Viagra 100mg x 12 Tablets

Viagra 100mg (Sildenafil Citrate) stands as one of the most well-known examples in pharmacological education for studying enzyme inhibition, cardiovascular physiology, and drug design.
Developed in the late 20th century, sildenafil has become an essential case study for illustrating how molecular targeting can address specific physiological pathways, particularly through phosphodiesterase type-5 (PDE5) inhibition.

In academia, Viagra is not only recognized for its clinical relevance but also as a powerful learning tool in biochemistry, medicinal chemistry, and pharmacodynamics.

2. Chemical Composition and Classification

Chemical Name: Sildenafil Citrate
Molecular Formula: C22H30N6O4S
Molecular Weight: 474.58 g/mol
Drug Class: Phosphodiesterase type-5 (PDE5) inhibitor
Dosage for study model: 100mg tablet (standard educational reference)

Its structure and molecular interactions are widely used to teach structure–activity relationships (SAR) in drug chemistry programs.

3. Historical Development

Sildenafil was initially synthesized by Pfizer researchers during cardiovascular studies aimed at treating angina pectoris (chest pain caused by reduced heart blood flow).
Unexpectedly, the compound demonstrated significant vasodilatory effects on penile tissue due to PDE5 inhibition — a pivotal discovery that revolutionized targeted drug therapy research.

In education, this history demonstrates the serendipitous nature of drug discovery and underscores the importance of rigorous clinical observation.

4. Mechanism of Action

Viagra’s educational importance lies in its precisely understood biochemical mechanism.
Sildenafil selectively inhibits PDE5, an enzyme responsible for degrading cyclic guanosine monophosphate (cGMP) in smooth muscle tissue.

Mechanism summary:

Sexual stimulation releases nitric oxide (NO).
NO activates guanylate cyclase, increasing cGMP.
Elevated cGMP causes smooth muscle relaxation and vasodilation.
PDE5 breaks down cGMP — sildenafil prevents this degradation, maintaining higher cGMP levels.

This chain of reactions makes Viagra an ideal compound for teaching signal transduction, enzyme kinetics, and receptor-mediated responses.

5. Pharmacokinetics

Viagra 100mg provides a useful model for learning about absorption, distribution, metabolism, and excretion (ADME) processes in pharmacokinetics.

Absorption: Rapid oral absorption; peak plasma levels within 30–120 minutes.
Bioavailability: Approximately 40%.
Metabolism: Primarily hepatic via cytochrome P450 (CYP3A4, CYP2C9).
Half-life: 3–5 hours.
Excretion: Metabolites eliminated via feces and urine.

These parameters are discussed in educational pharmacology for understanding drug–enzyme interactions and hepatic metabolism.

6. Structural and Chemical Properties

Viagra’s molecular structure demonstrates heterocyclic design principles.
It consists of a pyrazolopyrimidinone core and a sulfonamide moiety — features that promote strong hydrogen bonding with PDE5’s active site.

Students studying medicinal chemistry can model sildenafil’s 3D conformation using computational software to visualize ligand–receptor docking and electrostatic interactions.

7. Academic Importance in Pharmacology

In university and professional education, Viagra is utilized as:

A model PDE5 inhibitor for pharmacodynamics lessons.
A case study in drug repurposing.
A benchmark compound for teaching cardiovascular pharmacology.
A tool for illustrating clinical trial design and ethics in pharmaceutical research.

By analyzing its development and regulation, students gain insight into real-world drug approval and safety processes.

8. Physiological Relevance

Viagra helps explain vascular physiology and smooth muscle regulation in both cardiovascular and urogenital systems.
Educators use it to demonstrate:

Endothelial function and nitric oxide pathways.
The role of cGMP as a secondary messenger.
Vascular smooth muscle relaxation mechanisms.

These lessons provide a foundation for understanding drug-induced vasodilation and hemodynamic modulation.

9. Laboratory and Research Applications

In laboratory settings, sildenafil is studied for:

PDE5 enzyme inhibition assays.
Spectrophotometric and chromatographic analysis.
Pharmacodynamic modeling in isolated tissue experiments.
Comparative enzyme selectivity testing (PDE1–PDE11).

These experiments help students and researchers grasp enzyme kinetics, substrate competition, and signal amplification principles.

10. Educational Comparison with Similar Compounds

Viagra is often compared with other PDE5 inhibitors such as Tadalafil (Cialis) and Vardenafil (Levitra) in educational programs.

Comparative teaching points include:

Molecular structure differences.
Half-life and onset time variations.
Selectivity profiles and pharmacokinetics.

Such comparisons enhance understanding of drug optimization and SAR analysis.

11. Drug Metabolism and Enzymatic Interaction

The metabolism of sildenafil involves CYP3A4 and CYP2C9 pathways, providing an excellent platform for studying enzyme induction, inhibition, and pharmacogenomics.

Students learn how hepatic cytochrome P450 systems affect drug clearance, interactions, and personalized medicine concepts.

12. Clinical Pharmacology Education

In medical and pharmacy schools, Viagra 100mg serves as an example for:

Patient-specific drug dosing models
Adverse reaction analysis (e.g., hypotension, visual disturbances)
Drug–drug interaction prediction
Therapeutic index calculation

By analyzing these elements, learners gain experience with real-world pharmacotherapy evaluation techniques.

13. Ethical and Educational Usage

All educational references to Viagra must remain strictly academic.
It is essential that the compound be discussed only in approved institutional contexts under qualified supervision, respecting ethical boundaries in human pharmacology education.

14. Future Research Directions

Modern research explores novel PDE5 inhibitors, nanoparticle-based drug delivery, and sildenafil analogues for pulmonary hypertension and vascular disorders.
In educational contexts, this reflects the evolution of rational drug design and the advancement of targeted pharmacotherapy.

15. Conclusion

Viagra 100mg (Sildenafil Citrate) remains a cornerstone in pharmacological education, exemplifying how a single molecular target can revolutionize medical understanding.
Through its mechanism of PDE5 inhibition, it offers profound teaching value in biochemistry, physiology, medicinal chemistry, and clinical pharmacology.

By studying Viagra’s discovery, mechanism, and structure, students learn critical lessons in drug design, enzyme regulation, and ethical pharmaceutical development.

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