Doxazosin Actavis (Doxazosin) 4 mg Extended-Release Tablets
Alpha-blocker for high blood pressure and enlarged prostate (BPH)
Quick Facts: Doxazosin Actavis
Key Takeaways About Doxazosin Actavis
- Dual action: Doxazosin Actavis treats both high blood pressure and enlarged prostate symptoms simultaneously in a single daily dose
- First-dose effect: Dizziness and lightheadedness can occur when starting treatment or increasing the dose — rise slowly from sitting or lying positions
- Cataract surgery alert: Always inform your eye surgeon that you take or have taken doxazosin before cataract surgery due to risk of Intraoperative Floppy Iris Syndrome (IFIS)
- Extended-release design: Swallow the tablet whole — do not chew, crush, or split it. The empty shell may appear in your stool, which is normal
- Drug interactions: Use caution with PDE5 inhibitors (sildenafil, tadalafil, vardenafil) and other blood pressure medications, as combined use can cause significant blood pressure drops
What Is Doxazosin Actavis and What Is It Used For?
Doxazosin Actavis is an alpha-1 adrenergic receptor blocker (alpha-blocker) used to treat high blood pressure (hypertension) and to relieve urinary symptoms caused by an enlarged prostate (benign prostatic hyperplasia, or BPH). It is available as extended-release tablets containing 4 mg of doxazosin.
Doxazosin belongs to a class of medications known as alpha-1 adrenergic receptor antagonists, commonly referred to as alpha-blockers. This medication works by selectively blocking alpha-1 receptors found on the smooth muscle cells of blood vessels and in the prostate gland. By blocking these receptors, doxazosin causes the smooth muscle to relax, which produces its therapeutic effects in both hypertension and BPH.
For the treatment of high blood pressure, doxazosin works by relaxing and widening blood vessels, thereby reducing the resistance to blood flow. This allows blood to flow more easily through the circulatory system and results in a lowering of blood pressure. Untreated high blood pressure increases the risk of serious cardiovascular events, including heart attack, stroke, and kidney damage. Doxazosin helps to reduce these risks by keeping blood pressure within a healthy range.
For men with benign prostatic hyperplasia (BPH), doxazosin helps to relieve troublesome urinary symptoms. As the prostate gland enlarges, it can compress the urethra and the bladder neck, making urination difficult. Common BPH symptoms include a weak urine stream, frequent urination (especially at night), difficulty starting urination, and a sensation that the bladder has not emptied completely. Doxazosin relaxes the smooth muscle in the prostate capsule and bladder neck, making it easier for urine to pass through. Importantly, doxazosin does not shrink the prostate itself but improves symptoms by reducing muscle tension around the urinary tract.
The extended-release formulation of Doxazosin Actavis is specifically designed to release the active ingredient gradually over a 24-hour period. This provides a more consistent blood level of the medication throughout the day, which can reduce the peak-and-trough fluctuations seen with immediate-release formulations and potentially lower the incidence of side effects such as dizziness and hypotension.
If you are a man who has both high blood pressure and BPH, Doxazosin Actavis can treat both conditions simultaneously with a single daily tablet. This simplifies your medication regimen and reduces the total number of pills you need to take each day.
What Should You Know Before Taking Doxazosin Actavis?
Do not take Doxazosin Actavis if you are allergic to doxazosin, other quinazolines (prazosin, terazosin), or any of its ingredients. Special caution is needed if you have heart failure, liver impairment, are taking PDE5 inhibitors, or are scheduled for cataract surgery.
Before starting Doxazosin Actavis, it is essential to discuss your complete medical history with your prescribing healthcare provider. Several conditions may make this medication inappropriate for you, or may require additional monitoring during treatment. Your doctor will weigh the benefits of treatment against potential risks and decide whether doxazosin is the right choice for your situation.
Contraindications
You should not take Doxazosin Actavis if any of the following apply to you:
- Allergy to doxazosin or related medications: If you are allergic to doxazosin, other quinazolines (such as prazosin or terazosin), or any other ingredient in the tablet. Allergic reactions may include skin rash, itching, breathing difficulties, or swelling of the face, lips, throat, or tongue.
- BPH with urinary complications: If you have benign prostatic hyperplasia with bladder stones, urinary tract obstruction, or urinary tract infection.
- BPH with urinary retention: If you have BPH with overflow incontinence, inability to produce urine (anuria), or progressive kidney deterioration.
- Gastrointestinal obstruction: If you have any type of narrowing or blockage in the gastrointestinal tract, as the extended-release tablet shell may not pass safely.
- History of orthostatic hypotension: If you have previously experienced drops in blood pressure when standing or sitting up quickly (relevant particularly for BPH treatment in the absence of hypertension).
- Low blood pressure: If you have abnormally low blood pressure (hypotension) — this applies particularly if you are being treated for BPH only.
Warnings and Precautions
Talk to your doctor or pharmacist before taking Doxazosin Actavis if any of the following situations apply to you:
- Postural hypotension at treatment start: When you first begin taking doxazosin, you may experience a drop in blood pressure upon standing up from a sitting or lying position. This can cause dizziness, lightheadedness, or in some cases, fainting. Your doctor will monitor your blood pressure during the initial phase of treatment. Rise slowly and sit on the edge of the bed for a few minutes before standing up.
- Heart failure or pulmonary oedema: Use with caution if you have acute heart failure with swelling or fluid accumulation in the lungs, or if heart failure is caused by a blood clot or fluid around the heart (pericardial effusion).
- Liver impairment: If you have significantly reduced liver function, your doctor may prescribe a lower dose, as doxazosin is primarily metabolised by the liver.
- PDE5 inhibitors for erectile dysfunction: If you are taking medications for erectile dysfunction containing sildenafil, tadalafil, or vardenafil, the combination with doxazosin can lead to significant drops in blood pressure. Your doctor will advise you on appropriate timing between the two medications.
- Cataract surgery: If you are scheduled for eye surgery for cataracts, inform your ophthalmologist that you are taking or have previously taken doxazosin. This medication can cause a condition called Intraoperative Floppy Iris Syndrome (IFIS) during surgery. If your surgeon is aware in advance, they can take appropriate precautions.
- Recent surgery: If you have recently undergone any surgical procedure, discuss this with your doctor before starting treatment.
- Prostate cancer screening: Before starting doxazosin for BPH symptoms, your doctor may run tests to rule out prostate cancer, which can produce similar symptoms.
Doxazosin Actavis is an extended-release tablet enclosed in a non-absorbable shell designed to slowly release the medication into your body. After the drug has been absorbed, the empty shell passes through your digestive system. You may occasionally see what looks like a tablet in your stool — this is completely normal and expected. The medication has already been absorbed into your body.
Pregnancy and Breastfeeding
If you are pregnant, breastfeeding, think you may be pregnant, or are planning to have a baby, consult your doctor or pharmacist before taking Doxazosin Actavis. The safety of doxazosin during pregnancy has not been fully established, and it should only be used if the potential benefit justifies the potential risk to the foetus.
Small amounts of doxazosin, the active substance in Doxazosin Actavis, can be excreted in breast milk. You should not take Doxazosin Actavis while breastfeeding unless your doctor specifically advises you to do so. Your healthcare provider will help you weigh the benefits of breastfeeding against the benefits of medication treatment to make the best decision for you and your child.
Driving and Operating Machinery
Exercise caution when driving or operating machinery while taking Doxazosin Actavis. The medication can affect your ability to perform these activities safely, particularly at the beginning of treatment or when the dose is increased. Dizziness, drowsiness, and lightheadedness are common side effects that may impair your reactions. Do not drive or operate heavy machinery if you feel affected by the medication, and contact your doctor promptly if these effects persist.
Sodium Content
Doxazosin Actavis contains less than 1 mmol sodium (23 mg) per extended-release tablet, meaning it is essentially sodium-free. This is relevant for patients on a controlled sodium diet.
How Does Doxazosin Actavis Interact with Other Drugs?
Doxazosin Actavis can interact with PDE5 inhibitors (Viagra, Cialis), other blood pressure medications, certain antibiotics, antifungals, HIV medications, and the antidepressant nefazodone. These interactions may increase the risk of low blood pressure or alter how doxazosin works in your body.
It is important to tell your doctor or pharmacist about all medications you are currently taking, have recently taken, or might take. Certain drug combinations with doxazosin can lead to significant interactions that may affect your health. Your doctor may need to adjust dosages or monitor you more closely if you are taking any of the medications listed below.
Major Interactions
The following drug interactions are considered significant and require careful medical management:
| Interacting Drug | Drug Class | Effect | Clinical Advice |
|---|---|---|---|
| Sildenafil (Viagra) | PDE5 Inhibitor | Significant blood pressure drop | Stabilise doxazosin dose first; your doctor will advise on timing |
| Tadalafil (Cialis) | PDE5 Inhibitor | Significant blood pressure drop | Stabilise doxazosin dose first; your doctor will advise on timing |
| Vardenafil (Levitra) | PDE5 Inhibitor | Significant blood pressure drop | Stabilise doxazosin dose first; your doctor will advise on timing |
| Other antihypertensives | Blood pressure medications | Enhanced blood pressure lowering | Close blood pressure monitoring; dose adjustment may be needed |
Moderate Interactions
The following medications may also interact with doxazosin and should be reported to your healthcare provider:
| Interacting Drug | Drug Class | Effect | Clinical Advice |
|---|---|---|---|
| Clarithromycin | Macrolide antibiotic | May increase doxazosin blood levels | Monitor for increased side effects |
| Ketoconazole, Itraconazole, Voriconazole | Azole antifungals | May increase doxazosin blood levels | Monitor for increased side effects |
| Ritonavir, Indinavir, Nelfinavir, Saquinavir | HIV protease inhibitors | May increase doxazosin blood levels | Dose adjustment may be necessary |
| Telithromycin | Ketolide antibiotic | May increase doxazosin blood levels | Monitor blood pressure closely |
| Nefazodone | Antidepressant | May increase doxazosin blood levels | Monitor for dizziness and hypotension |
Some patients treated with alpha-blockers for high blood pressure or prostate enlargement may experience dizziness or lightheadedness due to blood pressure drops when sitting or standing up quickly. These symptoms have been observed particularly when PDE5 inhibitors for erectile dysfunction are used at the same time as alpha-blockers. To minimise the risk, you should be on a stable, regular daily dose of your alpha-blocker before starting any erectile dysfunction medication.
What Is the Correct Dosage of Doxazosin Actavis?
The recommended dose for both high blood pressure and BPH is 4 mg (one extended-release tablet) once daily. The dose may be increased to 8 mg (two tablets) once daily if needed. Tablets must be swallowed whole with water — do not chew, crush, or split them.
Always take Doxazosin Actavis exactly as your doctor or pharmacist has instructed. If you are unsure about your dose, consult your doctor or pharmacist. The tablets should be swallowed whole with a glass of water. Do not chew, divide, or crush the extended-release tablets, as this would destroy the controlled-release mechanism and potentially release too much medication at once. The tablets can be taken with or without food.
Adults (Including Elderly)
High Blood Pressure (Hypertension)
The recommended dose is 4 mg doxazosin (1 extended-release tablet) once daily. If blood pressure control is insufficient after an appropriate interval, your doctor may increase the dose to 8 mg (2 tablets) once daily. It may take up to 4 weeks for the full blood pressure-lowering effect to be achieved.
Benign Prostatic Hyperplasia (BPH)
The recommended dose is 4 mg doxazosin (1 extended-release tablet) once daily. If symptom relief is not sufficient, your doctor may increase the dose to 8 mg (2 tablets) once daily. Your doctor will review your symptoms periodically to ensure the medication continues to be effective.
Patients with Liver Impairment
If you have impaired liver function, a lower dose may be necessary. Your doctor will determine the appropriate dose based on your level of liver function. Always follow your doctor’s specific instructions regarding dosage.
Children and Adolescents
Doxazosin Actavis is not recommended for use in children or adolescents under 18 years of age. The safety and efficacy of doxazosin in this age group have not been established.
Missed Dose
If you forget to take a dose, take it as soon as you remember — unless it is almost time for your next dose. In that case, skip the missed dose and take your next dose at the regular time. Do not take a double dose to make up for a forgotten dose.
Overdose
If you have taken more Doxazosin Actavis than you should, or if someone (such as a child) has accidentally ingested the medication, contact your doctor, hospital, or poison control centre immediately for assessment and advice.
- Severe headache, dizziness, or fainting
- Loss of consciousness
- Breathing difficulties
- Dangerously low blood pressure
- Palpitations or rapid/irregular heartbeat
- Nausea
Seek emergency medical attention immediately if an overdose is suspected.
Stopping Treatment
Continue taking Doxazosin Actavis for the entire duration prescribed by your doctor. Do not stop taking it or change the dose without first consulting your healthcare provider. Stopping abruptly could lead to a rebound increase in blood pressure or return of BPH symptoms.
What Are the Side Effects of Doxazosin Actavis?
The most common side effects of Doxazosin Actavis include dizziness, headache, fatigue, drowsiness, swelling in the legs, respiratory tract infection, and urinary tract infection. Dizziness is especially common when standing up quickly at the start of treatment. Serious but rare side effects include allergic reactions, heart attack, and hepatitis.
Like all medicines, Doxazosin Actavis can cause side effects, although not everybody gets them. Most side effects are mild to moderate and tend to improve as your body adjusts to the medication. However, some side effects require immediate medical attention.
- Signs of a severe allergic reaction: rash, swelling of the face, lips, tongue, or throat, difficulty breathing or swallowing
- Signs of a heart attack: severe chest pain, pain radiating to arm or jaw, shortness of breath, sweating
- Signs of hepatitis or jaundice: yellowing of the skin or whites of the eyes, dark urine, nausea, vomiting, loss of appetite, fever
- Severe breathing difficulties or wheezing
Common Side Effects
May affect up to 1 in 10 people
- Respiratory tract infection, urinary tract infection
- Dizziness, weakness, and rarely fainting
- Headache, drowsiness
- Balance disturbance when rising quickly (postural hypotension)
- Palpitations (awareness of heartbeat) or faster heartbeat
- Low blood pressure
- Vertigo (spinning sensation), especially when rising quickly
- Bronchitis, cough, shortness of breath
- Runny or blocked nose, sneezing, facial pressure or pain
- Abdominal pain, indigestion, heartburn, dry mouth, nausea
- Itching
- Back pain, muscle pain
- Bladder inflammation (cystitis), urinary incontinence
- Chest pain, weakness and lack of energy
- Fluid retention in the legs (oedema)
- Flu-like symptoms
Uncommon Side Effects
May affect up to 1 in 100 people
- Decreased or increased appetite, gout
- Anxiety, depression, insomnia
- Stroke, reduced sensation of touch, loss of consciousness, fainting
- Tremor, involuntary shaking
- Tinnitus (ringing in the ears)
- Angina (chest pain from heart)
- Constipation, nosebleeds, flatulence, vomiting, diarrhoea
- Abnormal liver values (detected in blood tests), gastroenteritis
- Skin rash, joint pain
- Blood in urine, painful urination, frequent urination
- Erectile dysfunction (impotence)
- Facial swelling, weight gain, pain
Rare Side Effects
May affect up to 1 in 1,000 people
- Gastrointestinal obstruction (blockage in the digestive tract)
Very Rare Side Effects
May affect up to 1 in 10,000 people
- Decreased white blood cells (may lead to more infections) or platelets (may cause more bruising or bleeding)
- Agitation, nervousness, numbness
- Positional dizziness, blurred vision
- Slower heartbeat, irregular heartbeat
- Airway constriction (asthma-like symptoms)
- Poor bile flow (cholestasis), flushing
- Hair loss (alopecia), itchy rash, skin discolouration (purpura)
- Muscle cramps, muscle weakness, tingling and pins-and-needles
- Frequent night-time urination, increased urine production, urination problems
- Priapism (prolonged, painful erection — seek immediate medical attention)
- Gynaecomastia (breast enlargement in men)
- Fatigue, general malaise
Intraoperative Floppy Iris Syndrome (IFIS) — a variant of small pupil syndrome that can develop during cataract surgery in patients who are taking or have previously taken alpha-blockers including doxazosin. Retrograde ejaculation — a condition where semen enters the bladder instead of being ejaculated through the urethra. Both conditions should be discussed with your doctor.
How Should You Store Doxazosin Actavis?
No special storage conditions are required. Keep out of sight and reach of children. Do not use after the expiry date stated on the blister pack and carton. Dispose of unused medication through your local pharmacy.
Doxazosin Actavis does not require any special storage conditions. Store the medication at room temperature and keep it in its original packaging to protect it from light and moisture. As with all medications, keep it out of the sight and reach of children to prevent accidental ingestion.
Do not use Doxazosin Actavis after the expiry date printed on the blister pack and carton after “EXP”. The expiry date refers to the last day of the stated month. Do not dispose of medications via wastewater or household waste. Ask your pharmacist about proper disposal methods for medications that are no longer needed. These measures help to protect the environment.
What Does Doxazosin Actavis Contain?
Each extended-release tablet contains doxazosin mesilate 4.85 mg, equivalent to 4 mg doxazosin. The tablet is white, round, and biconvex with the imprint “DL”.
The active substance is doxazosin. Each extended-release tablet contains doxazosin mesilate 4.85 mg, which corresponds to 4 mg of doxazosin base. Doxazosin mesilate is the salt form of the active drug, which improves its stability and absorption characteristics.
The other ingredients (excipients) are: polyethylene oxide, microcrystalline cellulose, povidone K29-32, butylated hydroxytoluene (E321), all-rac-alpha-tocopherol, colloidal hydrated silica, sodium stearyl fumarate, methacrylic acid-ethyl acrylate copolymer, macrogol 1300-1600, and titanium dioxide (E171). These ingredients form the tablet matrix and the non-absorbable shell that controls the release of the medication.
Appearance: Doxazosin Actavis extended-release tablets are white, round, biconvex tablets marked with “DL”. They are available in pack sizes of 10, 28, 30, 50, 90, 98, or 100 extended-release tablets. Not all pack sizes may be marketed in all countries.
Frequently Asked Questions About Doxazosin Actavis
References and Sources
This article is based on the following evidence-based sources and international medical guidelines:
- European Medicines Agency (EMA). Doxazosin – Summary of Product Characteristics. EMA/CHMP. Available at: ema.europa.eu
- British National Formulary (BNF). Doxazosin. NICE Evidence Services, 2025. Available at: bnf.nice.org.uk
- World Health Organization (WHO). WHO Model List of Essential Medicines – 23rd List, 2023. WHO Technical Report Series.
- National Institute for Health and Care Excellence (NICE). Hypertension in adults: diagnosis and management. NICE guideline [NG136], updated 2022.
- American Urological Association (AUA). Management of Benign Prostatic Hyperplasia (BPH). AUA Clinical Guidelines, 2021.
- European Association of Urology (EAU). Guidelines on Management of Non-neurogenic Male Lower Urinary Tract Symptoms (LUTS), incl. Benign Prostatic Obstruction (BPO). 2024 Update.
- Lepor H. Alpha-blockers for the treatment of benign prostatic hyperplasia. Urologic Clinics of North America. 2016;43(3):311-323.
- Chang DF, Campbell JR. Intraoperative floppy iris syndrome associated with tamsulosin (Flomax) and other alpha-1 adrenergic receptor antagonists. J Cataract Refract Surg. 2005;31(7):1403-1410.
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This article has been written, fact-checked, and medically reviewed by the iMedic Medical Editorial Team, consisting of licensed physicians, pharmacists, and specialists in internal medicine and pharmacology.
Medical Writers
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Last medical review: | Next scheduled review: | Evidence level: 1A (systematic reviews and RCTs)