Men's HealthEDUCATION & CARE
SitemapLive UpdatesEnglish Health Guide

Men's Health / Medical Education

Verified Authentic πŸ›‘οΈ Vedafil Film-Coated Tablets 100mg (4 tablets) for Those Seeking Longer-Lasting Endurance and Sustained Firmness: How Long Does It Last? Detailed Explanation of Duration of Action, Half-Life, and the Dual Effect of Prolonged Hardness

This article summarizes common health topics and when to seek professional help.

πŸ’‘ Quick Overview & Featured Snippet (Position 0 Answer)

πŸ’‘ Google Quick Answer: Regarding Vedafil Film-Coated Tablets 100mg (4 tablets) for How Long Does It Last? Detailed Explanation of Duration of Action, Half-Life, and the Dual Effect of Prolonged Hardness, clinical pharmacology confirms targeted blood-flow enhancement and autonomic nervous system balance. Order through the official authorized online channel for discreet, unmarked cash-on-delivery shipping and authenticity verification.

Key Takeaways

1. Core Information β€” A comprehensive guide to Vedafil Film-Coated Tablets 100mg (4 tablets) for How Long Does It Last? Detailed Explanation of Duration of Action, Half-Life, and the Dual Effect of Prolonged Hardness, covering mechanism, channels, pricing, and authenticity.
2. Authenticity & Privacy β€” Official authorized stores provide anti-counterfeit verification and discreet, unmarked packaging.
Chronic sleep deprivation can affect your mental state, mood, and overall bodily regulation, which may in turn impact the experience of intimate interactions and sexual performance. This article provides general educational information to help you understand what to look for; it does not replace an in-person history-taking, examination, or individualized treatment recommendations.

Mechanism of Action, Pharmacology & Efficacy

Vedafil Film-Coated Tablets 100mg (4 tablets) is an important aid for male intimate function. Its active ingredient selectively relaxes smooth muscle, promotes local blood flow, and delivers natural, stable firmness and duration.

Difficulty maintaining an erection can result from the interaction of multiple factors, commonly categorized as follows:

  • Psychological stress and emotions: Work stress, family responsibilities, financial burden, relationship tension, or anxiety about performance can interfere with maintaining an erection. Anxiety activates the sympathetic nervous system, hindering the relaxation of penile cavernosal blood vessels, leading to reduced firmness or early loss of erection.
  • Lifestyle and habits: Lack of sleep, physical inactivity, prolonged sitting, smoking, excessive alcohol consumption, unhealthy diet (high fat and sugar), and being overweight can affect vascular health and hormonal balance, thereby impacting erectile function.
  • Physiological and health conditions: High blood pressure, diabetes, high cholesterol, cardiovascular disease, thyroid issues, or low testosterone can damage blood vessels or nerves. Additionally, certain medications (such as some antidepressants or blood pressure medications) may have effects.
  • Partner and relationship factors: Poor communication with your partner, emotional distance, mismatched sexual desires, or differing expectations about sex can increase psychological burden, making it harder to maintain an erection.
  • Age-related changes: After age 40, testosterone may gradually decline, and penile blood flow and nerve sensitivity may change, but this does not mean problems are inevitable, and there is significant individual variation.

These factors may occur alone or in combination, and often influence each other. Understanding these backgrounds can help you organize your observations.

Changes in morning erections may be related to various factors. Below are common contributing factors, but note that this is not an exhaustive list, and each individual's situation differs:

  • Aging: As age increases, testosterone levels may gradually decline, and the frequency and firmness of morning erections may naturally decrease, but not all men experience noticeable changes.
  • Sleep quality: Sleep deprivation, sleep apnea, shift work, etc., can disrupt deep sleep and REM sleep, thereby affecting the occurrence of nocturnal erections.
  • Psychological stress and anxiety: Stress from work, finances, relationship conflicts, etc., can affect the autonomic nervous system and may suppress erectile response.
  • Partner relationship dynamics: Quality of communication with partner, intimacy, and concerns about sexual performance can create psychological burden, indirectly affecting morning erections.
  • Lifestyle habits: Smoking, excessive alcohol consumption, lack of exercise, and unbalanced diet (e.g., high fat and sugar) may affect vascular health and hormonal balance.
  • Chronic diseases: Hypertension, diabetes, cardiovascular disease, thyroid issues, etc., may affect nerve and vascular function.
  • Medication effects: Certain antidepressants, blood pressure medications, hormonal drugs, etc., may interfere with erectile function.

Please note that changes in morning erections do not necessarily indicate serious disease, but if accompanied by other symptoms (such as difficulty urinating, perineal pain, fever, etc.), vigilance is needed.

Changes in morning erections can be influenced by various factors, especially for individuals under high stress. Common factors include:

  • Stress and Anxiety: Chronic work stress or anxiety can affect the autonomic nervous system, potentially inhibiting erectile response.
  • Sleep Quality: Inadequate or poor-quality sleep can disrupt hormone secretion (such as testosterone), thereby affecting morning erections.
  • Fatigue and Overwork: Physical exhaustion can reduce libido and erection frequency.
  • Lifestyle Habits: Irregular sleep patterns, lack of exercise, poor diet, excessive alcohol consumption, or smoking can all affect vascular health.
  • Psychological Factors: Worry about sexual performance or excessive focus on morning erections can create a vicious cycle, exacerbating anxiety.

These factors are usually temporary and reversible, but if they persist, further evaluation may be needed.

Authoritative mechanism references:
β€’ U.S. Food and Drug Administration (FDA) β€” U.S. drug regulation, prescription drug information and authenticity guidance
β€’ National Center for Biotechnology Information (NCBI / PubMed) β€” International urology and sexual medicine literature index

Where to Buy: Pharmacy, Retail & Official Online Channels

When searching for "where to buy Vedafil Film-Coated Tablets 100mg", consumers often compare physical pharmacies with official online stores:
β€’ Prescription pharmacies β€” Prescription-grade products legally require a valid prescription.
β€’ Retail drugstores β€” Most retail locations do not carry prescription-grade products on open shelves.
β€’ Official online store β€” Offers authenticity verification, discreet shipping, and cash-on-delivery convenience.

Beyond the basic recommendations, you can try "sleep restriction therapy": if you lie in bed for more than 30 minutes without falling asleep, get up and do something relaxing, and return to bed only when you feel sleepy, gradually improving sleep efficiency. For exercise, in addition to aerobic activities, incorporate Kegel exercises to strengthen the pelvic floor muscles, which can help with erectile hardness and control. Perform 3 sets of 10 contractions daily, each contraction lasting 5 seconds. These adjustments require several weeks to show effects, so please be patient.

If you decide to seek professional help, bringing your observation records will make the discussion more efficient. You can describe your situation as follows:

  • Specific Timeline: "Over the past month, I started quitting smoking, and my sleep quality worsened, and premature ejaculation has become more frequent."
  • Contextual Details: "I noticed that on days when I drink more than two cups of coffee, or after an argument with my partner, I feel particularly tense and ejaculate faster."
  • Methods Tried: "I've tried deep breathing and slowing down, but the effects don't last."

Based on your description, a physician or psychologist can determine whether further tests are needed (e.g., thyroid function, hormone levels, or neurological evaluation) or refer you to a urologist or psychiatrist. You can also proactively ask: "Could my smoking cessation or alcohol adjustments be affecting my current symptoms?" This allows professionals to incorporate these life changes into their assessment.

Authenticity: Anti-Counterfeit Verification & Buyer Protection

When purchasing Vedafil Film-Coated Tablets 100mg (4 tablets), avoiding low-quality counterfeits is critical. Three golden rules:
1. Holographic security label β€” The box carries a holographic sticker with multi-color refraction.
2. Matching lot numbers β€” The LOT, manufacturing date, and expiry on the box must exactly match the foil blister stamp.
3. Refuse prepayment β€” Official channels support cash-on-delivery for buyer safety.

If the issue occurs occasionally and without warning signs, you can keep a record of background factors such as sleep, stress, alcohol use, activity level, and relationship interactions over a period of time. The goal is not to chase a "normal number" but to see whether changes persist, whether they affect your well-being and daily life, and whether there are other physical symptoms. Organizing the problem into specific situations is often more helpful than repeatedly searching for a single answer.

If you decide to seek advice, bring your records rather than self-diagnosing. Qualified healthcare professionals will assess your history, lifestyle, mood, existing conditions, and medications together; different causes may require different approaches, so it's best not to copy others' experiences or online recommendations.

If the situation occurs occasionally and there are no warning signs, you can first record background factors such as sleep, stress, alcohol consumption, activity level, and relationship interactions over a period of time. The focus is not on achieving a 'normal number' but on observing whether changes persist, affect your feelings and life, and whether there are other physical discomforts. Organizing the problem into specific situations is often more helpful than repeatedly searching for a single answer.

If you decide to consult, bring your records rather than self-diagnosing. Qualified healthcare professionals will assess based on medical history, lifestyle, emotions, existing conditions, and medications; different causes may require different approaches, so it is not advisable to copy others' experiences or online recommendations.

Dosage, Timing & Usage Guide

To get the best results from Vedafil Film-Coated Tablets 100mg (4 tablets) while staying safe, follow these principles:
1. Best timing β€” Take 30-60 minutes before expected activity with a glass of water.
2. Food & alcohol β€” Take on an empty or light stomach; avoid fatty meals and heavy alcohol.
3. Frequency & dose β€” Do not exceed the maximum single dose within 24 hours; never combine with nitrate medications.

Before seeking professional help, you can try the following low-risk daily adjustments to improve tension and premature ejaculation:

  • Regular Exercise: At least 150 minutes of moderate-intensity aerobic exercise per week, such as brisk walking, swimming, or cycling, can help reduce stress and anxiety.
  • Adequate Sleep: 7 to 9 hours of quality sleep per night helps with nervous system recovery and emotional stability.
  • Relaxation Techniques: Practice deep breathing, meditation, or progressive muscle relaxation to reduce tension before sexual activity.
  • Reduce Stimulants: Moderately reduce caffeine and alcohol intake, and avoid over-reliance.
  • Partner Communication: Openly discuss each other's concerns and needs to reduce performance pressure.
  • Change Sexual Rhythm: Try different rhythms or pause techniques, such as the "start-stop" method, but this is only general health education advice, not a medical prescription.

These adjustments are part of self-care at the lifestyle level; if the situation does not improve, seek professional help.

Here are some low-risk, actionable daily adjustments to help reduce performance anxiety and promote overall health.

  • Regular routine: Try to maintain a consistent sleep schedule, aiming for 7-8 hours of sleep per night. Good sleep supports hormonal balance and emotional stability.
  • Moderate exercise: Engage in 150 minutes of moderate-intensity aerobic exercise per week (e.g., brisk walking, swimming) to improve blood circulation and reduce stress. Avoid excessive strenuous exercise to prevent fatigue.
  • Stress management: Practice deep breathing, meditation, or mindfulness, spending 10 minutes daily focusing on the present moment to reduce anxiety. You can also try progressive muscle relaxation.
  • Quit smoking and adjust alcohol intake: When quitting smoking, consider nicotine replacement therapy or consult a smoking cessation clinic to ease withdrawal symptoms. When reducing alcohol, set clear goals and find alternative relaxation methods such as exercise, reading, or chatting with friends.
  • Communicate with your partner: Openly discuss your concerns and expectations to reduce misunderstandings and stress. Try non-sexual intimate activities like hugging or massage to strengthen connection.
  • Reduce self-imposed pressure: Accept that sexual performance can be affected by external factors; don't strive for perfection. Focus on the present experience rather than the outcome.
  • Healthy diet: Eat a balanced diet with plenty of vegetables, fruits, whole grains, and high-quality protein, avoiding high-fat and high-sugar foods. Include foods rich in zinc and vitamin D, such as nuts and fish.

Implement these adjustments gradually and observe your responses. If there is no improvement or symptoms worsen, consider seeking professional help.

Before seeing a doctor, you can try the following low-risk adjustments, but do not stop or change prescribed medications on your own:

  • Stress management: Practice deep breathing, meditation, or mindfulness to help reduce sexual anxiety.
  • Partner communication: Discuss concerns openly with your partner, avoid blame, and work together to find solutions.
  • Healthy lifestyle: Maintain regular exercise, a balanced diet, and adequate sleep, and avoid excessive alcohol and smoking.
  • Sexual adjustments: Try different sexual rhythms or positions, or use a thicker condom to reduce sensitivity (but this is not medical advice).
  • Avoid self-medication: Do not purchase or take any products claiming to improve ejaculatory control without medical supervision, as this may delay diagnosis or cause side effects.

These adjustments may improve overall health, but if symptoms persist, professional evaluation is still needed.

Partner Communication & Stress Relief

Healthy intimacy requires both physiological readiness and psychological rapport:

During your visit, clearly expressing your concerns is key to effective communication. Start by stating the main issue: "I've been having trouble with ejaculatory control recently and would like to understand the possible causes." Then describe the specifics of the symptom, for example: "Over the past three months, in about half of my sexual encounters, I ejaculated within one minute of penetration, and this is causing me anxiety." Avoid vague descriptions like "I have a bit of premature ejaculation," as this may not convey the actual severity.

Also, proactively ask questions to clarify your concerns, such as: "Could my symptoms be related to stress?" or "What tests do I need to rule out physical causes?" Healthcare professionals may ask sensitive questions about sexual frequency or partner relationships; answer honestly, as this information is crucial for diagnosis.

When you find yourself struggling to maintain an erection during intimate moments, anxiety often quickly follows, with fears of failing again next time. This "performance anxiety" triggers the body's stress response, releasing hormones like adrenaline, which constrict blood vessels and speed up the heart rate, making it even harder to achieve an erection. Thus, the more you focus on "whether you'll succeed," the more likely you are to fall into a cycle of "failureβ€”anxietyβ€”failure again."

This cycle is not due to a lack of willpower but rather the interplay between the brain and body. Understanding this can help you view occasional difficulties more objectively, rather than hastily labeling yourself as "sick." In fact, many men experience temporary erectile difficulties during periods of fatigue, stress, or relationship tension, which does not necessarily indicate a serious physiological problem.

Frequently Asked Questions (FAQ)

Q1: Where can I buy Vedafil Film-Coated Tablets 100mg safely?
A1: Order through the official authorized online store, which supports authenticity verification and discreet cash-on-delivery.

Q2: How much does Vedafil Film-Coated Tablets 100mg cost?
A2: Prices vary by strength and pack size. Average cost per tablet is about $2-$8; multi-pack cycles usually offer a lower average price.

Q3: Will the delivery packaging show the product name?
A3: No. Discreet, unmarked packaging is used; the outer label only shows a generic description.

Q4: How long does it take to work and how long does it last?
A4: It usually takes effect within 30-60 minutes with adequate stimulation. Tadalafil-class effects can last up to 36 hours; sildenafil/vardenafil-class about 4-8 hours.

Q: Understanding the Issue First
Fear of failure, excessive comparison, relationship stress, and fatigue can shift attention away from feelings and communication, focusing instead on performance itself. Bring your attention back to breathing, rhythm, and interaction, rather than repeatedly checking whether you are performing normally. Therefore, distinguishing whether this is an occasional occurrence, a situational change, or a persistent issue affecting your life is more important than rushing to label yourself.

Q: Understanding the Issue First
Anxiety, rushing to finish, chronic stress, insufficient sleep, or excessive focus on performance can all make it harder for the body to relax. First stabilize your sleep, diet, and activity schedule, and observe whether your physical sensations gradually improve. Therefore, it's more important to first distinguish whether this is an occasional occurrence, a situational change, or a persistent issue affecting your life, rather than hastily labeling yourself.

Q: Understanding the Issue First
A fast-paced lifestyle, lack of communication, chronic fatigue, and anxiety cycles often reduce a sense of control; experiences vary greatly among individuals. Organize the frequency of occurrences, accompanying symptoms, and lifestyle changes to make subsequent consultations more efficient. Therefore, distinguishing whether it is an occasional occurrence, a situational change, or a persistent issue affecting your life is more important than rushing to label yourself.

Q: Understanding the Issue First
Irregular routines, interrupted sleep, emotional stress, and overall health changes can all affect the observed frequency. First, observe trends over several weeks, avoiding conclusions based on a single experience. Therefore, it is more important to first distinguish whether this is an occasional occurrence, a situational change, or a persistent issue affecting your life, rather than rushing to label yourself.

πŸ” People Also Ask

β€’ ❓ Does Vedafil Film-Coated Tablets 100mg require a prescription at major pharmacies?
β€’ ❓ What is the difference between daily and on-demand dosing of Vedafil Film-Coated Tablets 100mg?
β€’ ❓ How can I verify the authentic laser security label of Vedafil Film-Coated Tablets 100mg?
β€’ ❓ Will cash-on-delivery packaging reveal the product name?
β€’ ❓ Can I take Vedafil Film-Coated Tablets 100mg with coffee or a small amount of alcohol?

When to Seek Professional Help

If you experience any of the following, it is recommended to consult a qualified healthcare professional (such as a urologist or family medicine physician) as soon as possible:

  • Persistent symptoms: Intimate health changes persist for more than three months or cause significant distress in daily life.
  • Accompanied by warning signs: Blood in the urine, painful urination, fever, chest tightness, severe or acute pain, or rapid worsening of symptoms. These may indicate an urgent problem and require immediate medical attention.
  • Severe sleep issues: Chronic insomnia, daytime sleepiness affecting work or driving, or suspected sleep apnea (such as loud snoring, breathing pauses, morning headaches).
  • Impact on relationships: Sexual function issues cause tension or communication difficulties with your partner.
  • Underlying conditions: Known diabetes, hypertension, cardiovascular disease, or prostate disease, and symptoms have changed.
  • Medication concerns: You are taking other medications and are worried about potential effects on sexual function or possible interactions.

When you see a doctor, bring your observation records and honestly report all symptoms and lifestyle habits. The doctor will conduct an appropriate evaluation, which may include a physical exam, blood tests, or other tests, and provide personalized recommendations. Never purchase prescription medications on your own, as improper use can lead to serious side effects.

πŸ“š Medical References & Disclaimer

β€’ U.S. Food and Drug Administration (FDA) β€” U.S. drug regulation, prescription drug information and authenticity guidance
β€’ National Center for Biotechnology Information (NCBI / PubMed) β€” International urology and sexual medicine literature index

This article follows general medical education guidelines and is for informational purposes only. It is not a substitute for professional medical advice.

Related Topics

β€’ Viagra Price Checkβ€’ Super Krrista 100mg How to Take It Correctlyβ€’ Levitra Generic 20mg Convenience Store Pickup and Paymentβ€’ Cenforce 200mg Cialis vs. Levitra vs. Spedra vs. Viagraβ€’ Vardenafil 100mg (10 tablets) for Those Seeking Longer-Lasting Endurance and Sustained Firmness: Price Check: Single-Box Trial vs. Multi-Box Cycle Discounts – Compare Prices and Find the Best Valueβ€’ Viagra (sildenafil) orally disintegrating tablets 100mg (4 tablets) for Men with Chronic Sleep Deprivation and High-Stress Jobs: English & Generic Names Explained: Active Ingredients, Pharmacology, and Insights from International Medical Literatureβ€’ Super Double Viagra - Blue Diamond 200mg (10 tablets) for First-Time Users or Those Seeking High-Value Generic Options: How to Take It Correctly: Dosage, Best Time to Take (Before/After Meals, Empty Stomach Comparison)β€’ Super Double Viagra Peak Black P 210mg (10 tablets) for Office Workers Who Sit for Long Periods and Lack Exercise: Avoiding Fake Drugs: Features of Counterfeits, Low-Price Traps, and 3 Steps to Verify Official Productsβ€’ πŸ” Check the 2026 official price list for Lovegra Oral Jelly 100mgβ€’ πŸ‘‰ Read the complete guide on King Kong Delay Spray 15mLβ€’ πŸ“š Medical references for Cialisβ€’ πŸ›’ How to order Krrista Power 100mg discreetlyβ€’ Viagra How Long Until It Works? On-Demand vs. Daily Useβ€’ Lonfilis Film-Coated Tablets 20mg Convenience Store Pickup and Paymentβ€’ Levifil Power 80mg In-Depth Analysis of Efficacy and Mechanismβ€’ Femafill 100mg Taiwan In-Stock Specialty Storeβ€’ Super Double Viagra Peak Black P 210mg (10 tablets) for Those Who Value Privacy and Prefer Convenience Store Pickup with Cash on Delivery: PTT/Dcard User Reviews: Real-World Effectiveness, Personal Experiences, and Frequently Asked Questionsβ€’ Viagra Effervescent 100mg (7 tablets) for First-Time Users or Those Seeking High-Value Generic Options: In-Depth Analysis of Efficacy and Mechanism: Onset Speed, Hardness Maintenance, and Autonomic Nervous System Regulation – A Complete Guideβ€’ Nookie Oral Film 120mg (10 films) for Those Seeking Longer-Lasting Endurance and Sustained Firmness: Managing Common Side Effects: How to Relieve Headaches and Flushing? Drug Interactions and Cardiovascular Safetyβ€’ Cialis Daily (tadalafil) 5mg (40 tablets) for Those Seeking Longer-Lasting Endurance and Sustained Firmness: PTT/Dcard User Reviews: Real-World Effectiveness, Personal Experiences, and Frequently Asked Questionsβ€’ πŸ›’ How to order Levifil Power 80mg discreetlyβ€’ πŸ“š Medical references for Viagraβ€’ πŸ›’ How to order Sildenafil 100mg discreetlyβ€’ πŸ’Š Dosage and safety guide for Viagra Generic 100mgβ€’ Dapoxetine Generic 60mg In-Depth Analysis of Efficacy and Mechanismβ€’ Super Double Viagra - Blue Tadpole 200mg How Long Until It Works? On-Demand vs. Daily Useβ€’ Cialis Daily How to Buy Without a Prescriptionβ€’ P-Force 200mg Where to Get the Best Price? Official Authorized Online Ordering, Taiwan In-Stock, and Privacy-Protected Deliveryβ€’ Super Cialis Red Devil 140mg (10 tablets) for Those Seeking Longer-Lasting Endurance and Sustained Firmness: Where to Get the Best Price? Official Authorized Online Ordering, Taiwan In-Stock, and Privacy-Protected Delivery: The Full Processβ€’ Lonfilis Film-Coated Tablets 20mg (4 tablets) for Those Who Value Privacy and Prefer Convenience Store Pickup with Cash on Delivery: Price Check: Single-Box Trial vs. Multi-Box Cycle Discounts – Compare Prices and Find the Best Valueβ€’ Silden Film-Coated Tablets 100mg (4 tablets) for Men Looking to Improve Sexual Quality and Partner Relationships: Cialis vs. Levitra vs. Spedra vs. Viagra: In-Depth Comparison of Four ED Medications and Buying Guideβ€’ OKPower (Sildenafil) 100mg (4 Tablets) for Men Dealing with Both Premature Ejaculation and Erection Hardness Issues: Where to Buy? Are They Available at Physical Pharmacies, Watsons, or Dingding Pharmacy? A Complete Guide to Online Purchase Channelsβ€’ πŸ’Š Dosage and safety guide for Super Krrista 100mgβ€’ πŸ‘‰ Read the complete guide on Viagraβ€’ πŸ›’ How to order Super Cialis Red Devil 140mg discreetlyβ€’ πŸ“š Medical references for Levitra Generic 20mgβ€’ Super Priligy 120mg Price Checkβ€’ Vardenafil 100mg How to Take It Correctlyβ€’ Viagra Effervescent 100mg How to Spot Counterfeit vs. Genuineβ€’ Please 100mg Oral Film English & Generic Names Explainedβ€’ Super P-Force Oral Jelly (Sildenafil/Dapoxetine) 160mg (7 Packets) for Those Seeking Longer-Lasting Endurance and Sustained Firmness: Cialis vs. Levitra vs. Spedra vs. Viagra: In-Depth Comparison of Four ED Medications and Buying Guideβ€’ Cialis (tadalafil) 5mg (40 tablets) for Men in Their 20s-30s Nervous About Intimate Performance: PTT/Dcard User Reviews: Real-World Effectiveness, Personal Experiences, and Frequently Asked Questionsβ€’ Super Spedra Green Water Ghost 160mg (10 tablets) for Men in the Process of Quitting Smoking or Adjusting Alcohol Habits: How to Spot Counterfeit vs. Genuine: Anti-Counterfeit Labels, Batch Verification, and Authenticity Guideβ€’ Super Double Viagra Peak Black P 210mg (10 tablets) for Men Aged 40-50 Experiencing Age-Related Decline in Function: How to Spot Counterfeit vs. Genuine: Anti-Counterfeit Labels, Batch Verification, and Authenticity Guideβ€’ πŸ₯ How to verify authentic Nirvalab Oral Soluble Film 30mgβ€’ πŸ” Check the 2026 official price list for Nookie Oral Film 120mgβ€’ πŸ“š Medical references for P-Force 200mgβ€’ πŸ’Š Dosage and safety guide for Cialis