Evaluation of three theophylline dosing equations for use in infants up to one year of age

Asthma

Asthma has been recognized as a disease since the earliest times. In the Corpus Hippocraticum, Hippocrates used the term “ασθμα” to indicate any form of breathing difficulty manifesting itself by panting. Aretaeus of Cappadocia, a well-known Greek physician (second century A.D.), is credited with providing the first detailed description of an asthma attack [13], and to Celsus it was a disease with wheezing and noisy, violent breathing. In the history of Rome, we find many members of the Julio-Claudian family affected with probable atopic respiratory disorders: Caesar Augustus suffered from bronchoconstriction, seasonal rhinitis as well as a highly pruritic skin disease. Claudius suffered from rhinoconjunctivitis and Britannicus was allergic to horse dander [529]. Maimonides (1136–1204) warned that to neglect treatment of asthma could prove fatal, whereas until the 19th century, European scholars defined it as “nervous asthma,” a term that was given to mean a defect of conductivity of the ninth pair of cranial nerves.

Reliability of salivary theophylline in monitoring the treatment for apnoea of prematurity

OBJECTIVE

To evaluate the reliability of salivary levels of theophylline in monitoring therapy of apnoea of prematurity.

STUDY DESIGN

Aminophylline was administered intravenously in 13 infants with apnoea, in a loading dose of 5 mg/kg and maintenance dose of 3 mg/kg, every 8 h. The patients were divided into two groups according to their postconceptional age (PCA): group A, of infants with small PCA (32.8+/-2.0 weeks; n=6 cases), and group B, infants with higher PCA (37.1+/-0.8 weeks; n=7 cases).

RESULTS

A total of 57 paired samples of serum and saliva were obtained in all 13 infants. The mean serum level of theophylline was 7.8+/-5.8 microg/ml and the ratio between serum and salivary concentration of theophylline was 1.53+/-0.28. A strong correlation between the serum and salivary concentration of theophylline (r=0.973) was found. Infants with small PCA had significant higher serum concentration of theophylline than those with higher PCA (10.6 vs 5.3 microg/ml; P=0.0002). The difference between the mean ratios of serum/salivary theophylline levels in the two groups was low (1.44 vs 1.62; P=0.0155).

CONCLUSION

The strong correlation of theophylline in serum and in saliva recommends the salivary levels as a reliable method for monitoring the treatment of apnoea of prematurity.

Treatment of apnea of prematurity

In the last decade, knowledge regarding the neurodevelopment and functional aspects of the respiratory centers during postnatal maturation has increased substantially. However, an increase in such knowledge has not provided a basis for change in practice. The diagnosis of apnea of prematurity (AOP) is one of exclusion. All causes of secondary apnea must be ruled out before initiating treatment for AOP. Treatment will depend on the etiology as well as effectiveness and tolerability of the treatment by the patient. The primary goal of any treatment of AOP is to prevent the frequency of apnea lasting >20 seconds, and/or those that are shorter, but associated with cyanosis and bradycardia. The clinical management of AOP is not much different today than it was two decades ago, with pharmacologic and nonpharmacologic treatment options remaining the mainstay of therapy. Methylxanthines are still the most widely used pharmacologic agents. Due to the wider therapeutic index of caffeine and ease of once daily administration, it should be the preferred agent. Doxapram, or nonpharmacologic treatment measures such as nasal continuous positive airway pressure, may be considered in infants who are unresponsive to methylxanthine treatment alone. Treatment should be continued until there is complete resolution of apnea, and for some time thereafter. The choice of method for weaning treatment remains one of individual physician preference. Discharge from hospital after apnea requires close monitoring and some infants will require home apnea monitors. The decision to provide a home apnea monitor should be individualized for each patient, depending on the effectiveness of treatment and clinical response.