	(age 8yrs or older)25-50 mg/kg/day divided into 6hrly doses
Ofloxacin	200-400 BID	10-15 mg/kg/day divided in 2 doses (every 12 hrs), max. dose 800 mg per day
Metronidazole	250-750mg every 8 hrs, not to exceed 4g in 24 hrs	30-50 mg/Kg/day in 3 divided doses for 5-10 day
Ornidazole	500mg twice daily for 5 days	10mg/ Kg every 12 hrs
Paracetamol	0.5-1 gm every 4-6 hrs Maximum dose 4g/day	10-15mg/Kg/ doses every 4-6 hrs maximum 5 doses in 1 day
Nimesulide	100mg/dose every 12 hrs	5mg/Kg/day divided every 8-12 hrs
Diclofenac sodium	75-150 mg/day in 2-4 divided doses, max. dose – 150mg/day	2-3mg/Kg/day in 2-4 divided doses
Ibuprofen	400-600mg/dose every 6-8 hrs maximum dose 2400mg/day	5-10mg/Kg/dose every 6-8hrs max. dose 40 mg/kg daily
Mefenamic acid	500 mg TID	Analgesic dose- 10-25/mg/Kg/day (divided into 6 hrly doses) Antipyretic dose- 3mg/Kg/dose every 6hrs Precaution – avoid in children with seizures

 

 

        

[drsnehamaheshwari]

Nystatin

Use – Oral candidiasis

Neonate: 100,000 units to each side of mouth X QID

Infant: 200,000 units to each side of the mouth X QID

Children and Adults: 400,000-600,000 units to each side of the mouth X QID

Nystatin tablet (500,000) units dissolved in 5 ml glycerin provides 100,000 units/ml

 

Fluconazole

Neonate >14 days, infants and children

Oropharangeal or oesophageal candidiasis

Day 1: 6mg/kg (max200mg) PO/IV (OD)

Then 3mg /kg/day (max100mg) PO/IV (OD) X 14-21 days 

        

[drsnehamaheshwari]

Antibiotic dosing– Virtually all resistance occurs by transposable element gene transfer promoted by the use of antibiotics, particularly at low doses and for long duration. Antibiotics should be used aggressively and for as short a time as is compatible with patient’s remission of the disease. Many clinicians follow the pattern of continuing antibiotics for a minimum of 48 hours after disappearance of symptoms. That would mean reevaluating the patient 1-2 days after initiation of antibiotics.

The dosage and duration of the therapy depend upon the nature of the infection and the severity of the infection. A simple urinary tract infection in an adult female may only require 3 days of oral therapy, but deep seated infections like osteomyelitis or endocarditis will require prolonged parenteral therapy for six weeks or more.

Contraindications and special precautions: In patients with blood disorders, active CNS diseases, hypersensitivity, sever hepatic failure, pregnancy, lactation, neonates, active peptic ulcers, asthma etc, it is advisable to seek opinion from the concerned physician before prescribing these drugs.

Interesting fact – Fluorides, Ibuprofen, Iron Salts, Iodine drugs, tetracycline ingestion may discolor stools black Greenish grey or white/speckling is seen with many oral antibiotics.

 

        

[drsnehamaheshwari]

 Maternal drugs to be avoided or used with great caution during breastfeeding

Possible effect on infant

Aspirin: Avoid high dose as there is risk of bleeding, Reye’s syndrome

Estrogens: Gynaecomastia in male infants

Metronidazole: Suspend breast feeding for 12hrs after single dose as it is secreted in large amounts in breast milk.

Phenobarbitone(and Other Sedatives): Sedation

Tetracycline: Teeth pigmentation, enamel hypoplasia, cataract, skeletal growth retardation

Streptomycin: deafness Alcohol Congenital cardiac, CNS, limb anomalies, Developmental delay, attention deficit, autism

Vitamin D analogues (alfacalcidol, calcitriol): Aortic stenosis (supraclavicular), hypercalcemia (avoid high doses)

        

[drsnehamaheshwari]

Important Interactions between Antibiotics and other drugs

	Interacting drug	Effect
Ciprofloxacin (and most other quinolones)	Antacids, iron, sucralfate theophyline, cyclosporin, warfarin	Decrease absoption of quinolones Increase effect of theophyline, cyclosporine, warfarin
	NSAID	Increase risk of CNS stimulation seizures
Clindamycin	Erythromycin	Mutual antagonism
Erythromycin	Carbamazepine	Inceases serum levels of carbamazepine causes nystagmus, ataxia, vomitting, (avoid this combination)
Metronidazole	Anticoagulants	increases anticoagulant effect
	Phenobarbitones, hydantoins	Decreases effect of metronidazole
Tetracyclines	antacids, iron, sucralfate,digoxin	Decreases tetracycline effect Increases toxicity of digoxin (may persist for several months in 10% patients)

  

        

[drashwin]

Great! Your effort of sharing the drug dosages for pediatric patients is laudable. All practitioners should know the basisc of prescribing drugs to children; and that they need to be prescribed on the basis of the weight of children. It is mandatory to have a weighing scale in a clinic. Please find below a further simplified chart for easy calculations. Anyone, please feel free to contact me if any clarification is required.

(Disclaimer: I do not endorse any products; trade names* given below are only examples)

Drug	Trade Name*/ Formulation	Dosage	Weight	Dose	Frequency
Ibuprofen	Sy. Ibugesic 100mg Tab. Brufen 200 mg Tab. Brufen 400 mg	10mg/kg/dose	10kg 20kg 40kg	5ml 10ml/ 1 tab 200mg 1 tab 400mg	TID/QID; SOS
Paracetamol	Sy. Crocin 125mg Sy. Crocin DS 250mg Tab Crocin 500mg	15mg/kg/dose	8kg 16kg 32kg	5ml 5ml 1tab 500mg	TID/QID; SOS
Amoxycilin	Sy. Mox 125mg Sy. Mox 250mg Cap 500 mg	20-90mg/kg/day in divided doses	7.5kg 15kg 30kg	5ml 5ml 1 cap	TID
Amoxy + Clav	Sy. Augpen HS Sy. Augpen DS	30-90mg/kg/day in divided doses	10kg 20kg	5ml 5ml	BID (High/ Double Strength)
Metronidazole	Sy. Flagyl 200mg   Tab. Flagyl 400 mg	30mg/kg/day in divided doses	10kg 20kg 40 kg	2.5ml 5ml 1 tab 400 mg	TID

        

[drsnehamaheshwari]

 This makes prescribing pediatric drugs even more easy. An excellent guide for fresh graduates and clinicians.

        

[Author]

Posts