finasteride/tamsulosin

Action and Spectrum

Actions and Spectrum: 

Action: 

finasteride is a medication that inhibits the activity of the enzyme 5-alpha-reductase. This enzyme generally converts testosterone into dihydrotestosterone (DHT), a hormone that plays a role in prostate gland growth. By blocking this conversion, finasteride reduces the levels of DHT in the prostate tissue.  

tamsulosin is an alpha-1 adrenergic receptor antagonist. It typically works by relaxing the smooth muscles in the prostate and the bladder neck. Doing so helps to improve urine flow and relieve symptoms associated with BPH, such as urinary hesitancy, urgency, frequency, and weak stream. tamsulosin does not affect the size of the prostate but helps alleviate the obstruction caused by an enlarged prostate. 

Spectrum: 

Benign Prostatic Hyperplasia (BPH): finasteride is commonly prescribed to men with BPH to reduce the size of the prostate gland, relieve urinary symptoms, and potentially prevent complications such as urinary retention. 

Male Pattern Baldness: In lower doses, finasteride is also used to treat male pattern baldness by preventing hair loss and promoting hair regrowth. 

Benign Prostatic Hyperplasia (BPH): tamsulosin is primarily prescribed to men with BPH to alleviate the bothersome urinary symptoms associated with the condition. It does not treat the underlying cause (prostate enlargement) but provides symptomatic relief. 

Drug Interaction

Adverse Reaction

Frequency not defined 

Breast tenderness 

Impotence 

Increased libido 

Hypersensitivity reactions 

Black Box Warning

Black Box Warning: 

None 

Contraindication / Caution

Contraindication/Caution: 

Contraindication 

finasteride: 

• Hypersensitivity: Individuals with a known hypersensitivity or allergy to finasteride or its components should not take the medication. 
• Pregnancy and Women of Childbearing Potential: finasteride is not intended for use in women, particularly pregnant women or women who may become pregnant. finasteride can cause harm to a developing male fetus if a pregnant woman is exposed to it. 
• Pediatric Use: finasteride is not typically used in pediatric patients, as its safety and efficacy in children have not been established. 
• Severe Liver Disease: Individuals with severe liver disease may have impaired metabolism and clearance of finasteride, which can affect its safety and effectiveness. It should be used with caution or avoided in this population. 

tamsulosin: 

• Hypersensitivity: Like finasteride, individuals with known hypersensitivity or allergy to tamsulosin or related medications should not take tamsulosin. 
• Severe Liver Disease: tamsulosin should be used cautiously in individuals with severe liver disease, as its clearance may be affected. Dose adjustments may be necessary. 
• Severe Kidney Disease: In patients with severe kidney disease (end-stage renal disease requiring dialysis), tamsulosin may need to be adjusted, and careful monitoring is essential. 
• Orthostatic Hypotension: tamsulosin may cause a drop in blood pressure, leading to orthostatic hypotension (a sudden decrease in blood pressure from lying down to standing). It should be used cautiously in individuals at risk of severe orthostatic hypotension, such as those with a history of syncope or hypotension. 
• Concomitant Use with Alpha-Blockers: tamsulosin is an alpha-1 adrenergic receptor antagonist. It should not be used concurrently with other alpha-blockers, as this can increase the risk of side effects, including severe hypotension. 
• Intraoperative Floppy Iris Syndrome (IFIS): tamsulosin has been associated with IFIS during cataract surgery. Patients considering cataract surgery should inform their eye surgeon if they are taking or have taken tamsulosin, as special precautions may be needed. 

Caution 

finasteride: 

• Pregnancy and Women: As mentioned before, finasteride should not be handled by pregnant women or women of childbearing potential because of the risk of harm to a male fetus. If a woman does come into contact with the medication, she should wash her hands thoroughly. 
• Prostate-Specific Antigen (PSA) Test: finasteride can lower PSA levels, which may affect the interpretation of PSA test results when screening for prostate cancer. Healthcare providers should be informed if a PSA test is planned while taking finasteride. 
• Sexual Side Effects: Some individuals may experience sexual side effects like the decreased libido, erectile dysfunction, or reduced ejaculate volume while taking finasteride. These side effects should be discussed with a healthcare provider if they occur. 
• Psychological Effects: Rarely, finasteride has been associated with psychological side effects like depression or anxiety. If these symptoms occur, it’s essential to seek medical advice promptly. 
• Concomitant Medications: Potential interactions and side effects should be considered when taking other medications concurrently with finasteride.  

tamsulosin: 

• Orthostatic Hypotension: tamsulosin may cause a drop in BP, especially when standing up from a sitting or lying position. This may lead to dizziness or fainting. Caution should be exercised, especially in older people and those prone to orthostatic hypotension. 
• Cataract Surgery: During cataract surgery, tamsulosin has been associated with Intraoperative Floppy Iris Syndrome (IFIS). Inform your eye surgeon if you are taking tamsulosin and are planning to undergo cataract surgery. 
• Other Alpha-Blockers: Avoid taking multiple alpha-blockers simultaneously, as this can increase the risk of side effects, including severe hypotension. 
• Severe Liver or Kidney Disease: Dose adjustments may be necessary in individuals with severe liver or kidney disease. Close monitoring is essential in these cases. 
• Preexisting Low Blood Pressure: tamsulosin may lower your blood pressure if you already have low blood pressure. Discuss this with your healthcare provider. 
• Medication Interactions: tamsulosin may interact with other medications, such as blood pressure-lowering drugs or medications for erectile dysfunction.

Pregnancy / Lactation

Pregnancy consideration:  

US FDA pregnancy category: Not assigned. 

Lactation:   

Excreted into human milk: Not known. 

Pregnancy category: 

• Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester. 
• <b>Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women. 
• Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    
• Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.    
• Category X: Drugs listed in this category outweigh the risks over benefits. Hence, these categories of drugs need to be avoided by pregnant women.    
• Category N: There is no data available for the drug under this category. 

Pharmacology

Pharmacology: 

finasteride is a 5-alpha-reductase inhibitor that generally blocks the conversion of testosterone to the dihydrotestosterone, a hormone involved in the growth of the prostate gland. By reducing DHT levels, finasteride slows prostate enlargement, typically leading to symptom improvement in conditions like benign prostatic hyperplasia (BPH) and androgenetic alopecia. Conversely, tamsulosin is an alpha-1 adrenergic receptor antagonist that relaxes smooth muscles in the prostate and bladder neck.

This relaxation enhances urine flow and alleviates urinary symptoms associated with BPH. When prescribed, the combination of these medications addresses both the underlying cause of prostate enlargement and the symptomatic relief of urinary issues, offering a comprehensive approach to managing BPH. Their pharmacokinetics include oral administration, sound absorption, and elimination through urine and feces, with half-lives of approximately 6 hours for finasteride and 9-13 hours for tamsulosin. 

Pharmacodynamics: 

Mechanism of action: finasteride is a 5-alpha-reductase inhibitor. It generally works by inhibiting the activity of the enzyme 5-alpha-reductase, which is generally responsible for converting testosterone into dihydrotestosterone (DHT) in specific tissues, including the prostate gland. DHT is a more potent androgen hormone than testosterone and plays a role in stimulating the growth of the prostate gland. By reducing the levels of DHT in the prostate, finasteride slows down the growth of the prostate tissue and can shrink the size of the prostate over time. 

tamsulosin is an alpha-1 adrenergic receptor antagonist. These receptors regulate the tone of smooth muscles in these areas. This relaxation leads to improved urinary flow and reduced symptoms associated with BPH, such as urinary hesitancy, urgency, frequency, and weak urine stream. When used together in treating BPH, finasteride and tamsulosin complement each other’s actions. finasteride addresses the underlying cause of prostate enlargement by reducing DHT levels and slowing prostate growth.  

Pharmacokinetics: 

Absorption: finasteride is well-absorbed after oral administration. It is absorbed typically in the upper gastrointestinal tract, and food can affect its absorption, leading to slightly increased bioavailability when taken with a meal. 

tamsulosin is rapidly absorbed after oral administration, and its absorption is affected by food. Taking tamsulosin approximately 30 minutes after the same meal each day is recommended to enhance its bioavailability. 

Distribution: finasteride is extensively distributed throughout the body, including into the prostate gland, which exerts its therapeutic effects. It has a high affinity for binding to plasma proteins. 

tamsulosin is extensively distributed in the body, with a high affinity for alpha-1 adrenergic receptors in the prostate, bladder, and blood vessels. It has limited blood-brain barrier penetration, which minimizes central nervous system effects. 

Metabolism: finasteride undergoes extensive metabolism in the liver, primarily through the CYP3A4 enzyme. It is converted into metabolites that are less potent than the parent compound. One of the metabolites is eliminated through the urine, while the others are eliminated through feces. 

tamsulosin undergoes minimal hepatic metabolism, and most of the drug remains unchanged. It is primarily metabolized by the liver enzyme CYP3A4. Genetic polymorphisms in CYP2D6 can also affect its metabolism in some individuals. 

Elimination and Excretion 

The elimination half-life of finasteride is approximately 6 hours. Most of the drug and its metabolites are typically excreted in the urine, while a smaller fraction is eliminated in the feces. 

tamsulosin has an elimination half-life of approximately 9-13 hours. Most of the drug and its metabolites are typically excreted in the urine, with a smaller fraction eliminated in the feces. 

Adminstartion

Administration: 

The administration of finasteride and tamsulosin involves taking these medications as directed by the healthcare provider.  

finasteride: 

Dosage: finasteride is typically available in tablet form. The recommended dose for benign prostatic hyperplasia (BPH) is 5 milligrams (mg) once daily. 

Timing: finasteride can be taken with or without food. It’s essential to take it simultaneously daily to maintain consistent drug levels. 

Duration: The duration of finasteride treatment may vary depending on the condition being treated. For BPH, it often takes a long time to manage symptoms. For male pattern baldness, treatment may continue as long as desired results are maintained. 

Follow Healthcare Provider’s Instructions: Always follow your healthcare provider’s instructions regarding the specific dose and duration of finasteride treatment. 

Handling: If you are handling finasteride tablets and are a woman of childbearing potential, use caution and wash your hands thoroughly after contact with the medication to avoid potential exposure to a developing male fetus. 

Regular Check-ups: Your healthcare provider may schedule regular check-ups to monitor the effectiveness of the medication and assess for any potential side effects. 

Administration of tamsulosin: 

Dosage: tamsulosin is typically available in capsule form. The most common dose for benign prostatic hyperplasia (BPH) is 0.4 milligrams (mg) once daily. 

Timing: tamsulosin should be taken approximately 30 minutes after the same meal daily, as food can affect absorption. Taking it consistently with food can help reduce the risk of dizziness or lightheadedness. 

Duration: tamsulosin is often prescribed for long-term use to manage BPH symptoms. Follow your healthcare provider’s guidance regarding the duration of treatment. 

Avoid Crushing or Chewing: Swallow tamsulosin capsules whole; do not crush or chew them. 

Orthostatic Hypotension: Be cautious when standing up from a sitting or lying position, especially when taking tamsulosin, as it can cause orthostatic hypotension (a drop in blood pressure upon standing). 

Regular Check-ups: Your healthcare provider may schedule regular check-ups to monitor your response to tamsulosin and assess any side effects. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: finasteride/tamsulosin 

Why do we use finasteride/tamsulosin? 

The combination of finasteride and tamsulosin is sometimes used in treating men with benign prostatic hyperplasia (BPH), a non-cancerous prostate gland enlargement. BPH can lead to urinary symptoms such as urinary frequency, urgency, weak urine stream, and difficulty starting or stopping urination. The combination of finasteride and tamsulosin can offer a more comprehensive approach to managing BPH by addressing different aspects of the condition.  

Management of BPH Symptoms: The combination of finasteride and tamsulosin is often prescribed to help manage the symptoms of BPH more effectively than either medication alone. 

Relief of Urinary Symptoms: tamsulosin is an alpha-1 adrenergic receptor antagonist that relaxes the smooth muscles in the prostate and bladder neck. This relaxation helps improve urine flow and reduce urinary symptoms associated with BPH, such as hesitancy, urgency, and weak stream. 

Combining Mechanisms of Action: The combination of finasteride and tamsulosin takes advantage of both medications’ different mechanisms of action. finasteride addresses the underlying issue of prostate enlargement, while tamsulosin provides symptomatic relief by relaxing smooth muscles. 

Potential Synergy: Some studies suggest combining finasteride and tamsulosin may provide better symptom relief and improved quality of life for men with moderate to severe BPH compared to using either medication alone.