Description of the active substance:
This information is a reference and it is not enough that the drug has been prescribed by a doctor ..
PHARMACHOLOGIC EFFECT
Phosphodiesterase inhibitor, methylxanthine. Increases accumulation in the tissues of cAMP, blocks adenosine (purine) receptors; reduces the flow of calcium ions through the channels of cell membranes, reduces the contractile activity of smooth muscles. Relaxes the muscles of the bronchi, blood vessels (mainly the vessels of the brain, skin and kidneys); has a peripheral vasodilating effect, increases renal blood flow, has a moderate diuretic effect. Stabilizes the membrane of mast cells, inhibits the release of mediators of allergic reactions. Increases mucociliary clearance, stimulates contraction of the diaphragm, improves the function of the respiratory and intercostal muscles, stimulates the respiratory center. Normalizing the respiratory function, promotes the saturation of blood with oxygen and a decrease in the concentration of carbon dioxide; stimulates the centers of respiration. Strengthens lung ventilation in hypokalemia.
Has a stimulating effect on the activity of the heart, increases the strength of heartbeats and heart rate, increases coronary blood flow and the need for myocardium in oxygen. Reduces the tone of blood vessels (mainly vessels of the brain, skin and kidneys). Reduces pulmonary vascular resistance, lowers pressure in a small circle of blood circulation.
Increases renal blood flow, has a moderate diuretic effect. Expands extrahepatic biliary tract. It inhibits platelet aggregation (suppresses platelet activation factor and PgE 2? ), Increases the resistance of erythrocytes to deformation (improves rheological properties of blood), reduces thrombus formation and normalizes microcirculation.
PHARMACOKINETICS
When administered theophylline quickly and completely absorbed from the digestive tract. The presence of food in the stomach can affect the speed (but not the degree) of absorption of theophylline, as well as its clearance. When the dosage form is used, the usual duration of action of C max in plasma is reached in 1-2 hours.
After an / m injection, the absorption is slow and incomplete.
The binding to plasma proteins is approximately 40%; In newborns, as well as in adults with diseases, binding decreases.
Theophylline is metabolized in the liver with the participation of several cytochrome P450 isoenzymes, the most important of which is CYP1A2. In the process of metabolism, 1,3-dimethylurea, 1-methylmercury and 3-methylxanthine are formed. These metabolites are excreted in the urine. In unchanged form, adults are 10%. In newborns, a significant proportion is excreted in the form of caffeine (due to the immaturity of the ways of its further metabolism), in unchanged form - 50%.
Significant individual differences in hepatic metabolism rate of theophylline are the cause of pronounced variability in clearance values, plasma concentration, T 1/2 .The liver metabolism is affected by factors such as age, addiction to tobacco smoking, diet, diseases, concomitant drug therapy.
T 1/2 theophylline in non-smoking patients with bronchial asthma with practically no pathological changes from other organs and systems is 6-12 hours, in children 1-5 hours, in smokers 4-5 hours, in newborns and premature infants - 10 -45 h.
T 1/2 theophylline is increased in the elderly and in patients with heart failure or liver disease.
Clearance decreases with heart failure, violations of liver function, chronic alcoholism, pulmonary edema, with COPD.
INDICATIONS
Bronchoobstructive syndrome of different genesis: bronchial asthma (a drug of choice for physical stress asthma and as an additional remedy for other forms of bronchial asthma), COPD (chronic obstructive bronchitis, emphysema). Pulmonary hypertension, pulmonary heart, edematous syndrome of renal genesis (as part of combination therapy), nocturnal apnea.
DOSING MODE
Install individually. The initial dose is an average of 400 mg / day. With good tolerability, the dose can be increased approximately 25% from the initial every 2-3 days until the optimal therapeutic effect is achieved.
Maximum doses that can be used without monitoring the concentration of theophylline in the blood plasma: children aged 3-9 years - 24 mg / kg / day, 9-12 years - 20 mg / kg / day, 12-16 years - 18 mg / kg / day; patients aged 16 years and older - 13 mg / kg / day or 900 mg / day.
If the symptoms of toxic effects appear in the indicated doses or if there is a need for a further increase in the dose (due to an insufficient therapeutic effect), it is recommended to monitor the concentration of theophylline in the blood plasma. The optimal therapeutic concentrations of theophylline are 10-20 Ојg / ml. At lower concentrations, the therapeutic effect is weak, at large - there is no significant increase in therapeutic effect, while the risk of side effects increases significantly. The frequency of reception depends on the dosage form.
SIDE EFFECT
From the side of the central nervous system: dizziness, headache, insomnia, agitation, anxiety, irritability, tremor.
From the cardiovascular system: palpitation, tachycardia (including the fetus during admission in the III trimester), arrhythmias, a decrease in blood pressure, cardialgia, an increase in the frequency of angina attacks.
On the part of the digestive system: gastralgia, nausea, vomiting, gastroesophageal reflux, heartburn, peptic ulcer, diarrhea, with prolonged admission - a decrease in appetite.
Allergic reactions: skin rash, itching, fever.
Other: chest pain, tachypnea, sensation of hot flashes to the face, albuminuria, hematuria, hypoglycemia, increased diuresis, increased sweating. Side effects decrease with decreasing dose.
CONTRAINDICATIONS
Epilepsy, gastric ulcer and duodenal ulcer in the phase of exacerbation, gastritis with high acidity, recent bleeding from the gastrointestinal tract, severe arterial hyper- or hypotension, severe tachyarrhythmias, hemorrhagic stroke, retinal hemorrhage, children's age (up to 3 years, for prolonged oral forms - up to 12 years), hypersensitivity to theophylline and other xanthine derivatives (caffeine, pentoxifylline, theobromine).
PREGNANCY AND LACTATION
Theophylline penetrates through the placental barrier, excreted in breast milk.
In pregnancy, theophylline is used only if the intended benefit to the mother exceeds the possible risk to the fetus.
If it is necessary to use during lactation, it should be borne in mind that theophylline is excreted in breast milk.
APPLICATION FOR VIOLATIONS OF THE FUNCTION OF KIDNEYS
In severe liver disease, the dose of theophylline should be reduced.
APPLICATION FOR CHILDREN
Contraindicated in childhood (up to 3 years, for prolonged oral forms - up to 12 years).
APPLICATION IN ELDERLY PATIENTS
Use with caution in elderly patients.
SPECIAL INSTRUCTIONS
Use with caution in severe coronary insufficiency (acute phase of myocardial infarction, angina pectoris), widespread atherosclerosis of vessels, hypertrophic obstructive cardiomyopathy, ventricular extrasystole, chronic heart failure, increased convulsive readiness, with hepatic and / or renal insufficiency, peptic ulcer of stomach and duodenum in anamnesis), with uncontrolled hypothyroidism (the possibility of cumulation) or thyrotoxicosis, prolonged hyperthermia, gastroesophagealreflux, prostatic hypertrophy, pregnancy, lactation, in elderly patients, in children (especially for oral forms).
Use with caution rectally for diarrhea and rectal diseases.
The intensity of theophylline may decrease in smokers.
Theophylline is not used concomitantly with other xanthine derivatives.
In severe diseases of the cardiovascular system, liver, viral infections, as well as in elderly patients, the dose of theophylline should be reduced.
DRUG INTERACTION
With the simultaneous use of macrolides with antibiotics, allopurinol, cimetidine, oral contraceptives, isoprenaline, lincomycin, the clearance of theophylline decreases.
With the simultaneous use of beta-adrenoblockers, especially non-selective, can cause bronchoconstriction, which reduces the bronchodilating effect of theophylline.Possible decrease in the effectiveness of beta-blockers.
With the simultaneous use of stimulants? 2- adrenoreceptors, caffeine, furosemide, the effect of theophylline is enhanced.
When used simultaneously with aminoglutethimide, the effectiveness of theophylline may be reduced due to an increase in its excretion from the body.
With simultaneous use with acyclovir, an increase in the concentration of theophylline in the blood plasma and an increase in adverse reactions are possible.
With simultaneous use with verapamil, diltiazem, nifedipine, felodipine, the concentration of theophylline in the blood plasma is usually slightly or moderately altered in the absence of changes in bronchodilator action. The cases of increasing the concentration of theophylline in the blood plasma and enhancing its side effect in patients simultaneously receiving verapamil or nifedipine are described.
With the simultaneous use of disulfiram, the concentration of theophylline in the blood plasma increases and toxic reactions develop.
With the simultaneous use of lithium salts, it is possible to reduce their effectiveness.
With simultaneous use with propranolol, the clearance of theophylline decreases.
With simultaneous application with phenytoin, the concentrations of theophylline and phenytoin in the blood plasma decrease and their therapeutic effectiveness decreases.
With simultaneous use with phenobarbital, rifampicin, isoniazid, carbamazepine, sulfinpyrazone, the intensity of theophylline may decrease due to an increase in its clearance.
With simultaneous use with enoxacin or other fluoroquinolones, a significant increase in the concentration of theophylline in the blood plasma is possible.
