Silodosin 8mg 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
Drugs for Benign Prostatic Hyperplasia
Pharmacologic Class
Alpha-1A Adrenergic Antagonist
Pregnancy Category
Not applicable
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, also known as Benign Prostatic Hyperplasia (BPH). It works by relaxing the muscles in the prostate and bladder, which helps to improve urine flow and reduce urinary symptoms like frequent urination, urgency, and difficulty starting 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. Avoid mixing the capsule contents with other liquids or foods.
Storing and Disposing of Your Medication
Store your medication 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 the bathroom. Ensure that all medications are kept out of reach of children and pets. When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless instructed to do so by your pharmacist. Instead, check with your pharmacist for guidance on the best disposal method or explore local drug take-back programs.
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. Avoid mixing the capsule contents with other liquids or foods.
Storing and Disposing of Your Medication
Store your medication 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 the bathroom. Ensure that all medications are kept out of reach of children and pets. When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless instructed to do so by your pharmacist. Instead, check with your pharmacist for guidance on the best disposal method or explore local drug take-back programs.
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 with a meal at the same time each day to help reduce the risk of dizziness or lightheadedness.
- Avoid activities that require mental alertness, such as driving or operating machinery, until you know how silodosin affects you, especially after the first dose or a dose increase.
- Be cautious when changing positions (e.g., standing up from sitting or lying down) to prevent dizziness or fainting. Get up slowly.
- Inform your eye doctor (ophthalmologist) that you are taking silodosin before any cataract or glaucoma surgery, as it can cause a condition called Intraoperative Floppy Iris Syndrome (IFIS).
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
8 mg orally once daily with a meal
Dose Range:
8 - 8 mg
Condition-Specific Dosing:
BPH:
8 mg orally 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 dosage adjustment needed (CrCl 50-80 mL/min)
Moderate:
4 mg orally once daily with a meal (CrCl 30-49 mL/min)
Severe:
Contraindicated (CrCl < 30 mL/min)
Dialysis:
Contraindicated
Hepatic Impairment:
Mild:
No dosage adjustment needed
Moderate:
No dosage adjustment needed
Severe:
Not recommended (Child-Pugh score > 9)
Pharmacology
Mechanism of Action
Silodosin is a selective antagonist of alpha-1A adrenergic receptors, which are predominantly located in the prostate, bladder base, bladder neck, prostatic capsule, and prostatic urethra. By blocking these receptors, silodosin causes relaxation of the smooth muscle in these tissues, thereby decreasing urethral resistance and improving urine flow and symptoms of benign prostatic hyperplasia (BPH).
Pharmacokinetics
Absorption:
Bioavailability:
32%
Tmax:
2.5 hours (fasted), 3.4 hours (with food)
FoodEffect:
Food reduces Cmax by approximately 18% and increases Tmax to 3.4 hours, but does not significantly affect AUC. Should be taken with a meal to reduce orthostatic symptoms.
Distribution:
Vd:
49.5 L
ProteinBinding:
96.6% (primarily to alpha-1 acid glycoprotein)
CnssPenetration:
Limited
Elimination:
HalfLife:
13.3 hours (silodosin), 24 hours (KMD-3213G)
Clearance:
Not available
ExcretionRoute:
60.4% in urine, 33.5% in feces
Unchanged:
3.4% (urine), 2.1% (feces)
Pharmacodynamics
OnsetOfAction:
Within 1 week
PeakEffect:
Within 1-2 weeks
DurationOfAction:
24 hours (with 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 immediately or seek emergency 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 advice:
Orgasm with reduced or absent semen
Dizziness
Note: 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 immediately or seek emergency 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 advice:
Orgasm with reduced or absent semen
Dizziness
Note: 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
- Priapism (painful erection lasting more than 4 hours) - seek immediate medical attention
- Allergic reaction symptoms (rash, itching, swelling of face/tongue/throat, 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, and depression, 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, as taking multiple similar medications can increase the risk of adverse effects.
If you are pregnant, plan to become pregnant, or are breastfeeding. This medication is not approved for use in these patients, and your doctor will need to discuss the potential risks and benefits with you.
Remember, this is not an exhaustive list of all potential interactions or health problems that may affect your ability to take this medication. To ensure your safety, it is crucial to:
Inform your doctor and pharmacist about all your medications, including prescription and OTC drugs, natural products, and vitamins.
Discuss all your health problems with your doctor.
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, and depression, 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, as taking multiple similar medications can increase the risk of adverse effects.
If you are pregnant, plan to become pregnant, or are breastfeeding. This medication is not approved for use in these patients, and your doctor will need to discuss the potential risks and benefits with you.
Remember, this is not an exhaustive list of all potential interactions or health problems that may affect your ability to take this medication. To ensure your safety, it is crucial to:
Inform your doctor and pharmacist about all your medications, including prescription and OTC drugs, natural products, and vitamins.
Discuss all your health problems with your doctor.
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. As directed by your doctor, regularly have your blood work and other laboratory tests checked. Additionally, monitor your blood pressure as advised by your doctor.
Men should undergo a rectal exam to check the prostate gland and have a blood test (PSA test) as recommended by their doctor. It is also important to discuss alcohol consumption with your doctor before drinking.
Note that this medication has been associated with fertility issues in male rats, which resolved after the medication was stopped. However, it is unclear if this medication can cause similar fertility problems in humans.
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. As directed by your doctor, regularly have your blood work and other laboratory tests checked. Additionally, monitor your blood pressure as advised by your doctor.
Men should undergo a rectal exam to check the prostate gland and have a blood test (PSA test) as recommended by their doctor. It is also important to discuss alcohol consumption with your doctor before drinking.
Note that this medication has been associated with fertility issues in male rats, which resolved after the medication was stopped. However, it is unclear if this medication can cause similar fertility problems in humans.
Overdose Information
Overdose Symptoms:
- Severe hypotension (low blood pressure)
- Dizziness
- Fainting
What to Do:
Call 1-800-222-1222 (Poison Control). Management is supportive, including maintaining cardiovascular stability. Patient should be kept in a supine position. If necessary, vasopressors and volume expanders may be used. Dialysis is unlikely to be beneficial due to high protein binding.
Drug Interactions
Contraindicated Interactions
- Strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin, ritonavir)
- Other alpha-adrenergic blocking agents (e.g., prazosin, tamsulosin, alfuzosin, doxazosin)
Major Interactions
- Moderate CYP3A4 inhibitors (e.g., erythromycin, diltiazem, verapamil)
- PDE5 inhibitors (e.g., sildenafil, tadalafil, vardenafil) - increased risk of symptomatic orthostatic hypotension
Moderate Interactions
- Antihypertensives (e.g., calcium channel blockers, ACE inhibitors, diuretics) - increased risk of hypotension
- P-glycoprotein inhibitors (e.g., cyclosporine)
Minor Interactions
- Digoxin (minor increase in digoxin levels)
Monitoring
Baseline Monitoring
Blood Pressure (sitting and standing)
Rationale: To assess for baseline orthostatic hypotension risk and guide treatment initiation.
Timing: Prior to initiation
Renal Function (CrCl)
Rationale: To determine appropriate dosing, as silodosin is renally excreted and dose adjustment is needed for moderate impairment, and contraindicated in severe.
Timing: Prior to initiation
Hepatic Function (Child-Pugh score)
Rationale: To assess for severe hepatic impairment, where silodosin is not recommended.
Timing: Prior to initiation
Prostate Specific Antigen (PSA)
Rationale: To rule out prostate cancer, as BPH symptoms can mimic prostate cancer.
Timing: Prior to initiation and periodically thereafter as per guidelines
Routine Monitoring
Blood Pressure (sitting and standing)
Frequency: Periodically, especially during initial therapy or dose changes
Target: Maintain within patient's normal range, monitor for symptomatic hypotension
Action Threshold: Symptomatic orthostatic hypotension (dizziness, lightheadedness, syncope); significant drop in BP (e.g., >20 mmHg systolic or >10 mmHg diastolic upon standing)
BPH Symptom Score (e.g., IPSS)
Frequency: Every 3-6 months or as clinically indicated
Target: Improvement in symptoms
Action Threshold: Lack of symptom improvement or worsening symptoms
Symptom Monitoring
- Dizziness
- Lightheadedness
- Syncope (fainting)
- Orthostatic hypotension
- Retrograde ejaculation (reduced or absent semen during orgasm)
- Diarrhea
- Nasal congestion
- Headache
- Insomnia
Special Patient Groups
Pregnancy
Silodosin is indicated for use in men only. Not applicable for use in women.
Trimester-Specific Risks:
First Trimester:
Not applicable
Second Trimester:
Not applicable
Third Trimester:
Not applicable
Lactation
Silodosin is indicated for use in men only. Not applicable for use in women.
Infant Risk:
Not applicable
Pediatric Use
Safety and effectiveness 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. Dose adjustment based solely on age is not required, but careful monitoring for orthostatic symptoms is recommended.
Clinical Information
Clinical Pearls
- Silodosin is highly selective for alpha-1A receptors, which may lead 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 (occurring in up to 28% of patients), which should be discussed with patients prior to initiation.
- Always take silodosin with a meal to optimize absorption and reduce the risk of orthostatic symptoms.
- Contraindicated with strong CYP3A4 inhibitors due to significantly increased silodosin exposure and risk of adverse effects.
- Patients undergoing cataract surgery should inform their ophthalmologist about silodosin use due to the risk of Intraoperative Floppy Iris Syndrome (IFIS).
Alternative Therapies
- Other alpha-1 adrenergic antagonists (e.g., tamsulosin, alfuzosin, doxazosin, prazosin)
- 5-alpha reductase inhibitors (e.g., finasteride, dutasteride) - for larger prostates, slower onset of action
- PDE5 inhibitors (e.g., tadalafil - for BPH and ED)
- Combination therapy (alpha-blocker + 5-alpha reductase inhibitor)
- Minimally invasive procedures (e.g., UroLift, Rezum)
- Surgical interventions (e.g., TURP)
Cost & Coverage
Average Cost:
$150 - $300 per 30 capsules
Generic Available:
Yes
Insurance Coverage:
Tier 2 or Tier 3 (for brand, generic often Tier 1)
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. 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 it's a good idea to check with your pharmacist. If you have any questions or concerns about this medication, don't hesitate to discuss them with your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide detailed information about the overdose, including the medication taken, the amount, and the time it occurred.