How to choose the best drug from various pharmaceutical companies? What will be the key point to select a drug? How to compare a drug among thousands of companies?

Factors to be compared, like -  Effectivity  Patient safety ( side effect and complication) Patient review Doctor's review Ranking, rating and accreditation of pharmaceutical company Price- here I got some app giving information about different price from different companies. Counterfeit medicine- there are some wonderful websites to check duplicate/fake medicine  How can I know about these key points before selecting a drug for my patient?