|
In 2013, WHO estimated that 42 million children under 5 years of age
were overweight, with 75% of them living in developing countries; and
the prevalence has increased from 4.2% in 1990 to 6.7% in 2010 [1]. More
obese children are being encountered in clinical practice, including
those requiring chronic drug therapy. These patients are at risk for
iatrogenic drug dose related complications as dosages are based on body
weight. We report a case of early onset hypertension following systemic
steroid therapy in a 10- year-old obese child with rheumatic carditis.
A 10-year-old boy presented with fever, migratory
joint pain, headache and generalized severe myalgia for a week. On
examination, he had fever and signs suggestive of congestive cardiac
failure. Body mass index (BMI) was 23.63 (>97 th
percentile). ESR was elevated (90 mm/hr) with a positive CRP and ASLO.
Cardiac ultrasound showed rheumatic carditis with left ventricular
dysfunction. He was treated with oral prednisolone (60 mg/day as 2 mg/kg
crossed the adult maximum dose) [2]. He developed hypertension (BP >95th
centile) within 3 days which required intravenous furosemide for 3 days
followed by oral nifedipine. Steroids were stopped and aspirin started.
His blood pressure decreased progressively to the normal range within 14
days following which nifedipine was discontinued.
Adverse effects of prednisone usually, develops after
prolonged use of doses in excess of the normal physiological
requirement, often after a week of usage [3]. As our patient presented
with early-onset drug-induced hypertension, it probably was iatrogenic
due to inappropriate dosage. A thorough literature search revealed the
lack of evidence for ideal drug dosing in obese children and no
stipulated guidelines [4,5].
Excess body weight alters the pharmacokinetics in
overweight and obese children leading to higher risk of toxicity or
reduced therapeutic efficacy [4]. There is limited data about the
pharmacokinetics and drug dosing in obese children as compared to
adults. All children with weight above adult maximum dosage would
receive the same dose of drug which, logically cannot be right (For
example, three 10-year-olds weighing 35 kg, 45 kg and 55 kg
respectively, would receive same adult maximum dosage). The
pharmacokinetics of adult maximum doses will certainly vary based on the
weight, and can lead to both toxicity and sub-therapeutic doses.
In view of continuing childhood obesity epidemic,
there is a need for further research regarding drug dosages in these
children. In spite of limited evidence, it is essential to have a
practice guideline on drug dosages for obese children.
References
1. World Health Organization. Childhood Overweight
and Obesity, 2013. Available From: http://www.who.int/
dietphysicalactivity/childhood/en. Accessed July 12, 2015.
2. Kumar RK, Tandon R. Rheumatic fever and rheumatic
heart disease: The last 50 years. Indian J Med Res. 2013;137:643-58.
3. Liu D, Ahmet A, Ward L, Krishnamoorthy P,
Mandelcorn ED, Leigh R, et al. A practical guide to the
monitoring and management of the complications of systemic
corticosteroid therapy. Allergy Asthma Clin Immunol. 2013;9:30.
4. Kendrick JG, Carr RR, Ensom MH. Pediatric obesity:
Pharmacokinetics and implications for drug dosing. Clin Ther.
2015;37:1897-923.
5. Mulla H, Johnson TN. Dosing dilemmas in obese children.
Arch Dis Child Educ Pract Ed. 2010;95:112-7.
|
