Abstract
Dexamethasone (Dex) produces an unpredictable adrenal suppressive response in CAH patients. Maintenance steroid therapy was stopped for 48h in 11 patients (14-21 yr) with 21-OH deficiency. Each then received 0.01 mg/kg boluses of Dex I.V. and orally on consecutive days at 0900 h. Plasma 17P and Dex levels were measured every 10 min. for the first hour, then hourly for 24h on each occasion. Dex elimination half life (t½ β Dex) was 2.18 - 4.50h (mean 3.53). Mean plasma 17P pre-I.V.Dex (17P max) was 331 nmol/l (42-565); individual values were inversely proportional to adequacy of control on maintenance therapy. Both I.V. and oral Dex caused an immediate and exponential fall in 17P to produce complete cessation of adrenal 17P secretion followed by natural 1st order elimination of 17P from plasma, tip 17P was 1.93 - 2.93h (mean 2.55). Satisfactory 17P levels (< 30 nmol/l) were achieved up to 13.2h (mean 8.2) after a Dex dose. 17P levels were maintained for a period (P) ranging from 16-20h (mean 18h) until a sharp rise at light, t½ β Dex did not correlate with P; the former value (mean 3.53h) predicts <3% Dex dose remaining after 18h. A single norning dex dose (0.01 mg/kg) causes complete suppression of iaytime 17P values but when 17p increases again depends on 17Pmax at time of dose, t½ β 17P and 17P circadian rhythm periodicity; he last 2 parameters are unique to each patient.
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Shen, S., Young, M., Walker, R. et al. 17 PHARMACODYNAMIC RESPONSE OF 170H-PROGESTERONE (17P) TO ACUTE DEXAMETHASONE IN CONGENITAL ADRENAL HYPERPLASIA (CAH). Pediatr Res 24, 520 (1988). https://doi.org/10.1203/00006450-198810000-00038
Issue Date:
DOI: https://doi.org/10.1203/00006450-198810000-00038