How does smoking affect theophylline?
For example, the smoking cause increase of theophylline clearance by 58–100% and decrease its half life (T/2) by 63% in the smokers organism compared with nonsmokers. This is because it is highly metabolized by CYP1A2. Smoking cessation for 1 week reduces the elimination of theophylline by 35% .
How does smoking affect pharmacokinetics?
Therefore, smoking might potentially interfere with the pharmacokinetics of several drugs. Currently, it is known that smoking accelerates the metabolism of many different agents (i.e., clozapine, quinine, and propanolol).
How does smoking induce CYP1A2?
The induction of CYP1A2 is mediated by binding of polycyclic aromatic hydrocarbons of the tobacco smoke to the aryl hydrocarbon receptor (AHR) with consequent transcriptional activation of the CYP1A2 gene.
Is smoking an enzyme inducer?
Smoking is a potent inducer of CYP1A2 enzyme activity, resulting in significant lower clozapine serum concentrations in smokers compared with non-smokers, upon a given dose. Recently, a single nucleotide polymorphism identified at position 734 of the CYP1A2 gene, was reported to affect the inducibility of the enzyme.
Can you smoke on theophylline?
theophylline food It is best to avoid smoking and to limit caffeine consumption during theophylline therapy. Talk to a healthcare professional if you have any questions or concerns.
How does smoking affect aminophylline?
Stopping smoking Smokers taking theophylline generally tend to require higher doses than non-smokers as tobacco smoke contains polycyclic hydrocarbons, which induce CYP1A2. Smoking cessation will therefore result in an increase in serum theophylline concentrations, and possibly toxicity, if the dose is not reduced.
How does smoking affect ADME?
The pharmacodynamic interactions are mainly caused by the effects of nicotine, a cigarette smoke component. Through interactions, smoking could also modify the activity of transporter proteins, altering this way the ADME properties of many drugs.
Does smoking affect INR levels?
While there is a paucity of data to determine the clinical impact of smoking on warfarin, it is proposed that hydrocarbons in cigarette smoke induce CYP1A2, CYP1A1, and CYP2E1. The induction of these enzymes creates the potential for an increase in the concentration of warfarin, thus leading to an increase in INR.
Does smoking induce P450?
Cigarette smoking induces the activity of human cytochromes P450 (CYP) 1A2 and 2B6. These enzymes metabolise several clinically important drugs, including clozapine, olanzapine and methadone.
How does smoking affect heparin?
Cigarette smoking results in faster clearance of heparin, possibly related to smoking-related activation of thrombosis with enhanced heparin binding to antithrombin III. Cutaneous vasoconstriction by nicotine may slow the rate of insulin absorption after subcutaneous administration.
Can you smoke cigarettes while on Xarelto?
Smoking. Smoking cigarettes is not recommended for anyone, but it can be especially dangerous while taking blood thinners. When cigarette chemicals are absorbed into the liver, problems can occur. The liver is vital in making enzymes to eliminate toxins.
Is it OK to smoke cigarettes while on medication?
Tobacco smoke interacts with medications by influencing the absorption, distribution, metabolism, or elimination of other drugs, potentially causing an altered pharmacologic response. Because of these interactions, smokers may require higher doses of medications. Upon cessation, dose reductions might be needed.
How does cigarette smoke affect theophylline metabolism?
The cytochrome P450 enzyme CYP1A2 mediates the rate-limiting step in the metabolism of Theophylline 1, andthe polycyclic aromatic hydrocarbons found in cigarette smoke are potent inducers of this enzyme 2. For this reason, smokers may need up to double the dose of Theophylline to achieve therapeutic effect compared with non-smokers 3.
Why is theophylline metabolized by CYP1A2?
This is because it is highly metabolized by CYP1A2. One week after a patient quit smoking, theophylline’s clearance was decreased by 38% and its half-life was increased by 36%. After only 24-36 hours of smoking cessation, theophylline’s pharmacokinetics are not significantly changed.
Do smokers need more theophylline than non-smokers?
For this reason, smokers may need up to double the dose of Theophylline to achieve therapeutic effect compared with non-smokers 3. The relationship between smoking cessation and Theophylline has also been the subject of many studies.
What is the half life of theophylline in smokers?
The half-life of theophylline in smokers averaged 4.3 (SD = 1.4) hr, significantly shorter than the mean value in nonsmokers (7.0, SD = 1.7 hr). The apparent volume of distribution of theophylline was somewhat larger in smokers (0.50 ± 0.12 L/kg) than in nonsmokers (0.38 ± 0.04 Llkg).