Zenegra (Sildenafil Citrate) is a PDE5 inhibitor medication used to treat erectile dysfunction by enhancing blood flow to the penis during sexual stimulation. It works by blocking the PDE5 enzyme, which helps maintain the erection-enhancing effects of nitric oxide, though sexual arousal is still required for the medication to be effective. Available in 25mg, 50mg and 100mg tablets, Zenegra typically takes effect within 30-60 minutes and remains active for 4-5 hours. While not an aphrodisiac or permanent cure for ED, it provides temporary improvement in erectile function when used as directed under medical supervision.

How to Take:

• Take one tablet 30-60 minutes before sexual activity (optimal timing may vary)
• Swallow whole with a glass of water (do not crush or split tablets)
• Maximum dosing frequency: Once per 24 hours

Dosage Guidance:

• Starting dose: Typically 50 mg (adjusted based on effectiveness/tolerance)
• May be reduced to 25 mg if experiencing side effects
• May be increased to 100 mg if insufficient response

Food/Alcohol Considerations:

• Can be taken with or without food
• Avoid high-fat meals (may delay absorption)
• Limit alcohol (may increase side effects like dizziness)

Missed Dose:

• Not applicable (taken only as needed before sexual activity)

Storage:

• Keep in original container at room temperature (15-30°C)
• Protect from moisture and direct light

Important Notes:

• Requires sexual stimulation to work
• Does not protect against STIs – use protection as needed
• Do not combine with nitrates or recreational ED drugs

Common Side Effects

(May affect up to 1 in 10 users)

• Headache
• Flushing (redness/warmth in face/neck)
• Indigestion or upset stomach
• Nasal congestion
• Mild dizziness
• Temporary visual changes (mild blue tint, increased light sensitivity)

These effects are usually mild and resolve within a few hours.

Less Common Side Effects

(May affect up to 1 in 100 users)

• Back pain or muscle aches
• Nausea
• Blurred vision
• Dry mouth
• Rash

Serious Side Effects

(Stop use and seek immediate medical help if experiencing):

• Sudden vision loss (rare cases of NAION – ischemic optic neuropathy)
• Hearing loss or ringing in ears
• Chest pain, irregular heartbeat, or shortness of breath
• Erection lasting >4 hours (priapism – requires emergency care)
• Severe allergic reaction (swelling of face/lips, difficulty breathing)

Managing Side Effects

1. For headache/flushing: Drink water, rest, consider mild pain reliever (avoid nitrates)
2. For indigestion: Take with a light meal next time
3. For dizziness: Sit or lie down until it passes
4. For vision changes: Avoid bright lights and driving until normal vision returns

Special Considerations

• Heart patients: Increased risk of cardiovascular side effects
• Elderly: May be more sensitive to effects
• Underlying eye conditions: Higher risk of vision complications

Primary Medical Use:

Zenegra is prescribed to treat erectile dysfunction (ED) in adult men. It helps achieve and maintain an erection sufficient for sexual activity when taken with sexual stimulation.

Mechanism of Action:

• Inhibits phosphodiesterase type 5 (PDE5)
• Enhances the effects of nitric oxide in penile tissue
• Promotes blood vessel relaxation and increased blood flow to the penis

Important Notes About Use:

1. Not an aphrodisiac – requires sexual arousal to work
2. Does not cure ED – provides temporary improvement during the 4-5 hour window
3. Not for women or children – approved only for adult male use
4. Off-label uses (under medical supervision only):
   • Pulmonary arterial hypertension (under different brand names)
   • Altitude sickness prevention (investigational use)

Expected Results:

• Onset: 30-60 minutes after taking
• Duration: Up to 4-5 hours of improved erectile function
• Effectiveness: About 80% of men report improved erections

When Not Effective:

• Without sexual stimulation
• With excessive alcohol consumption
• If taken with high-fat meals (may delay absorption)

Key Safety Considerations:

Cardiovascular Risks:

Zenegra may cause potentially dangerous drops in blood pressure, particularly in patients with pre-existing heart conditions. Men with unstable angina, recent heart attack (within 6 months), or severe heart failure should avoid use. Sexual activity itself poses cardiac risk for some patients.

Vision Complications:

Rare cases of sudden vision loss (NAION) have been reported, particularly in those with:

• Pre-existing optic nerve issues
• Hypertension
• Diabetes
• High cholesterol
• Smoking history

Hearing Effects:

Sudden decreases in hearing or hearing loss may occur, sometimes accompanied by tinnitus or dizziness. Discontinue use immediately if these symptoms appear.

Priapism Risk:

Prolonged erections lasting more than 4 hours require emergency medical attention to prevent permanent tissue damage and impotence. Higher risk in patients with:

• Sickle cell anemia
• Multiple myeloma
• Leukemia
• Penile deformities

Special Population Concerns:

• Elderly: Increased sensitivity to side effects
• Renal/Hepatic Impairment: May require dose adjustment
• Concurrent Medications: Numerous dangerous interactions possible

Important Precautions:

• Never use with nitrates or recreational “poppers”
• Avoid grapefruit/grapefruit juice (may increase side effects)
• First-time users should take lowest effective dose
• Report any chest pain during sexual activity

Black Box Warnings (Most Serious Risks)

1. Nitrate Medication Interaction

• Severity: Life-threatening
• Effect: Profound hypotension (dangerously low blood pressure)
• Includes: All nitrate forms (NTG tablets/spray/patches, isosorbide) and recreational “poppers”
• Action: Absolute contraindication – never combine

2. Cardiovascular Risks

• Concerns:
  • Sudden cardiac death
  • Myocardial infarction
  • Stroke
  • Arrhythmias
• At-Risk Patients:
  • History of heart disease
  • Resting hypotension (<90/50) or hypertension (>170/100)
  • Recent cardiac events (within 6 months)

Other Critical Warnings

Vision Loss (NAION)

• May occur within hours of dosing
• Risk factors: >50 years old, diabetes, hypertension, smoking
• Permanent in some cases

Hearing Loss

• Sudden sensorineural hearing impairment
• May be accompanied by tinnitus/dizziness
• Mechanism unclear

Priapism

• Erections >4 hours require emergency treatment
• Can lead to permanent erectile dysfunction if untreated
• Higher risk with sickle cell anemia/leukemia

Hypotension

• Enhanced by:
  • Alpha-blockers
  • Antihypertensives
  • Alcohol
• May cause syncope

Special Populations

• Severe Hepatic Impairment: Maximum 25mg dose
• Severe Renal Impairment (CrCl <30): Start with 25mg
• Elderly: Increased sensitivity to effects

Important Notice:

Zenegra should only be prescribed after:

• Thorough cardiovascular assessment
• Review of all concurrent medications
• Discussion of risk factors

Standard Adult Dosage for Erectile Dysfunction

Initial Recommended Dose:

• 50 mg taken as needed approximately 30-60 minutes before sexual activity

Dose Adjustment:

• May be increased to 100 mg if insufficient response (maximum recommended dose)
• May be decreased to 25 mg if experiencing side effects

Maximum Frequency:

• Once daily (24-hour interval between doses)

Special Population Adjustments

Elderly Patients (≥65 years):

• Consider starting with 25 mg dose
• Increased sensitivity to side effects possible

Hepatic Impairment:

• Mild to moderate (Child-Pugh A-B): 25 mg starting dose
• Severe (Child-Pugh C): Not recommended

Renal Impairment:

• Mild to moderate (CrCl 30-80 mL/min): No adjustment needed
• Severe (CrCl <30 mL/min): 25 mg starting dose

Concomitant Medications:

• With CYP3A4 inhibitors (e.g., erythromycin, saquinavir, ketoconazole):
  • Maximum 25 mg dose
  • Increase dosing interval to 48-72 hours

Administration Guidelines

Optimal Timing:

• Take 30-60 minutes before anticipated sexual activity
• May take as early as 4 hours before (with reduced efficacy)

Food Interactions:

• High-fat meals may delay onset of action by ~1 hour
• Best taken on empty stomach for fastest effect

Missed Dose:

• Not applicable (taken only as needed before sexual activity)

Storage Conditions:

• Store at 20-25°C (68-77°F)
• Protect from light and moisture
• Keep in original packaging

1. Nitrate Medications (Absolute Contraindication)

• Examples: Nitroglycerin, isosorbide dinitrate, amyl nitrite (“poppers”)
• Risk: Severe hypotension (dangerously low blood pressure)
• Mechanism: Combined vasodilatory effects
• Management: Never co-administer; wait 24 hours after last sildenafil dose before nitrates

2. Alpha-Blockers

• Examples: Tamsulosin, doxazosin, terazosin
• Risk: Symptomatic hypotension
• Mechanism: Additive blood pressure lowering
• Management: Start with 25mg sildenafil if combination unavoidable

3. CYP3A4 Inhibitors

• Strong Inhibitors:

  • Examples: Ketoconazole, itraconazole, ritonavir
  • Effect: 3-10 fold increase in sildenafil levels
  • Recommendation: Maximum 25mg dose every 48 hours

• Moderate Inhibitors:

  • Examples: Erythromycin, saquinavir, grapefruit juice
  • Effect: 2-3 fold increase in sildenafil levels
  • Recommendation: Maximum 25mg dose every 24 hours

4. Antihypertensives

• Examples: Amlodipine, valsartan, hydrochlorothiazide
• Risk: Additive blood pressure reduction
• Management: Monitor blood pressure; consider lower sildenafil starting dose

5. Alcohol

• Effect: Increased hypotension, dizziness, headache
• Recommendation: Limit consumption to 1-2 drinks

6. Other PDE5 Inhibitors

• Examples: Tadalafil, vardenafil
• Risk: Profound hypotension, increased side effects
• Management: Never combine with other ED medications

Important Notes:

• Always provide complete medication history to prescriber
• Monitor for hypotension when starting new medications
• Report any unusual symptoms immediately
• Avoid grapefruit/grapefruit juice products