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
Selective blocker of postsynaptic? 1- adrenoreceptors. Blocking these receptors of resistive (arterial) vessels, causes their expansion, reduction in OPSS and lowering blood pressure. Reduces afterload on the heart. It also causes a decrease in the tone of the capacitive (venous) vessels, reduces preload on the heart. Unlike non-selective blockers? 1 - and? 2- adrenoreceptor does not cause severe tachycardia.
Terazosin has some lipid-lowering effect: against the background of its use, there is a decrease in the level of cholesterol, LDL and VLDL (the mechanism of occurrence of these effects is not clear). In addition, terazosin normalizes urination in patients with benign prostatic hypertrophy (adenoma), because, by blocking postsynaptic? 1- adrenoreceptors of smooth muscles of the triangle and neck of the bladder, the proximal part of the urethra and the prostate gland - reduces resistance to the current of urine.
PHARMACOKINETICS
After oral administration, it is quickly and completely absorbed from the intestine. Absorption is not dependent on food intake; bioavailability is more than 90%. C max is achieved after 1 h. Binding to plasma proteins is 90-94%. Metabolized in the liver with the formation of 4 metabolites, one of which (piperazine derivative of terazosin) has antihypertensive activity.
T 1/2 - 12 hours. It is excreted with bile (60%) and kidneys (40%, 10% of them in unchanged form). With hepatic failure, the clearance decreases.
INDICATIONS
Arterial hypertension, benign prostatic hyperplasia.
DOSING MODE
Treatment should start with a low dose of 1 mg, take it immediately before bed, after which the patient should be in bed for several hours. Increase in the dose is produced gradually once a week. The maintenance dose, depending on the indications and the effectiveness of treatment, is 1-10 mg 1 time / day.
The maximum daily dose is 20 mg.
SIDE EFFECT
From the side of the cardiovascular system: at the beginning of treatment, orthostatic hypotension is possible up to syncope (the phenomenon of the first dose - more often with combination therapy with diuretics or beta-blockers), palpitation; rarely - postural hypotension, tachycardia.
From the side of the central nervous system: possible dizziness, headache, asthenia, drowsiness.
From the side of the digestive system: nausea.
Other: nasal congestion, visual impairment, peripheral edema, weight gain; rarely - impotence, the phenomenon of hemodilution.
CONTRAINDICATIONS
Pregnancy, lactation (breastfeeding), children's age, hypersensitivity to terazosin, hypersensitivity to other alpha-adrenoblockers.
PREGNANCY AND LACTATION
Terazosin is contraindicated in pregnancy. If it is necessary to use during the lactation period, the question of stopping breastfeeding should be solved.
APPLICATION FOR CHILDREN
Contraindicated in childhood.
SPECIAL INSTRUCTIONS
Before the start of therapy for benign prostatic hyperplasia, a malignant neoplasm of the prostate gland should be excluded. When the drug is prescribed for patients with benign prostatic hyperplasia, BP should be monitored at the beginning of treatment and when the dose is changed during therapy.
DRUG INTERACTION
With simultaneous use with beta-blockers, calcium channel blockers, ACE inhibitors, there is a risk of developing severe arterial hypotension, especially after taking the first dose of terazosin.
The vasodilating effect of alpha-adrenoblockers and calcium channel blockers can be additive or synergistic. With the simultaneous use of terazosin and verapamil, the development of severe arterial hypotension is partly due to the pharmacokinetic interaction: an increase in C max and AUC of terazosin.
When used simultaneously with diuretics, dizziness may develop.
