Complex sentence: Reprints of the articles can be distributed to doctors in their offices or at medical meetings by drug company representatives in lieu of product brochures, which might be illegal, if they were to otherwise advocate use of the drug for non-approved indications or dosages.
Split into simpler sentences: Reprints of the articles can be distributed to doctors in their offices or at medical meetings by drug company representatives "in lieu" of product brochures. This practice might be illegal if it effectively constitutes advertising or advocating use of the drug for non-approved indications or dosages.