After oral administration of therapeutic doses, doxazosin is well absorbed, absorption (simultaneous reception of food slows the absorption of 1 hour). The maximum concentration in plasma is created in 3 hours. When evening reception time to maximum concentration is prolonged to 5 hours.
Bioavailability – 60-70% (first pass metabolism). Contact with blood proteins – about 98%. Excretion of plasma takes place in two phases, with a finite half-life 19-22 hours, allowing to take the drug once daily.
Doxazosin is side effects of tamoxifen extensively metabolized in the liver by demethylation of hydroxylation and,
in patients with impaired liver function, as well as the reception drugs that can alter hepatic metabolism, the process can break down the drug biotransformation. Main excretion through the intestine (65% as metabolites and about 5% of intact). The kidneys remove 10% studies with doxazosin in the elderly and in patients with kidney disease showed no significant pharmacokinetic differences.
Benign prostatic hyperplasia: for the treatment of difficulty or delay the outflow of urine associated with benign prostatic hyperplasia (BPH). The drug can be used in the presence of hypertension and with normal blood pressure. Hypertension is used in combination with other antihypertensive agents such as thiazide diuretics, beta-blockers, blockers “slow” calcium channel blockers or angiotensin-converting enzyme inhibitors.
- Increased sensitivity to doxazosin, other quinazoline derivatives or any of the components of the drug support.
- age of 18 years (effectiveness and safety have been established).
Precautions: in patients with side effects of tamoxifen hepatic impairment, aortic and mitral stenosis, orthostatic hypotension.
In the absence of adequate and well-controlled studies in pregnant Tonokardina safe use during pregnancy has not been established. Tonokardin should be used in these groups of patients only where, in the opinion of the physician, the potential benefits outweigh the potential risk to the fetus and / or child
Dosing and Administration
Doxazosin should be 1 time per day (morning or evening), regardless of the meal, not chewing and drinking plenty of water. Benign prostatic hyperplasia initial dose is 1 mg per day, in order to minimize the possibility of orthostatic hypotension / or fainting. If necessary, depending on the performance and availability of urodynamicssymptoms increase the dose (1-2 week intervals) to 4.2 mg / day. The maximum permissible dose is 8 mg per day. The recommended maintenance dose – 2-4 mg / day.
Hypertension The initial dose is 1 mg per day at bedtime. After the first dose the patient should remain in bed for 6 – 8 hours. This is required in connection with the side effects of tamoxifen opportunity, “first dose phenomenon”, especially pronounced on the background of the previous diuretics. In case of insufficient therapeutic effect, the daily dose can be increased to 2 mg every 1-2 weeks. Subsequently, every 1-2 weeks the dose can be increased to 2 mg. The vast majority of patients, the optimal therapeutic effect is achieved at a dose of 8 mg per day. The maximum daily dose of 16 mg per day should not be exceeded. After reaching a stable dose of a therapeutic effect is usually reduced (average therapeutic dose for maintenance therapy is typically 2 – 4 mg daily). The drug Tonokardin take long. Duration of treatment is determined by the physician.
the most frequently observed in clinical trials, especially in the early treatment of orthostatic hypotension, which in rare cases may cause fainting. Common reactions: asthenia, fatigue, malaise: the part of the central nervous system and the peripheral system: headache, dizziness, drowsiness. Allergic reactions: skin rash, urticaria. from the digestive system: nausea. On the part of the cardiovascular system:peripheral edema, fainting. The respiratory system: . rhinitis and notes the following adverse reactions in patients with arterial hypertension (cause-and-effect relationship has not been established .): bradycardia, tachycardia, palpitations, chest pain, angina pectoris, myocardial infarction, cerebrovascular accident, arrhythmias.
Benign prostatic hyperplasia (BPH) in patients with side effects of tamoxifen found the same side effects as the patients with arterial hypertension, as well as: Common reactions: allergic reactions, skin rash, pruritus, urticaria, back pain, joint pain, muscle aches, muscle weakness, muscle cramps, feeling of heat ( “hot flushes”), an increase in body weight. On the part of the central nervous and peripheral system: hypoesthesia , priapism, paraesthesia, tremor, impotence, insomnia, irritability, anxiety, nervousness, depression, sleep disorders. Since the cardiovascular system: decrease in blood pressure, orthostatic hypotension. respiratory system: bronchospasm, cough, shortness of breath, nasal bleeding. from the endocrine: gynecomastia. from the digestive system: nausea, dry mouth, abdominal pain, constipation, diarrhea, dyspepsia, flatulence, loss of appetite, nausea, anorexia, cholestasis, jaundice, hepatitis, abnormal laboratory values of liver function . From the urogenital system: dysuria, hematuria, violation of urination, nocturia, polyuria, urinary incontinence On the part of hematopoiesis and hemostasis system: thrombocytopenia, thrombocytopenic purpura, leukopenia. With the skin: alopecia, purpura. From the senses: blurred vision , noise in ears.