(Doxazosin)
Doxar belongs to a group of medicines called alpha-adrenergic blockers. It works by relaxing blood vessels, reducing peripheral resistance, which leads to a decrease in blood pressure.
Doxar is also an antagonist of alpha1-adrenergic receptors in the prostate and bladder. It reduces symptoms associated with difficulty in urinating and improves urodynamic test results (related to urine flow).
Doxar is indicated for the treatment of:
Doxar is contraindicated in monotherapy in patients with urinary retention or anuria, with or without progressive renal failure.
Before starting treatment with Doxar, the patient should discuss it with their doctor or pharmacist.
At the beginning of treatment, orthostatic hypotension may occur, manifested by dizziness, weakness, rarely loss of consciousness (syncope). The doctor may recommend blood pressure monitoring at the beginning of treatment.
Patients with the following severe heart diseases should exercise caution when taking doxazosin:
In patients with known severe liver dysfunction, doxazosin administration is not recommended.
In patients taking PDE-5 inhibitors (e.g. sildenafil, tadalafil, vardenafil - drugs used for erectile dysfunction) as symptomatic hypotension may occur.
Prolonged, painful erections can occur very rarely. In such cases, the patient should immediately consult a doctor.
Use in patients undergoing cataract surgery
During cataract surgery in some patients taking or previously taking tamsulosin, "intraoperative floppy iris syndrome" (a variant of small pupil syndrome) has been observed. Before the procedure, the patient should inform the ophthalmologist about taking alpha-adrenergic blockers.
The patient should consult a doctor, even if the above warnings refer to situations that have occurred in the past.
Doxar is not recommended for use in children and adolescents under 18 years of age, as its safety and efficacy have not been established in this age group.
The patient should tell their doctor about all medicines they are taking or have recently taken, as well as any medicines they plan to take.
The patient should ask their doctor or pharmacist before taking Doxar if they are taking any of the following medicines, as they may affect the action of Doxar:
Doxar enhances the blood pressure lowering effect of other alpha-adrenergic blockers and antihypertensive medicines.
The blood pressure lowering effect of Doxar may be weakened by:
Caution is advised when using doxazosin with medicines that affect liver metabolism, e.g. cimetidine.
In vitro studies have not shown that doxazosin affects the binding of digoxin (a medicine used for heart failure and arrhythmias), warfarin (an anticoagulant), phenytoin (an antiepileptic and antiarrhythmic medicine) or indomethacin (a medicine used for rheumatoid arthritis) to plasma proteins.
In clinical trials, no interactions were found between Doxar and thiazide diuretics, furosemide (an antihypertensive and diuretic), beta-adrenergic blockers (medicines used for ischemic heart disease, arrhythmias, and hypertension), non-steroidal anti-inflammatory drugs (NSAIDs, e.g. ibuprofen), antibiotics, oral hypoglycemic agents (used for diabetes), uricosuric agents or anticoagulants. Doxazosin may increase plasma renin activity and urinary vanillylmandelic acid excretion. This should be taken into account when interpreting laboratory test results.
Doxar enhances the blood pressure lowering effect of other alpha-adrenergic blockers and other antihypertensive medicines.
Clinical trials have shown that doxazosin has a beneficial effect on lipids, significantly reducing total triglyceride, total cholesterol, and LDL fraction levels in plasma. Treatment with doxazosin has a beneficial effect on hypertension and lipid levels, resulting in a reduced risk of coronary artery disease.
Some patients taking alpha-adrenergic blockers for high blood pressure or prostate enlargement may experience dizziness or a feeling of emptiness in the head, which may be caused by a sudden drop in blood pressure when changing body position while sitting or standing. Some patients have experienced these symptoms when taking alpha-adrenergic blockers with medicines used for erectile dysfunction (impotence). To minimize the risk of these symptoms, it is recommended to take daily doses of alpha-adrenergic blockers regularly before starting treatment with medicines for erectile dysfunction.
The patient should tell their doctor or pharmacist about all medicines they are taking or have recently taken, as well as any medicines they plan to take.
If the patient is pregnant or breastfeeding, thinks they may be pregnant, or plans to have a child, they should consult their doctor or pharmacist before taking this medicine.
Hypertension treatment
The medicine may be used during pregnancy only if the doctor believes that the benefit to the mother outweighs the potential risk to the fetus.
Doxazosin passes into breast milk in small amounts.
The use of doxazosin during breastfeeding is contraindicated.
Due to individual reactions to doxazosin, the ability to drive vehicles and operate machinery or perform certain types of work that require balance may be impaired, especially at the beginning of treatment, after dose increase, switching to another medicine, or when consuming alcohol.
If the patient has previously been diagnosed with intolerance to some sugars, they should consult their doctor before taking the medicine.
The medicine contains less than 1 mmol (23 mg) of sodium per tablet, which means that the medicine is considered "sodium-free".
This medicine should always be taken according to the doctor's instructions. In case of doubts, the patient should consult their doctor or pharmacist.
Method of administration
The medicine is taken orally. The tablets should be swallowed whole, with a glass of water.
Essential hypertension
Treatment with Doxar should be started with an initial dose of 1 mg per day. Depending on efficacy, after 1 to 2 weeks, the doctor may increase the dose to 2 mg of doxazosin per day, then to 4 mg of doxazosin per day, and finally to 8 mg of doxazosin per day.
The average maintenance dose is 2 mg to 4 mg of doxazosin per day.
The maximum recommended daily dose of the medicine is 16 mg of doxazosin.
To start treatment, the following dosing schedule is recommended:
Benign prostatic hyperplasia (BPH)
Treatment with Doxar should be started with an initial dose of 1 mg per day. If necessary, after one week, the doctor may increase the dose to 2 mg of doxazosin per day, and then to 4 mg of doxazosin per day.
The maximum recommended dose is 8 mg of doxazosin per day.
To start treatment, the following dosing schedule is recommended:
There is no need to adjust the dose of the medicine in elderly patients.
The dose of the medicine should be as low as possible, and its increase should be done under strict medical supervision.
There is no need to adjust the dose of the medicine in patients with renal impairment.
The dose of the medicine should be as low as possible, and its increase should be done under strict medical supervision.
There is a lack of clinical experience in patients with severe liver dysfunction. Caution is advised when using Doxar in patients with liver dysfunction.
Doxar is not recommended for use in children and adolescents under 18 years of age.
In case of taking a higher dose than recommended, the patient should immediately consult their doctor or pharmacist.
In case of overdose leading to hypotension (blood pressure below 100 mmHg systolic and 60 mmHg diastolic), the patient should be placed on their back with their legs elevated. Depending on the symptoms, the doctor will administer appropriate treatment.
Due to the high degree of binding of doxazosin to plasma proteins, dialysis is not recommended.
The patient should not take a double dose to make up for a missed dose.
If the patient feels that the effect of the medicine is too strong or too weak, they should consult their doctor.
In case of doubts about taking the medicine, the patient should consult their doctor or pharmacist.
Like all medicines, this medicine can cause side effects, although not everybody gets them.
if the patient experiences any of the following side effects:
The patient should immediatelyconsult their doctor if they experience any of the following side effects:
The following side effects have been reported in patients taking doxazosin:
Common side effects (occurring in 1 to 10 out of 100 patients):
Uncommon side effects (occurring in 1 to 10 out of 1,000 patients):
Rare side effects (occurring in less than 1 out of 10,000 patients):
Very rare side effects (occurring in less than 1 out of 100,000 patients):
Side effects with unknown frequency (frequency cannot be estimated from available data):
If the patient experiences any side effects, including any side effects not listed in the leaflet, they should tell their doctor or pharmacist or nurse.
Side effects can be reported directly to the Department of Drug Safety Monitoring of the Office for Registration of Medicinal Products, Medical Devices, and Biocidal Products, Al. Jerozolimskie 181C, 02-222 Warsaw, Tel.: +48 22 49 21 301, Fax: +48 22 49 21 309. Website: https://smz.ezdrowie.gov.pl
Side effects can also be reported to the marketing authorization holder.
By reporting side effects, more information can be collected on the safety of the medicine.
Store in a temperature below 25°C.
Store in a place out of sight and reach of children.
Do not use the medicine after the expiry date stated on the packaging. The expiry date refers to the last day of the given month.
Medicines should not be disposed of via wastewater or household waste. The patient should ask their pharmacist how to dispose of medicines that are no longer needed. This will help protect the environment.
The active substance of the medicine is doxazosin mesylate, which is equivalent to 1 mg, 2 mg, or 4 mg of doxazosin.
Other ingredients of the medicine are: microcrystalline cellulose, lactose, sodium carboxymethylcellulose, magnesium stearate, sodium lauryl sulfate.
White, round, biconvex tablets with a smooth surface.
Doxar, 1 mg, tablets - 30 tablets in a cardboard box.
Doxar, 2 mg, tablets - 30 tablets in a cardboard box.
Doxar, 4 mg, tablets - 30 or 120 tablets in a cardboard box.
Teva Pharmaceuticals Polska Sp. z o.o.
ul. Emilii Plater 53
00-113 Warsaw
tel. (22) 345 93 00.
Poland
Teva Operations Poland Sp. z o.o.
ul. Mogilska 80
31-546 Kraków
Poland
Date of last revision of the leaflet:April 2023
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