Seizures is a major toxicity of theophylline. The mechanism of theophylline-induced seizures is not known, but antagonism at adenosine receptors may be a possibility. The effect of pretreatment with different doses of adenosine (100, 500 and 1000 mg/kg, i.p.), and the adenosine A1 receptor agonist N6-cyclopentyladenosine (CPA), 1, 5 and 10 mg/kg, i.p., was studied against seizures induced by th...

In the driven isolated left atrium of the rabbit theophylline shortened relaxation time in a similar manner to isoprenaline and histamine. 2 Phenylephrine lengthened relaxation time in a similar manner to calcium. 3 Theophylline caused phenylephrine to shorten relaxation time, which was inhibited by a beta-adrenoceptor blocking drug, but theophylline did not potentiate the effect of phenylephri...

BACKGROUND While cytochrome P4501A2 is the primary pathway for theophylline (aminophylline ethylenediamine) metabolism in adults, it is developmentally immature in the newborn. OBJECTIVE To report the developmental differences in theophylline toxicokinetics of neonates. DESIGN Case series. Three premature neonates received inadvertent intravenous overdoses of theophylline for apnea of prema...

We demonstrated the effect of hypoalbuminemia on theophylline disposition in rats. The pharmacokinetic parameters in Sprague-Dawley rats (SDRs) were compared with those in spontaneously hyperlipidemic rats (HLRs), which had approximately one half the serum albumin concentration of the SDRs, after a single 10 mg/kg injection (iv) of theophylline. Theophylline clearance (CL) in the HLRs was incre...

Fifty hospitalized children with asthmatic bronchitis and bronchial asthma were treated with a continuous intravenous drip infusion of aminophylline. To investigate the pharmacokinetics of theophylline in the presence of pyrexia, patients were divided into two groups based on body temperature: a pyrexia group (> or = 38 degrees C) and a non-pyrexia group (< 38 degrees C). Theophylline clearance...

We have investigated the effect of theophylline on the kinetics of the catalytic subunit of protein kinase and related factors in lung tissue. The results show that the point of highest concentration of the C subunit of protein kinase which is active in casein phosphorylation is at 3h of incubation time, but in the presence of 100 Ilg/ InL and 10µg/mL theophylline, this is shifted to I.S an...

The effect of theophylline on colony stimulating factor production by the lung tissue was investigated. Addition of various concentrations of theophylline to the lung conditioned medium enhanced CSF production at 10 µg/ml and at higher concentrations showed an inhibitory effect. Determination of the phosphate content of the medium showed a decrease at 1-3 hours of incubation. Addition of A...

Chitosan with excellent biodegradable and biocompatible characteristics has received attention as an oral drug delivery vehicle for controlled-release formulations. In this study an enteric-coated capsule containing theophylline-chitosan beads based on 23 factorial designs was prepared as a colon drug delivery system. The theophylline-chitosan gel beads were formulated by adding the drug-contai...

Several quinolone antibacterial agents are known to inhibit the metabolism of theophylline, with the potential to cause adverse events due to raised theophylline concentrations during coadministration. A randomized crossover study was therefore conducted with 12 healthy male volunteers (ages, 23 to 34 years; body weight, 64 to 101 kg) to evaluate a possible interaction between rufloxacin and th...