DISCLAIMER: I have no medical license or education. All my knowledge comes from Wikipedia, Reddit and my personal experience. The below is not a qualified medical advice nor a credible research result.

No side effects specifically related to long term use are known so far. Regular doctor check-ups don't show anything that could be related. Stopping taking piracetam (I do it occasionally for a month or two as a safety measure) is also never a problem - absolutely no withdrawal of any kind. The Russian instruction manual put in every box of piracetam there specifically recommends (at least it did a decade ago) to start taking it regularly as you reach 50 and keep taking it forever to fight brain aging, European instructions (piracetam is an approved over-the-counter medicine in some and a prescription medicine in others) lack this recommendation and recommend to avoid taking piracetam for periods exceeding 8 weeks without a doctor recommendation.

As for short-term side-effects (that can be experienced until a pill wears off) - it can increase anxiety/aggressiveness/paranoia etc slightly (which can affect you occasionally if you loose conscious awareness of the fact your feelings are altered by the substance, as long as you are conscious about it it is rarely a problem) and make it harder to fall asleep so don't take it at evenings and avoid it if you are prone to anger. Keeping your mouth shut is also harder under piracetam, make sure you don't tell people anything you shouldn't.

You may need (not necessarily, it depends) to be taking piracetam (I take 1200 mg 1-2 times a day usually, up to 8 times a day occasionally) for up to some weeks before you start feeling the difference.

WARNING: I'd also warn against taking it before driving (or try it with a bicycle first at least and make sure you do good at maintaining proper concentration), especially if you have ADHD - a piracetam-stimulated mind can start wandering between random ideas too vigorously occasionally and you can forget to pay enough attention to the road.

It also makes many brain-affecting substances (including alcohol) act stronger and wear-off faster and cures/prevents (not entirely but the difference can hardly go unnoticed) hangovers.

It plays amazingly well with alprazolam by eliminating drowsiness, maintaining sharp mind and vigor while alprazolam keeps your mood good and helps to concentrate. I believe it may also fight addiction/tolerance development but I have never been taking alprazolam or anything like that long enough to develop addiction.

It is also important to mention that modern piracetam derivatives (like carphedon or sunifiram) differ significantly and you can't extend all the above to them. They act instantly and produce great synergic effect with piracetam (piracetam + carphedon feels like enlightenment the first time you experience that) but are much less dosage-safe (never overdose sunifiram!) and play different with other stuff e.g. carphedon does NOT play nice with benzodiazepines according to my experience (but sunifiram does, sunifiram + piracetam + alprazolam = great productivity; and sunifiram is also known to increase neuroplasticity in particular AFAIK).

WARNING: I have no idea how any of the substances mentioned above may interact with statin or anticoagulants or affect blood pressure, please be very careful and consult with you doctor if you can (no american doctor can recommend piracetam or anything like that officially as these are not approved by FDA but maybe they should have a chance to warn you if your condition or the medicines you take are known to be incompatible with piracetam).