Took 20mg of ritalin (methylphenidate) and the veins in my arms and legs are more visible. no other symptoms. is this normal? or could it be from the summer temp?

Ritalin (methylphenidate): Ritalin (methylphenidate) may increase your heart rate and blood pressure, although the veins in your arms and legs are most likely to be engorged if you are retaining fluids in your system, or there is a cardiac failure. You deserve a thorough cardiac evaluation before starting stimulants, and each year thereafter. Please ask your doctor to order an ekg and routine blood work and urinalysis to be safe.