Doxazosin is a drug that has a hypotensive, lipid-lowering, vasodilator and antispasmodic action.
Release form and composition
The active component of Doxazosin is a substance of the same name.
Available drug in the form of tablets:
- Round flat at a dose of 1 mg;
- Capsule biconvex with a content of 2 mg of the active substance;
- Diamond biconvex at a dosage of 4 mg.
Auxiliary ingredients: sodium glycolate, sodium lauryl sulfate, magnesium stearate, starch, milk sugar, microcrystalline cellulose.
Indications for use
According to the instructions, Doxazosin is used to treat:
- Arterial hypertension (as a single agent or in combination with other antihypertensive drugs: ACE inhibitors, calcium channel blockers, beta-blockers, thiazide diuretics);
- Benign prostatic hyperplasia (both in the presence of arterial hypertension and in normal blood pressure).
The use of doxazosin, according to the instructions, is contraindicated in:
- Hypotension, accompanied by orthostatic disorders, including the presence of indications of such a state in history;
- Stones in the bladder;
- Lactase deficiency;
- Urinary tract infections;
- Lactose intolerance;
- Glucose-galactose malabsorption;
- Progressive or severe renal failure;
- Hypersensitivity to doxazosin, other quinazoline or any auxiliary component.
In addition, due to the lack of data on the safety and efficacy of doxazosin, the drug is not prescribed:
- Children under 18;
- Pregnant women;
- During the period of breastfeeding.
With extreme caution, the elderly should take the medication if it is necessary to have an operation for cataracts, as well as to patients if they have:
- Aortic and / or mitral stenosis;
- Impaired liver function;
- Hepatic failure;
- Disorders of cerebral circulation;
- Left ventricular failure with low filling pressure;
- Heart failure, characterized by increased cardiac output;
- Right ventricular failure due to embolism of the pulmonary artery or exudative pericarditis.
Dosing and Administration
According to the instructions, Doxazosin should be taken once a day, regardless of food, optimally - before bedtime, but it is possible in the morning.
The initial dose for any indication is 1 mg per day. The first pill should always be taken at bedtime, because after the first dose of the medicine you need to lie down for 6-8 hours, because there is a likelihood of the development of the “first dose” phenomenon, manifested by dizziness, hypotension, and sometimes syncopal states. Especially the risk increases in patients who took diuretics, and after taking Doxazosin are in a standing position.
In case of insufficiency of the therapeutic effect in the case of arterial hypertension, after 1-2 weeks of treatment, the dose of Doxazosin is increased to 2 mg. If this dosage is not enough, at intervals of 1-2 weeks it is increased further to 4-8-16 mg. The maximum permissible daily dose is 16 mg - it is prescribed in extreme cases. It is considered preferable to take 8 mg of doxazosin and the simultaneous use of another antihypertensive agent. After achieving a stable therapeutic effect, the dose is gradually reduced in the same way as it was increased. Maintenance therapy involves taking 2-4 mg per day.
If the initial dosage of 1 mg is not sufficient in the case of benign hyperplasia, it is gradually (once every 1-2 weeks) increased, taking into account the severity of symptoms of the disease and urodynamic indices. The recommended maintenance dose is 2-4 mg, in some cases it can reach 8 mg.
The duration of Doxazosin use is determined by the attending physician individually for each patient. Long-term drug treatment.
When using Doxazosin, the following side effects may occur:
- Headache, drowsiness, dizziness, asthenia, fatigue, nervousness, malaise;
- Rhinitis, nasal bleeding;
- Peripheral edema, fainting;
- Decreased blood pressure, orthostatic hypotension;
- Blurred vision, tinnitus;
- Cough, shortness of breath, bronchospasm;
- Constipation / diarrhea, nausea and / or vomiting, abdominal pain, flatulence, loss of appetite;
- Jaundice, hepatitis, increased liver enzymes, cholestasis;
- Insomnia, irritability, sensitivity disorders, dry mouth, tremor, paresthesia;
- Thrombocytopenia, leukopenia, thrombocytopenic purpura;
- Allergic reactions;
- Weight gain, alopecia, back pain, hot flashes.
In patients with benign prostatic hyperplasia, in addition to the described side effects, urinary disturbance, nocturia, urinary incontinence, hematuria, polyuria, priapism, gynecomastia are sometimes noted.
In addition, there is evidence of the occurrence of chest pain, rapid heartbeat, bradycardia, tachycardia, arrhythmias, cerebrovascular accident, angina, myocardial infarction. However, the causal relationship between the development of the described symptoms and the use of Doxazosin has not been reliably established.
Dizziness, blurred vision and drowsiness (including pathological) are possible side effects of Doxazosin with potentially dangerous consequences. This should be taken into account by people driving and engaged in industries that require attention, reaction speed and visual acuity.
Doxazosin analogs for the active substance are Doxaprostan, Artezin, Zokson, Kardura, Kamiren, Magurol, Urokard, Tonokardin.
Terms and conditions of storage
Doxazosin belongs to the group of prescription drugs. Store the tablets, according to the instructions, should be in a dry, dark place at temperatures up to 25 ºС. Their shelf life is 2 years.