Sildenafil Citrate Tablets: A Comprehensive Guide to Understanding Uses, Dosage, and Precautions

Sildenafil Citrate Tablets 50 mg: A Comprehensive Guide to Understanding Uses, Dosage, and Precautions

Sildenafil citrate tablets are widely recognized for their role in the treatment of erectile dysfunction (ED) and pulmonary arterial hypertension (PAH). This medication, commonly known by its brand name Viagra, has transformed the lives of millions of men worldwide. In this comprehensive blog post, we will explore various aspects of Sildenafil Citrate Tablets, including their uses, mechanism of action, dosage guidelines, potential side effects, precautions, and other essential information to help you gain a better understanding of this commonly prescribed medication.

Overview of Sildenafil Citrate

Sildenafil citrate is a phosphodiesterase type 5 (PDE5) inhibitor that works by relaxing the smooth muscles and increasing blood flow to specific areas of the body. It was initially developed as a cardiovascular medication but was later discovered to have a significant impact on erectile function.

Uses of Sildenafil Citrate Tablets:

Sildenafil citrate tablets are primarily used to treat erectile dysfunction in men. Additionally, sildenafil is also approved for the treatment of pulmonary arterial hypertension (PAH) in both men and women.

Mechanism of Action and Pharmacokinetics

Mechanism of Action:

Sildenafil citrate inhibits the enzyme PDE5, leading to increase levels of cyclic guanosine monophosphate (cGMP) in the smooth muscle cells. This results in smooth muscle relaxation, vasodilation, and improved blood flow, particularly to the erectile tissue.


Sildenafil citrate is rapidly absorbed after oral administration and reaches its peak concentration in the bloodstream within one to two hours. It undergoes hepatic metabolism and has a half-life of approximately four hours.

III. Sildenafil Citrate for Erectile Dysfunction

Understanding Erectile Dysfunction:

Erectile dysfunction is a common condition characterized by the inability to achieve or maintain an erection sufficient for sexual activity. Various factors contribute to the development of ED, including underlying medical conditions, psychological factors, and lifestyle choices.

Dosage and Administration:

Sildenafil citrate tablets are available in various strengths, with the most common being 25 mg, 50 mg, and 100 mg. The recommended starting dose is typically 50 mg, taken approximately one hour before sexual activity. The dosage may be adjusted based on individual response and tolerability.

Efficacy and Factors Affecting Response:

Sildenafil citrate has been extensively studied and has shown significant efficacy in treating erectile dysfunction. Factors such as the cause of ED, overall health, concurrent medication use, and psychological factors can affect the response to sildenafil therapy.

Potential Side Effects:

Common side effects of sildenafil citrate tablets include headache, flushing, nasal congestion, indigestion, and visual disturbances. Rare but serious side effects, such as priapism (prolonged erection) and sudden hearing or vision loss, require immediate medical attention.

Sildenafil Citrate for Pulmonary Arterial Hypertension
Understanding Pulmonary Arterial Hypertension:

Pulmonary arterial hypertension (PAH) is a progressive condition characterized by high blood pressure in the arteries of the lungs. Sildenafil citrate is approved for the treatment of PAH to improve exercise capacity and delay disease progression.

Dosage and Administration:

The recommended starting dose of sildenafil citrate for PAH is typically 20 mg three times daily. The dosage may be adjusted based on individual response and tolerability. Sildenafil citrate for PAH is available in different formulations, including tablets and oral suspension.

Efficacy and Factors Affecting Response:

Sildenafil citrate has been shown to improve exercise capacity and delay disease progression in patients with PAH. However, individual responses may vary, and factors such as disease severity, concurrent medication use, and underlying conditions can influence treatment outcomes.

Potential Side Effects:

The side effects of sildenafil citrate for PAH are generally similar to those for erectile dysfunction. However, patients with PAH may be more susceptible to cardiovascular effects, such as a drop in blood pressure. Close monitoring and regular follow-up with a healthcare provider are crucial for managing potential side effects.

Precautions and Considerations

Precautions and Contraindications:

Sildenafil citrate should be used with caution in individuals with certain medical conditions, including cardiovascular disease, liver or kidney impairment, retinal disorders, or a history of priapism. It is contraindicated in combination with certain medications, particularly nitrates.

Drug Interactions:

Sildenafil citrate can interact with various medications, including nitrates, alpha-blockers, certain antifungal agents, and protease inhibitors. These interactions can lead to potentially serious adverse effects, such as severe hypotension.

Special Considerations:

Special considerations should be given to certain populations, including older adults, individuals with anatomical deformities of the penis, and patients with preexisting eye conditions. Close monitoring and appropriate dose adjustments may be necessary in these cases.


Sildenafil citrate tablets have revolutionized the treatment of erectile dysfunction and pulmonary arterial hypertension, significantly improving the quality of life for many individuals. As a widely prescribed medication, understanding the uses, dosage guidelines, potential side effects, and precautions associated with sildenafil citrate is crucial for both patients and healthcare providers. By adhering to recommended dosages, following precautions, and seeking medical guidance, individuals can maximize the benefits of sildenafil citrate while minimizing the risk of adverse effects. If you have any concerns or questions regarding the use of sildenafil citrate tablets, consult your healthcare provider for personalized advice and guidance.

Master Formula Record

PURPOSE: This Master Formula Record is written to describe the formulae, manufacturing procedure, specifications, packing details of dosage form.

SCOPE:  This MFR is performed and is applied during the manufacturing of dosage form.

RESPONSIBILITY / ACCOUNTABILITY: It is the responsibility of  Manufacturing Chemist to follow and adhere to this SOP. The Production Pharmacist, QC/QA Manager are accountable for the strict adherence to the master formula.





Each film coated Tablet contains:

Sildenafil Citrate

 Equitant to Sildenafil                                             50 mg


Steam Jacketed Starch Paste Preparation Tank
Sifter Machine – I
Roto Cube Blender –I
Rapid Mixer Granulator
Multi Mill
Fluidized Bed Drier
Oscillating Granulator
Sifter Machine – II
Sifter Machine – III
Roto Cube Blender – II
Roll Compactor Machine
Tablet Compression
Tablet Compression Machine 27 Stations
Dedusting Machine
Tablet Inspection Machine
Colloidal Mill
Rapid Coat Tablet Coating Machine
Single Track Blister Packing Machine


Aerosil : 0500 Kg

D.C.P : 25.000 Kg

Iso Propyl Alcohol :16.500 Kg

Isopropyl Alcohol :8.000 Kg

Indigo Carmine Al Lake :0.017 Kg

Instacoat Indigo Carmine :2.100 Kg

Lactose :5.899 Kg

Micro Crystalline Cellulose Phosphate :8.500 Kg

Magnesium Stearate :0.756 Kg

Methylene Chloride :30.000 Kg

Sodium Benzoate :0.077 Kg

Sodium Starch Gycolate :1.000 Kg

Starch :1.500 Kg

Sildenafil Citrate :10.774 Kg

Talcum :1.000 Kg

Instacoat Brilliant Blue :0.709 Kg

PVPK-30 :0.500 Kg


  •  104 MM CLEAR (PVC)


Moisture content of powder should be less than 2.0 %.

Average weight of each Tablet is 350 milligrams.

Weight Variation Limit for average weight of 20 tablets is +0%.

Friability limit for 20 Tablets is not more than 1.0 %.

Hardness of the Tablets varies between 2 – 4 kg/cm2.

Disintegration time for each Tablet is not more than 30 minutes.

Mix the batch, compress and de-dust the tablets and also perform the primary packing of Tablets at temperature not more than 250


Theoretical Yield is 7.12 Lac Tablets.

Expected Practical Yield is 7.12 Lac + 2% Tablets.

Packing Details:

Use PVC 110 mm Clear and Aluminium foil for blister packing.

Blister Pack the inspected and coated tablets by using Single Track Blister Packing Machine as per its SOP.

Put 10 strips each containing 3 tablets in each carton.

Seal the each carton from both ends with cello tape.

Pack such 10 cartons in specified small-corrugated box D-46S. Seal each corrugated boxes with adhesive tape.

Pack such 12 corrugated boxes in specified corrugated box D-46 to give a pack size of 120 x 10 x 3 tablets.

Seal the each corrugated box with adhesive tape and label it properly by affixing the specified label.


Preparation of Starch Paste:

Prepare the starch paste in the manner given below using Steam Jacketed Starch Paste Preparation Tank by operating it as per its SOP.

Dissolve 0.178 kgs of Sodium Benzoate in 1 Ltr of Purified water and stir continuously.

Add 3.489 kgs of Starch in 7.0 Ltrs Purified  water and stir continuously to make slurry.

Add the solution of sodium benzoate and starch slurry with constant stirring to get a uniform paste.


Fit the mesh #40 Stainless Steel Sieve on the Sifter-I as per its SOP.

Sift all the ingredients through it and collect separately in Stainless Steel Container.


Blend the following ingredients using Roto Cube Blender by operating it as per its SOP for 15 minutes and collect in Stainless Steel Container.

  • 55.180 kgs of Di Calcium Phosphate
  • 19.580 kgs of Lactose
  • 14.240 kgs of M.C.C.P

Wet Granulation:

Mix the above blended ingredients with the Starch paste using Rapid Mixer Granulator by operating it as per its SOP. Add starch paste in such a manner by following the procedure given below so as to achieve proper wetting.

Divide the blended powder in 5 equal parts.

Divide the prepared starch paste in 5 equal parts.

Mix the one part of blended powder and starch paste together in Rapid Mixer Granulator.

Similarly mix another part in same manner.

Wet Screening:

Pass the wet dough through a Multi Mill by operating it as per its SOP to convert the moist mass into coarse, granular aggregates.


Dry the granules in Fluidized Bed Drier by operating it as per its SOP at temperature 600 – 700 C for 30 minutes. Cool the granules to achieve room temperature.


Fit the mesh # 14 Stainless Steel Sieve on the Sifter-II as per its SOP. Sift all granules through it and collect in Stainless Steel Container. Break the oversized granules left over the mesh in Oscillating Granulator by operating it as per its SOP and resift them.

Check the total weight of dried granules. Determine the loss on drying and percentage yield of dried granules.


Lubricate the sifted granules and above compacted material together along the following ingredients in Roto Cube Blender by operating it as per its SOP for 15 minutes and collect in Stainless Steel Container.

  • 1.780 kgs of Magnesium Stearate
  • 1.780 kgs of Talcum
  • 0.890 kgs of Sodium Starch Glycolate

Send the granules for bulk testing to Quality Control Department for assay of Active Ingredients.


Shift all the granules for compression to Tablet Compression Machine 27 Stations by operating it as per its SOP and collect the compressed tablets in Stainless Steel Container.

Tablet Inspection:

Transfer the all tablets to tablet inspection machine and sort out the defected tablets by operating it as per its SOP  and collect the selected tablets in Stainless Steel Container. 

Coating of the tablet:

Dissolve 3.987 kgs of Instacoat Indigo Carmine in 32.432 kgs of Isopropyl Alcohol. Then add 118.976 kgs of Methylene chloride to this solution. Collide the solution by colloidal mill as per SOP. Now start coating of the tablets by using Rapid Cota Tablet Coating Machine by operating it as per its SOP and collect the coated tablets in Stainless Steel Container.

Tablet Inspection:

Transfer all coated tablets to tablet inspection machine and sort out the defected tablets by operating it as per its SOP.Collect the selected tablets in Stainless Steel Container.

Blister Packing:

Shift the inspected tablets to blister section and blister pack them using Single Track Blister Packing Machine by operating it as per its SOP.


 The following in-process controls should be maintained during the processing:

Check Raw materials used for manufacturing purpose are all approved materials and have ‘Released’ labels fixed on it.

All weighed Raw materials should be counter-checked by Assistant Manufacturing Chemist. If any discrepancy is noticed, it should be immediately brought to the notice of Production Pharmacist and QC/QA Manager.

Physical characteristics of Raw material like colour, odour, and consistency are checked before compounding.

Humidity and temperature should be maintained during the compression of thermolabile products.

Sample of dried granules should be sent to Quality Control Department for the determination of Moisture content.

The total weight of blended powder should be checked in the presence of Assistant Manufacturing Chemist and record the same in Batch Manufacturing Record.

Bulk sample should be sent for analysis to Quality Control Department before starting compression of tablets.

Weight Variation: I) Intermittently weight variation of compressed tablets should be checked at 30 minutes interval by the Assistant Manufacturing Chemist and record for the same should be kept in Batch Manufacturing Record.

Out-of-limit tablets should be checked by Weight Variation Method as given below:

Take the average weight of 20 tablets on the calibrated balance and calculate the upper and lower limit as per the table given below in accordance with IP/BP:

80mg or less                                10
More than 80mg and less than 250mg                                 7.5
250mg or more                                  5

Take the weight of individual tablets and check if all the tablets are lying with in the limits.

Select the tablets only if no more than two tablets are out of percentage limit and if no tablet differs by more than two times the percentage limit, otherwise reject the tablets.

Adjust the desired weight of the tablets in the Compression Machine by moving weight adjustment cam clockwise or anticlockwise accordingly as per the Standard Operating Procedure of Compression Machine.

Re-check the weight of tablets for further adjustment, if any.

Thickness of Tablets:

Thickness of the tablets should be determined by means of the vernier caliper. The thickness of the tablet should be checked whenever weight adjustments are made.

Hardness of the tablets:

The equipment used is the ‘Monsanto’ type hardness tester. Hardness of the compressed tablets should be checked at regular interval to determine the need for pressure adjustments on the tableting machine.

Hardness of tablets varies between: 2-4 Kg/cm2.


‘Roche Friabilator’ is used for measuring the Friability. The instrument is designed to evaluate the ability of the tablet to withstand abrasion in packaging, handling and shipping.

Adjust the instrument to 25 RPM before adding the tablets.

Weigh 20 Tablets on calibrated balance. Transfer the tablets in the plastic chamber. Close the drum tightly.

Switch on the apparatus. Operate the Friabilator for 100 revolutions.

De-dust and reweigh the tablets. Loss in weight indicates the ability of tablets to withstand the wear.

Take 10 tablets to check the friability, when the average weight of tablet is 1g or more than 1g.

Friability Limit  = Less than 1.0%

Disintegration Test:

Disintegration is the time required for the group of tablets to disintegrate into the particles. Disintegration Test should be carried out at regular interval of 1 hour by using Disintegration Test Apparatus.

The tube assembly unit is removed from the glass beaker and from each tube the plastic discs are removed.

Place the tablets in each of 6 tubes along with a plastic disc over the tablets.

The glass beaker is filled with water. The water in the beaker is retained at the temperature of 37+1˚C through out the test by suitably setting the thermostat.

Introduce a tube assembly unit into glass beaker in such a way that wire mesh at the base of each tube is at least 2.5 cm below the surface of liquid when the basket is at highest position.

Switch on the apparatus to move the basket assembly containing the tablets up and down through a distance of 5 to 6 cm at a frequency of 28 to 32 cycles per minute. Start the stopwatch.

When the tablets have disintegrated i.e. when no particles remain on the wire mesh at the bottom of tube, stop the stopwatch. Note the time taken for disintegration of the tablets and record the same in Batch Manufacturing Record.

If one or two tablets fail to disintegrate, the test is to be repeated using 12 tablets.

Disintegration Time of uncoated tablets= Not more than 15 minutes

Disintegration Time of coated tablets= Not more than 30 minutes

Tablets taken for testing and In-process control should not be added to the bulk batch to avoid mix-ups and cross-contamination.

Inspection, sorting of rejected tablets should be done as per SOP.

The strips and cartons should be checked thoroughly for proper batch coding.

Manufacturing Chemist and Production Pharmacist should randomly check that the correct no. of strips are being packed in each cartons and also the number of cartons in each shipper is exactly the same as that shown in proof.

Intimation should be sent to Quality Control Department for finished product sampling and testing.

After the completion of labelling and packaging, the coded cartons should be accounted for and rejected printed material should be destroyed in the presence of QC/QA Manager. Fill the destruction sheet and attach the same in the Batch Manufacturing Record.

It will be ensure that filling or packaging equipment has been properly cleaned after the completion of batch.

Filling or packaging of next product should not commence until the IPQA has given the ‘Line Clearance’.

Pharma WhatsApp Groups for Latest Pharma Jobs, Pharma news and Pharma Post