Sildenafil

Sildenafil Basic Facts:

• Type 5 phosphodiesterase (PDE5) inhibitor (competitive binding agent).
• Prevents breakdown of cyclic GMP.
• The molecular structure of sildenafil is similar to that of cyclic GMP.
• Used predominantly in treatment of male erectile dysfunction
• Prolongs penile corporeal smooth muscle relaxation.
• Sildenaphil is only effective when cyclic GMP is present in penile smooth muscle.

Sildenafil Clinical Uses:

• Altitude sickness
• Male erectile dysfunction
• Pulmonary artery hypertension

Sildenafil Adverse Reactions:

• Dyspepsia
• Facial flushing
• Headache
• Nasal congestion
• Priapism
• Visual disturbance of blue/green colour discrimination

Sildenafil Drug Interactions:

• Alpha-blockers - hypotension
• Cimetidine - increases sildenafil concentrations.
• Erythromycin - increases sildenafil concentrations.
• Nitric oxide donors - ie amyl nitrite (Popper)
• Organic nitrates
• Protease inhibitors - increases sildenafil concentrations.

Sildenafil Contraindications:

• Conditions predisposing to priapism.
• Hypotension
• Nitrate use
• Recent cerebrovascular accident
• Recent myocardial infarction
• Retinitis pigmentosa
• Severe hepatic dysfunction
• Severe renal impairment

Sildenafil Pharmacokinetics:

• Absorption reduced if taken with a high fat meal - delays maximum plasma concentration by 1 hour, maximum concentration reduced by 1/3rd.
• Metabolized by liver enzymes.
• Excreted by both the liver & kidneys.

Tags: Altitude Sickness - cGMP - Cyclic GMP - Erectile Dysfunction - Phosphodiesterase - Pulmonary Hypertension - Sildenafil - Sildenaphil
Posted by Medicalchemy
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