Usage
Alfuzosin is prescribed for the treatment of symptoms associated with benign prostatic hyperplasia (BPH), also known as an enlarged prostate. These symptoms include difficulty urinating, weak stream, and the need to urinate frequently or urgently. It belongs to the pharmacological class of alpha-1 adrenergic antagonists. Alfuzosin works by relaxing the muscles in the prostate and bladder neck, making it easier to urinate.
Alternate Names
Alfuzosin hydrochloride is the chemical name. It is marketed under various brand names, including Uroxatral and Xatral.
How It Works
Pharmacodynamics: Alfuzosin is a selective alpha-1a adrenergic receptor antagonist. It blocks the action of norepinephrine on these receptors located in the smooth muscle of the prostate, bladder neck, and prostatic urethra. This blockade leads to smooth muscle relaxation, reducing urethral resistance and improving urine flow.
Pharmacokinetics:
- Absorption: Alfuzosin is well-absorbed after oral administration, reaching peak plasma concentration in about 1.5 to 3 hours for the immediate-release formulation and 8-9 hours for the extended-release formulation. Food can increase the absorption of alfuzosin.
- Metabolism: It undergoes extensive metabolism in the liver, primarily by CYP3A4 enzymes.
- Elimination: Alfuzosin is eliminated primarily through the kidneys, with a smaller portion excreted in the feces. The half-life is about 5 to 8 hours for the immediate-release formulation and around 10 hours for the extended-release formulation.
Mode of Action: By selectively blocking alpha-1a adrenergic receptors, alfuzosin relaxes the smooth muscle of the lower urinary tract, reducing urethral resistance and improving urinary symptoms in BPH.
Dosage
Standard Dosage
Adults:
The standard dose of the extended-release formulation is 10 mg orally once a day, taken immediately after the same meal each day. The immediate-release formulation is given at 2.5 mg three times per day up to a maximum of 10mg/day.
Children:
Alfuzosin is not recommended for use in children.
Special Cases:
- Elderly Patients: The starting dose for elderly patients may be lower (5 mg extended-release daily for a few days) and increased up to the standard dose of 10 mg.
- Patients with Renal Impairment: Caution is advised in patients with severe renal impairment (creatinine clearance less than 30 mL/minute). Dose adjustments may be necessary.
- Patients with Hepatic Dysfunction: Alfuzosin is contraindicated in patients with moderate to severe hepatic impairment.
- Patients with Comorbid Conditions: Caution should be exercised in patients with cardiovascular diseases, especially those taking antihypertensive medications or nitrates.
Clinical Use Cases
Alfuzosin’s primary use is in the management of BPH. It is not typically used in clinical settings such as intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations.
Dosage Adjustments
Dose modifications may be necessary for patients with renal or hepatic impairment and those taking interacting medications, particularly CYP3A4 inhibitors or other alpha-1 blockers.
Side Effects
Common Side Effects:
Dizziness, headache, tiredness, runny or stuffy nose, nausea, and decreased sexual ability.
Rare but Serious Side Effects:
Orthostatic hypotension (a sudden drop in blood pressure upon standing), fainting, severe allergic reactions (including swelling of the face, lips, tongue, or throat), and priapism (prolonged and painful erection).
Long-Term Effects:
Long-term side effects are generally uncommon but can include chronic dizziness and sexual dysfunction.
Adverse Drug Reactions (ADR):
Clinically significant ADRs include severe allergic reactions, orthostatic hypotension, and priapism.
Contraindications
- Hypersensitivity to alfuzosin or other quinazolines.
- Moderate to severe hepatic impairment.
- Concurrent use of potent CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, ritonavir) or other alpha-1 blockers.
- History of orthostatic hypotension.
Drug Interactions
Alfuzosin interacts with numerous medications:
- CYP3A4 Inhibitors: These drugs (e.g., ketoconazole, itraconazole, ritonavir) can increase alfuzosin levels and should be avoided.
- Antihypertensives and Nitrates: These can enhance the hypotensive effects of alfuzosin, requiring blood pressure monitoring.
- Other Alpha-1 Blockers: Concurrent use can lead to additive hypotensive effects and should be avoided.
- PDE5 Inhibitors: Co-administration may increase the risk of hypotension and should be done with caution.
Other interactions include certain antivirals, antifungals, and antipsychotics.
Pregnancy and Breastfeeding
Alfuzosin is not indicated for use in women and should be avoided during pregnancy and breastfeeding.
Drug Profile Summary
- Mechanism of Action: Alpha-1a adrenergic receptor antagonist, relaxing smooth muscle in the prostate and bladder neck.
- Side Effects: Dizziness, headache, tiredness, orthostatic hypotension, allergic reactions, priapism.
- Contraindications: Hypersensitivity, hepatic impairment, concurrent use of CYP3A4 inhibitors or other alpha-1 blockers.
- Drug Interactions: CYP3A4 inhibitors, antihypertensives, nitrates, other alpha-1 blockers, PDE5 inhibitors.
- Pregnancy & Breastfeeding: Contraindicated.
- Dosage: 10 mg extended-release orally once daily or 2.5mg immediate release tablets three times per day up to 10mg per day.
- Monitoring Parameters: Blood pressure, especially in patients taking antihypertensives or with a history of hypotension.
Popular Combinations
Alfuzosin is sometimes used in combination with other medications for BPH, such as 5-alpha reductase inhibitors (e.g., finasteride, dutasteride), though combination therapy should be carefully considered due to the potential for additive effects and side effects.
Precautions
- Patients should be monitored for orthostatic hypotension, especially at the start of treatment.
- Patients should inform their eye doctor about alfuzosin use before cataract surgery due to the risk of intraoperative floppy iris syndrome.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Alfuzosin?
A: The standard dose of alfuzosin extended-release is 10 mg orally once a day, taken after the same meal each day. The immediate release formulation is given as 2.5mg three times per day up to 10mg per day. Dosage adjustments might be needed for elderly patients or those with renal impairment.
Q2: What are the most common side effects of Alfuzosin?
A: Dizziness, headache, tiredness, and runny or stuffy nose are common side effects.
Q3: Can Alfuzosin be used with other alpha-blockers?
A: No, Alfuzosin should not be combined with other alpha-blockers as this may result in additive hypotensive effects.
Q4: What should I do if I experience dizziness after taking Alfuzosin?
A: If you experience dizziness, lie down with your legs elevated until the symptoms subside. Contact your doctor if dizziness persists or is severe.
Q5: Is Alfuzosin safe for patients with liver problems?
A: Alfuzosin is contraindicated in patients with moderate to severe hepatic impairment.
Q6: Can Alfuzosin affect sexual function?
A: Yes, some patients experience decreased sexual ability while taking alfuzosin, including retrograde ejaculation. It should be noted that alfuzosin can improve ejaculatory and other sexual functions in some men.
Q7: Should Alfuzosin be taken on an empty stomach?
A: No, Alfuzosin should be taken immediately after a meal, preferably the same meal each day, to enhance absorption and reduce the risk of side effects like dizziness.
A: Serious side effects requiring immediate attention include severe allergic reactions (swelling of face, difficulty breathing), severe dizziness or fainting, and priapism (prolonged, painful erection).
Q9: Can I crush or chew Alfuzosin extended-release tablets?
A: No, extended-release tablets should be swallowed whole. Crushing or chewing them alters the drug’s release profile and may lead to increased side effects.
Q10: What precautions should be taken before cataract surgery in patients taking Alfuzosin?
A: Patients should inform their ophthalmologist about Alfuzosin use before cataract surgery, as it can increase the risk of Intraoperative Floppy Iris Syndrome (IFIS). The surgeon may need to adjust the surgical technique.
