Here is the professional and accurate English translation of the text:
Ernafil is a generic brand of Viagra® (Commonly referred to as "Wai Gor" in Hong Kong; Generic Name: Sildenafil).
"Wai Gor" (Viagra) is a medication indicated for the treatment of male erectile dysfunction (ED), with sildenafil as its primary active ingredient. It is classified as a phosphodiesterase type 5 (PDE5) inhibitor, which facilitates erections by increasing blood flow to the penis. "Viagra" is a registered trademark of Pfizer Inc. and is marketed under the name "Wan Ai Ke" in Mainland China. As it is a prescription medication, a medical diagnosis and a valid doctor's prescription are required prior to purchase and use.
Primary Ingredient and Mechanism of Action
- Sildenafil: This is the primary active ingredient in Viagra, classified as a PDE5 inhibitor.
- Mechanism of Action: Sildenafil works by inhibiting the PDE5 enzyme, enhancing the effects of nitric oxide to relax the smooth muscles in the corpus cavernosum of the penis. This process increases blood flow, thereby assisting in achieving an erection.
Important Information About Viagra (Sildenafil)
- Side Effects: Common side effects include facial flushing, headaches, indigestion, and visual disturbances.
- Contraindications: It must not be taken concurrently with nitrate medications (such as nitroglycerin, used to treat angina), as this combination can induce severe hypotension (dangerously low blood pressure).
- Directions for Use: It is recommended to take the medication approximately one hour prior to sexual activity. The specific dosage and timing should strictly follow a doctor's instructions. The standard dosage is 50mg - 100mg, which can be adjusted based on efficacy and tolerance.
- Purchasing: As a prescription medication, it can only be purchased following a medical diagnosis and the issuance of a prescription, or by presenting a valid prescription at a registered pharmacy. The public is strongly advised against purchasing medications from unknown or unverified sources.
