This is a medication used to reduce blood pressure. One of the various side effects, says one reader, is a feeling of pins and needles and/or pain in the muscles. What causes this sensation? Generally, most of these medicines deplete essential nutrients, and this nutrient loss may be causing this sensation. Vitamin B6 is good for "pins and needles," and you may also want to try niacin. Definitely avoid St. John's Wort here, as that can cause the same kinds of needly feelings.