What is the mechanism of action of Xanthines?
The main mechanism of action of xanthine is represented by the inhibition of phosphodiesterase, enzyme that breaks a phosphodiester bond. The pharmacological activity of xanthine is expressed in smooth muscle, heart muscle, central nervous system and kidney.
What are the effects of methylxanthines?
Methylxanthine has some well-documented acute adverse effects. Toxic levels can produce tachycardia, cardiac dysrhythmias, feeding intolerance, and seizures (infrequently), although these effects are seen less commonly with caffeine at the usual therapeutic doses. Mild diuresis is caused by all methylxanthines.
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% [8].
How do the xanthine alkaloids produce their pharmacological effects?
These are plant alkaloids and components of coffee, tea and chocolate. The major pharmacologic actions of the xanthines are inhibition of tissue phosphodiesterases which increases cellular cyclic AMP levels by inhibition of its breakdown and metabolism. The xanthines also are adenosine receptor antagonists.
Which of the following physiologic effects are produced by Xanthines?
Xanthines also produce numerous physiological effects including positive inotropic and chronotropic effects on the heart, decreased airway resistance in the lung, and respiratory stimulation.
What is the most serious adverse effect of methylxanthines?
Adverse Effects Generally, with serum concentrations that exceed 20 mcg/ml, severe effects include intractable vomiting, arrhythmias, irregular heartbeat (slow or fast), cardiac arrest, allergic skin reactions, or seizures.
What is the effect of methyl xanthines on heart?
Systemic administration of methylxanthines can profoundly affect hemodynamic parameters, such as blood pressure and heart rate. These hemodynamic changes result from direct effects on myocardial contractility and conduction, on vascular tone, and on the sympathoadrenal system.
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.
What happens when you smoke 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.
Is xanthine a diuretic?
Caffeine has long been considered practically useless, so far as its diuretic action in human beings is concerned, and the term “xanthine diuretic” is therefore restricted to theobromine and theophylline, both of which are frequently employed in combination with other substances.
Are there any side effects to taking xanthine?
Xanthines also stimulate muscle and cardiac cells and neurons. Xanthines can cause a mild diuresis. The xanthines have many minor side effects (anxiety, nervousness, tremor, headache, dizziness) but are largely well tolerated in the doses used to treat asthma and chronic bronchitis.
Are there any side effects to taking methylxanthine?
Methylxanthine has some well-documented acute adverse effects. Toxic levels can produce tachycardia, cardiac dysrhythmias, feeding intolerance, and seizures (infrequently), although these effects are seen less commonly with caffeine at the usual therapeutic doses. Mild diuresis is caused by all methylxanthines.
What are the major uses of xanthine derivatives?
The major use of xanthine derivatives are for relief of bronchospasm caused by asthma or chronic obstructive lung disease. The most widely used xanthine is theophylline. The xanthines also have other activities mediated by their effects on different tissue phosphodiesterases including inhibition of platelet function and arterial vasodilation.
Which is the most effective methylxanthine for COPD?
Methylxanthines are nonselective inhibitors of phosphodiesterase, and by this mechanism have a modest bronchodilator effect. 205,229,230 Theophylline is the most commonly used methylxanthine and, in stable COPD, its effect is greater than that of placebo but less than that of LABAs or LAMAs.