Doctors start with low doses on many medications and slowly increase (titrate) the dosage. This is done so the doctor can monitor the patient for side-effects, adverse reactions, and efficacy. A dose that is extremely low could possibly be effective for one person and have no effect at all in another. Let's say 50 mgs of something is an effective dose for one person...if the doctor automatically started that person on 100 mgs because that is the average effective dose, then they would never know that person could have efficacy with a lower dose. It's also important to allow the body time to adjust. Exercise is a good analogy here. If a person has not been exercising and suddenly goes out an tries to run a marathon, there are going to be problems. It is much better to start exercising slowly...be able to walk a mile before trying to run one. It is the same idea with medication.