Theophylline adverse effects

Herbs that may T risk of theophylline adverse effects ... 

Prompted by a case of increased theophylline adverse effects in a patient given aciclovir, a study was carried out in 5 healthy subjects who were given single 320-mg doses of theophylline (as 400 mg of aminophylline) before and with the sixth dose of aciclovir 800 mg five times daily for 2 days. The AUC of the theophylline was increased by 45% and its total body clearance was reduced by 30% by the aciclovir. ... 

Evidence appears to be limited to a single case report and the studies in healthy subjects. The interaction only appears to be of moderate importance. Nevertheless, it would seem prudent to check for any signs of theophylline adverse effects (headache, nausea, tremor) during concurrent use, particularly in situations where the metabolism of the theophylline may already be reduced (other drugs or diseases), or where high doses of allopurinol are used. For mention that allopurinol may invalidate the results of phenotyping tests using caffeine, see Caffeine + Allopurinol ,... 

Patients receiving these agents may notice improvement in 1 to 2 weeks, but maximal benefit may not be seen for 4 to 6 weeks. Cromolyn and nedocromil appear to be similar in efficacy to the leukotriene antagonists and theophylline for persistent asthma.18 Both agents are well tolerated with adverse effects limited to cough and wheezing. Bad taste and headache have also been reported with nedocromil. One dose of cromolyn or nedocromil prior to exercise or allergen exposure will provide effective prophylaxis for 1 to 2 hours. Cromolyn and nedocromil are not as effective as albuterol for prophylaxis of exercise-induced asthma. 

Target serum theophylline concentrations are 5 to 15 mg/L (28 to 83 fimol/L). Adverse effects generally are not problematic at serum concentrations below 15 mg/L (83 ftmol/L), but the increased risk of adverse effects outweighs the increase in bronchodilation in most patients above 15 mg/L (83 fimol/L).36 Headache, nausea, vomiting, and irritability may occur at serum concentrations less than 20 mg/L (110 fimol/L) but are rare when the dose is started low and increased slowly. More serious adverse effects, including cardiac arrhythmias, seizures, toxic encephalopathy, and death can occur at higher concentrations.18 Arrhythmias and seizures may occur without nausea and vomiting, particularly in chronic toxicity. 

Theophylline is a non-specific phosphodiesterase inhibitor that increases intracellular cAMP within airway smooth muscle resulting in bronchodilation. It has a modest bronchodila-tor effect in patients with COPD, and its use is limited due to a narrow therapeutic index, multiple drug interactions, and adverse effects. Theophylline should be reserved for patients who cannot use inhaled medications or who remain symptomatic despite appropriate use of inhaled bronchodilators. 

Albuterol is the preferred bronchodilator for treatment of acute exacerbations because of its rapid onset of action. Ipratropium can be added to allow for lower doses of albuterol, thus reducing dose-dependent adverse effects such as tachycardia and tremor. Delivery can be through metered-dose inhaler (MDI) and spacer or nebulizer. The nebulizer route is preferred in patients with severe dyspnea and/or cough that would limit delivery of medication through an MDI with spacer. If response is inadequate, theophylline can be considered however, clinical evidence supporting its use is lacking. 

Theophylline is used pharmacologically to manage asthma. Therapeutic effect is seen at concentrations in plasma above 10 mg/L. At 20 mg/ L, adverse effects limit the usefulness of theophylline. 

Adverse reactions to drugs differ in both type and incidence in the pediatric population. Because of immature metabolic pathways, infants and children may have different metabolic patterns than adults. This at least partially explains why neonates require lower theophylline serum concentrations for the treatment of neonatal apnea and why the incidence of hepatotoxi-city following acetaminophen overdose is much lower in young children than in adults [44,45]. Antibiotic adverse effects unique to the pediatric population may... 

The H2RAs are generally well tolerated. The most common adverse effects are headache, somnolence, fatigue, dizziness, and either constipation or diarrhea. Cimetidine may inhibit the metabolism of theophylline, warfarin, phenytoin, nifedipine, and propranolol, among other drugs. 

In summary, the adverse effects associated with the quinolones appear presently to be mild to moderate in severity and reversible upon discontinuation of therapy. Severe systemic adverse reactions are rare [62], It is suggested that the use of these agents should be avoided, as far as possible, in children and pregnant women and that caution be used in their administration to patients with a seizure disorder or those taking theophylline or warfarin [62]. Articles suggesting the appropriate clinical usage for these important antibacterials have appeared [64],... 

Theophylline is a drug v/ith a narrov/ therapeutic index, plasma concentrations of v/hich must be maintained at 10-20 mg/L. Plasma concentrations above 20 mg/L increase the severity and frequency of adverse effects. 

This xanthine derivative is an only a modest bron-chodilator in COPD, and because of its narrow therapeutic range, frequently seen adverse effect and drug interactions, it is becoming less frequently used, some patients experience side effects even within the therapeutic range. The non-bronchodilator effects of theophylline such as systemic and pulmonary vascular dilatation, central nervous system stimulation, improvement of the strength and effectiveness of respiratory muscles and possibly anti-inflammatory effects are of disputed clinical significance at usual therapeutic levels. 

Geriatric Considerations - Summary Increased risk of side effects in patients with CVD and hepatic dysfunction. Theophylline has a narrow therapeutic index and is associated with numerous drug interactions. Target serum concentrations are 5-20 mg/L, with adverse effects increasing between 15-20 mg/L. Hepatic metabolism and renal excretion declines with age and the half-life of theophylline increases by 3 to 9 hours in older adults. Smoking induces theophylline metabolism therefore, if a pa-tienf sfops smoking, empiric dosage reduction may be indicated and follow serum concenfrafions closely. 

Theophylline improves long-term control of asthma when taken as the sole maintenance treatment or when added to inhaled corticosteroids. It is inexpensive, and it can be taken orally. Its use, however, also requires occasional measurement of plasma levels it often causes unpleasant minor side effects (especially insomnia) and accidental or intentional overdose can result in severe toxicity or death. For oral therapy with the prompt-release formulation, the typical dose is 3-4 mg/kg of theophylline every 6 hours. Changes in dosage result in a new steady-state concentration of theophylline in 1-2 days, so the dosage may be increased at intervals of 2-3 days until therapeutic plasma concentrations are achieved (10-20 mg/L) or until adverse effects develop. 

T effects OF amiodarone, astemizole, atorvastadn, barbiturates, bepridil, bupropion, cerivastatin, cisapride, clorazepate, clozapine, clarithromycin, desipramine, diazepam, encainide, ergot alkaloids, estazolam, flecainide, flurazepam, indinavir, ketoconazole, lovastatin, meperidine, midazolam, nelfinavir, phenytoin, pimozide, piroxicam, propafenone, propoxyphene, quinidine, rifabutin, saquinavir, sildenafil, simvastatin, SSRIs, TCAs, terfenadine, triazolam, troleandomycin, zolpidem X effects W/ barbiturates, carbamazepine, phenytoin, rifabutin, rifampin, St. John s wort, tobacco X effects OF didanosine, hypnotics, methadone, OCPs, sedatives, theophylline, warfarin EMS T Effects of amiodarone, diazepam, midazolam and BBs, may need X- doses concurrent use of Viagra-type drugs can lead to hypotension X- effects of warfarin concurrent EtOH use can T adverse effects T glucose ODs May cause an extension of adverse SEs symptomatic and supportive Rivasrigmine (Exelon) [Cholinesterase Inhibitor/Anri ... 

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