The liver is definitely one of the organs able to regenerate itself later in life, as long as its relatively intact. Yes milk thistle is one of the better ways for normalizing, detoxifying, and regenerating the liver, as is N-acetyl cysteine and TMG (which greatly lowers liver damaging homocycsteine.) The higher the concentration of silymarin in the milk thistle extract the better, look for at most 80 percent. You can find enough clinical trials demonstrating the benefits of all these things on liver health. This is one of the most important steps in ameliorating statin-induced damage.
To answer your question about contraindications, there are really no true cautions except if you're still taking a statin, warfarin, elavil, or valium. But then, you'd probably have far more to worry about taking these medications alone.... being as in high dosages warfarin is often labeled as rat poison, and I like to regard high-dose statins as 'human poison.'
If there is a true concern, your best bet is to take milk thistle separately, as it can slow down liver enzymes, this perhaps in-turn would make any co-administered drug that much more potent. Otherwise, milk thistle would help protect your liver from damage by most medications, especially if you take prohormones or corticosteroid such as prednisone, a fairly nasty drug.
If cost is a major factor, beyondacenturyonline.com sells fully assayed high-quality bulk powders for far cheaper than the capped store bought versions. They will present certificates of analysis for any powder upon request. There are also little spoons provided to approximate the dosages. Although, there's no hard cold upper limit for milk thistle. They sell a 50 gram bottle of 80% silymarin for $5.50, which is around 120 servings of approx 500mg. Their shipping is also very reasonable.
Beyondacenturyonline.com also sells Liver Support powder, which is a combination of phosphatidylcholine, N-acetyl Cysteine, TMG, and Picroliv. All the truly good things for the liver. Choline, especially phosphatidyl, taken along with milk thistle will help it become more absorbable. Apparently Picroliv derived from the kutkin plant is the only substance more potent than milk thistle in this regard. They sell this at $9.75 for 100 grams.
Also check out Hawthorn for better regulating blood pressure. I hope this has answered your questions.