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Wait, do you mean Syntrophin? The only hits I could find for Sytropin were for a fictional drug.
If you mean Syntrophin, I hope the doctor has prescribed it based on a medical condition and not just because you want to grow taller... 5'5" is a very good height for a girl and Syntrophin is typically used for bodybuilding and is normally not safe for minors unless it's for a medical condition because they are still growing.
Really, nothing can force your body to grow taller than your DNA says you will. There are some things that can take away from your potential height (including smoking, drugs, caffeine, etc), so as long as you stay away from those, exercise at least on a semi-regular basis, and have a healthy diet, you should grow as tall as you're supposed to. Besides all that, your growing age normally peaks around 20 years old, so since you're younger than that, you've got plenty of time to finish growing and any HGH pills (or other "artificial growth" products) can actually be detrimental to your potential height and/or health.
Source(s):
Health/nutrition classes, a quick search on Yahoo, and personal research in my role as a Product Specialist for a vitamin company