Eur J Pediatr (1989) 149 : 136-137 EuropeanJournal of Pediatrics 9 Springer-Verlag 1989 Dosage of nifedipine in hypertensive crises of infants and children J. Lopez-Herce, P. Dorao, P. de la Oliva, M. A. Delgado, M. C. Martinez, and F. Ruza Paediatric Intensive Care Unit, Children's Hospital "La Paz", Madrid, Spain Abstract. Eight hypertensive crises (HC) were treated with 2.5 mg of sublingual nifedipine in three children with weights below 10 kg (group A); 16 HC in 6 children between 10 and 20kg with 5 mg (group B); and 40 HC in 10 children over 20 kg with 10 mg of nifedipine (group C). The relative de- crease in both systolic and diastolic blood pressure was similar in all groups. The decrease was more rapid in groups A and B when the contents were extracted from the capsule and given directly. The hypotensive effect lasted 4 h. There were no side effects. The effective and safe singIe dose of nifedipine has been established to be 2.5 mg for children weighing less than 10 kg, and 5 mg for children weighing between 10 and 20 kg. Key words: Hypertensive crises - Nifedipine Introduction Sublingual nifedipine has proven to be a safe and effective drug for the treatment of hypertensive crises (HC) in adults [2, 3]. It is considered to be the drug of first choice in hyper- tensive emergencies on account of easy administration, fast action, the effect on blood pressure that is directly related top- retreatment levels and minor side effects [7]. Some reports have stated the effectiveness of 10 nag of sub- lingual nifedipine in paediatric patients weighing more than 20 kg [1, 4, 5, 8]. There is little experience in treating HCin smaller children. We have previously suggested a dosage of 5 mg for children with weights between 10 and 20 kg and 2.5 mg for children weighing less than 10 kg [4, 5]. We report our results with these dosages. Patients and methods Eight HC in three children weighing less than 10 kg were treated with 2.5 mg of sublingual nifedipine (Adalat, Bayer, FRG); 16 HC in 6 children weighing between 10 and 20 kg were managed with 5 mg of sublingual nifedipine. Age, sex, weights and diagnosis are presented in Table 1. 9 ~ 9 Offprint requests to: J. Lopez-Herce, Puentecesures 1B-1 B, E-2802 Madrid, Spain Abbrevialions: HC = hypertensive crises; mDBP = mean diastolic blood pressure; mSBP = mean systolic blood pressure The results obtained were compared to those in 40 HC in children weighing more than 20 kg, treated with 10 mg of sub- lingual nifedipine. Blood pressure was monitored either by an intra-arterial line or by oscillometric technique (Dinamap, Criticon) and registered 5, 10, 15, 30, 60,120,180 and 240 rain after medication. Statistical analysis was done as described previously [6]. Statistical significance was determined by two two-way analy- ses of variance with repeated measures of systolic blood pres- sure (SBP) and diastolic blood pressure (DBP) over time in the three groups. When the F ratio was statistically significant (P < 0.05) a multiple comparison test was used to determine the difference in population means. Results Mean initial SBP was 144.5 mmHg in group A, 152 mmHg in group B and 163 mmHg in group C. Mean initial DBP was 103 mmHg in group A, 106 mmHg in group B, and 113 mmHg in group C. The evolution and percentage decrease in mSBP and mDBP are shown in Fig. 1. mSBP and mDBP decreased 5 min after drug administra- tion in the three groups. This decrease was significantly higher in group A than in groups B and C at 5 and 10 rain (P < 0.01). The difference between groups B and C was not statistically significant 9 mSBP and mDBP decreased to a minimum at 30 min in groups A and B and at 60 min in group C. The maximal Table 1. Clinical data of patients of groups A and B Group Age Sex Weight Diagnosis Nifedipine A 3 months F 4 Congenital nephrotic 2.5 mg syndrome A 6 months F 8 Haemolytic-uraemic 2.5 mg syndrome A 7 months F 5.3 Interstitial pneumonia 2.5 mg B 1.5 years F 12 Myocardial tumour 5 mg B 2 years M 12 Chronic renal failure 5 mg B 2 years F 12 Intraeranial 5 mg haemorrhage B 3.5 years F 15 Haemolytic-uraemic 5 mg syndrome B 5 years M 17.5 Liver transplantation 5 mg B 6 years M 16.5 Guillain-Ban 9 5 mg syndrome