Silodosin 4mg Capsules
It is used to treat the signs of an enlarged prostate. If you have been given this drug for some other reason, talk with your doctor for more information.
Drug Class
Alpha-1 adrenergic blocker
Pharmacologic Class
Selective alpha-1A adrenergic receptor antagonist
Pregnancy Category
Not applicable (Not indicated for use in women)
FDA Approved
Oct 2008
DEA Schedule
Not Controlled
Overview
What is this medicine?
Silodosin is a medication used to treat symptoms of an enlarged prostate (benign prostatic hyperplasia or BPH) in men. It works by relaxing the muscles in the prostate and bladder, which helps to improve urine flow and reduce symptoms like frequent or urgent urination.
How to Use This Medicine
Taking Your Medication
To take this medication correctly, follow your doctor's instructions and read all the information provided. Take your dose with a meal to help your body absorb the medication. If you have trouble swallowing the capsule, you can sprinkle its contents onto a small amount of applesauce. However, do not chew the mixture. Instead, swallow it immediately and follow with a glass of cool water. It's essential to use cool applesauce, as warm applesauce may affect the medication. Do not mix the capsule contents with any other liquids or foods.
Storing and Disposing of Your Medication
To maintain the medication's effectiveness, store it at room temperature, away from direct light and moisture. Keep it in a dry place, such as a closet or drawer, and avoid storing it in a bathroom. Ensure that all medications are kept out of the reach of children and pets. If you have unused or expired medication, dispose of it properly. Do not flush it down the toilet or pour it down the drain unless instructed to do so by your pharmacist. Check with your pharmacist for guidance on the best disposal method, as there may be drug take-back programs available in your area.
Missing a Dose
If you miss a dose, take it as soon as you remember, with a meal. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
To take this medication correctly, follow your doctor's instructions and read all the information provided. Take your dose with a meal to help your body absorb the medication. If you have trouble swallowing the capsule, you can sprinkle its contents onto a small amount of applesauce. However, do not chew the mixture. Instead, swallow it immediately and follow with a glass of cool water. It's essential to use cool applesauce, as warm applesauce may affect the medication. Do not mix the capsule contents with any other liquids or foods.
Storing and Disposing of Your Medication
To maintain the medication's effectiveness, store it at room temperature, away from direct light and moisture. Keep it in a dry place, such as a closet or drawer, and avoid storing it in a bathroom. Ensure that all medications are kept out of the reach of children and pets. If you have unused or expired medication, dispose of it properly. Do not flush it down the toilet or pour it down the drain unless instructed to do so by your pharmacist. Check with your pharmacist for guidance on the best disposal method, as there may be drug take-back programs available in your area.
Missing a Dose
If you miss a dose, take it as soon as you remember, with a meal. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Take silodosin once daily with a meal, at approximately the same time each day.
- Avoid sudden changes in position (e.g., standing up quickly from a sitting or lying position) to minimize dizziness or lightheadedness.
- Be aware that silodosin can cause a decrease or absence of semen during ejaculation (retrograde ejaculation), which is generally harmless but can be bothersome.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
8 mg once daily with a meal (e.g., two 4 mg capsules)
Dose Range:
4 - 8 mg
Condition-Specific Dosing:
moderateRenalImpairment:
4 mg once daily with a meal
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established
Dose Adjustments
Renal Impairment:
Mild:
No dose adjustment required (CrCl 50-79 mL/min)
Moderate:
Reduce dose to 4 mg once daily with a meal (CrCl 30-49 mL/min)
Severe:
Contraindicated (CrCl <30 mL/min)
Dialysis:
Contraindicated
Hepatic Impairment:
Mild:
No dose adjustment required
Moderate:
No dose adjustment required
Severe:
Not studied; not recommended
Pharmacology
Mechanism of Action
Silodosin is a selective antagonist of alpha-1A adrenergic receptors, which are predominantly located in the human prostate, bladder base, bladder neck, prostatic capsule, and prostatic urethra. Blockade of these alpha-1A adrenergic receptors causes relaxation of the smooth muscle in these tissues, thereby decreasing bladder outlet obstruction and improving urinary flow in patients with benign prostatic hyperplasia (BPH).
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 32%
Tmax:
2.5-4.9 hours
FoodEffect:
Administration with a high-fat meal decreases Cmax by approximately 18% and increases Tmax to 4.7 hours. Should be taken with a meal.
Distribution:
Vd:
49.5 L
ProteinBinding:
95.6% (primarily to alpha-1 acid glycoprotein)
CnssPenetration:
Limited
Elimination:
HalfLife:
Approximately 13.3 hours (silodosin); approximately 24 hours (KMD-3213G)
Clearance:
Not available
ExcretionRoute:
Urine (33.5%), feces (54.9%)
Unchanged:
Approximately 3.4% (urine), 2.1% (feces)
Pharmacodynamics
OnsetOfAction:
Symptomatic improvement may be observed within a week of initiation.
PeakEffect:
Not a single peak effect; sustained improvement in urinary flow and BPH symptoms with continued daily dosing.
DurationOfAction:
24 hours (supports once-daily dosing)
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, including:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Severe dizziness or fainting
Other Possible Side Effects
Like all medications, this drug can cause side effects. Although many people may not experience any side effects or only mild ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms that bother you or persist, contact your doctor for guidance:
Orgasm with reduced or absent semen
Dizziness
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects not mentioned here. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, including:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Severe dizziness or fainting
Other Possible Side Effects
Like all medications, this drug can cause side effects. Although many people may not experience any side effects or only mild ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms that bother you or persist, contact your doctor for guidance:
Orgasm with reduced or absent semen
Dizziness
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects not mentioned here. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe dizziness or fainting (syncope)
- Chest pain or shortness of breath
- Prolonged, painful erection (priapism) lasting more than 4 hours â seek immediate medical attention
- Severe allergic reaction (rash, itching, swelling, severe dizziness, trouble breathing)
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the allergic reaction you experienced.
If you have kidney disease or liver disease, as these conditions may affect how your body processes the medication.
Any medications you are currently taking, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins. Certain medications, such as those used to treat HIV, infections, depression, and other conditions, should not be taken with this drug. Your doctor or pharmacist can help you determine if any of your medications interact with this one.
If you are using a medication similar to this one, or if you are unsure, consult with your doctor or pharmacist to confirm.
If you are pregnant, plan to become pregnant, or are breastfeeding. This medication is not approved for use in these situations, so it is crucial to discuss your options with your doctor.
Please note that this is not an exhaustive list of all potential interactions or health problems that may be affected by this medication. To ensure your safety, it is vital to:
Inform your doctor and pharmacist about all your medications (prescription and OTC), natural products, vitamins, and health problems.
Verify that it is safe to take this medication with all your other medications and health conditions.
Never start, stop, or change the dose of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the allergic reaction you experienced.
If you have kidney disease or liver disease, as these conditions may affect how your body processes the medication.
Any medications you are currently taking, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins. Certain medications, such as those used to treat HIV, infections, depression, and other conditions, should not be taken with this drug. Your doctor or pharmacist can help you determine if any of your medications interact with this one.
If you are using a medication similar to this one, or if you are unsure, consult with your doctor or pharmacist to confirm.
If you are pregnant, plan to become pregnant, or are breastfeeding. This medication is not approved for use in these situations, so it is crucial to discuss your options with your doctor.
Please note that this is not an exhaustive list of all potential interactions or health problems that may be affected by this medication. To ensure your safety, it is vital to:
Inform your doctor and pharmacist about all your medications (prescription and OTC), natural products, vitamins, and health problems.
Verify that it is safe to take this medication with all your other medications and health conditions.
Never start, stop, or change the dose of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
When starting this medication, avoid driving and other activities that require alertness until you understand how it affects you. To minimize the risk of dizziness or fainting, get up slowly from a sitting or lying position. Be cautious when climbing stairs.
If you are scheduled for cataract surgery or any other eye procedure, discuss this with your doctor beforehand.
Follow your doctor's instructions for regular blood tests and other laboratory evaluations. Additionally, monitor your blood pressure as advised by your doctor.
Men should undergo a rectal exam to check the prostate gland and have a prostate-specific antigen (PSA) blood test. Discuss these tests with your doctor.
Before consuming alcohol, consult with your doctor to understand any potential interactions with this medication.
Animal studies have shown that this drug can cause fertility problems in male rats, which resolved after the medication was stopped. However, it is unknown whether this medication will have a similar effect on human fertility.
When starting this medication, avoid driving and other activities that require alertness until you understand how it affects you. To minimize the risk of dizziness or fainting, get up slowly from a sitting or lying position. Be cautious when climbing stairs.
If you are scheduled for cataract surgery or any other eye procedure, discuss this with your doctor beforehand.
Follow your doctor's instructions for regular blood tests and other laboratory evaluations. Additionally, monitor your blood pressure as advised by your doctor.
Men should undergo a rectal exam to check the prostate gland and have a prostate-specific antigen (PSA) blood test. Discuss these tests with your doctor.
Before consuming alcohol, consult with your doctor to understand any potential interactions with this medication.
Animal studies have shown that this drug can cause fertility problems in male rats, which resolved after the medication was stopped. However, it is unknown whether this medication will have a similar effect on human fertility.
Overdose Information
Overdose Symptoms:
- Severe hypotension (low blood pressure)
- Dizziness
- Fainting
What to Do:
In case of overdose, contact a poison control center immediately (e.g., Call 1-800-222-1222 in the US) or seek emergency medical attention. Management is supportive, focusing on maintaining cardiovascular stability (e.g., keeping patient supine, administering fluids, vasopressors if needed).
Drug Interactions
Contraindicated Interactions
- Strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin, ritonavir)
- Other alpha-adrenergic blocking agents
Major Interactions
- PDE5 inhibitors (e.g., sildenafil, tadalafil) - risk of symptomatic orthostasis
- Moderate CYP3A4 inhibitors (e.g., diltiazem, erythromycin)
Moderate Interactions
- Antihypertensive medications (additive hypotensive effects)
Minor Interactions
- Not available
Monitoring
Baseline Monitoring
Blood Pressure (Orthostatic)
Rationale: To assess baseline risk for orthostatic hypotension.
Timing: Prior to initiation of therapy.
Renal Function (Creatinine Clearance)
Rationale: To determine appropriate dosing, as dose adjustment is needed for moderate renal impairment and contraindicated in severe impairment.
Timing: Prior to initiation of therapy.
Routine Monitoring
Blood Pressure (Orthostatic)
Frequency: Periodically, especially during initial therapy and dose titration.
Target: Maintain within patient's normal limits, without symptomatic hypotension.
Action Threshold: Symptomatic orthostatic hypotension (dizziness, lightheadedness, syncope) requires re-evaluation of therapy.
BPH Symptom Assessment (e.g., AUA Symptom Score)
Frequency: Periodically, to assess therapeutic efficacy.
Target: Improvement in urinary flow and reduction in BPH symptoms.
Action Threshold: Lack of symptomatic improvement may warrant re-evaluation of diagnosis or alternative therapy.
Ejaculatory Function
Frequency: As needed, if patient reports issues.
Target: Not applicable
Action Threshold: Retrograde ejaculation is a common side effect; discuss with patient if bothersome.
Symptom Monitoring
- Dizziness
- Lightheadedness
- Fainting (syncope)
- Headache
- Nasal congestion
- Diarrhea
- Retrograde ejaculation (reduced or absent semen during orgasm)
- Priapism (prolonged, painful erection)
Special Patient Groups
Pregnancy
Silodosin is not indicated for use in women. There are no data on silodosin use in pregnant women.
Trimester-Specific Risks:
First Trimester:
Not applicable
Second Trimester:
Not applicable
Third Trimester:
Not applicable
Lactation
Silodosin is not indicated for use in women. It is unknown if silodosin is excreted in human milk.
Infant Risk:
Not applicable
Pediatric Use
The safety and effectiveness of silodosin in pediatric patients have not been established. Silodosin is not indicated for use in pediatric patients.
Geriatric Use
No overall differences in safety or effectiveness were observed between elderly (âĨ65 years) and younger patients. However, the incidence of orthostatic hypotension was higher in elderly patients. No dose adjustment is required based on age alone, but careful monitoring for orthostatic symptoms is recommended.
Clinical Information
Clinical Pearls
- Silodosin is highly selective for alpha-1A receptors, which may contribute to a lower incidence of cardiovascular side effects compared to non-selective alpha-blockers, but orthostatic hypotension can still occur.
- Retrograde ejaculation is a common and often bothersome side effect (reported in up to 28% of patients in clinical trials), which should be discussed with patients prior to initiation.
- Patients should be advised to take silodosin with a meal to optimize absorption and reduce the risk of gastrointestinal upset.
- Caution is advised when co-administering with PDE5 inhibitors due to the potential for additive hypotensive effects.
Alternative Therapies
- Other alpha-adrenergic blockers (e.g., tamsulosin, alfuzosin, doxazosin, terazosin)
- 5-alpha reductase inhibitors (e.g., finasteride, dutasteride)
- Phosphodiesterase-5 (PDE5) inhibitors (e.g., tadalafil for BPH and ED)
- Combination therapy (e.g., alpha-blocker + 5-ARI)
- Surgical interventions (e.g., TURP, laser prostatectomy)
Cost & Coverage
Average Cost:
Varies, typically $100-$300 per 30 capsules
Generic Available:
Yes
Insurance Coverage:
Tier 2 or Tier 3 (preferred brand or non-preferred brand, respectively)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.