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Ontario Public Drug Programs

Glossary – B

This glossary provides brief explanations of terms used in the Ontario Public Drug Programs web pages. To access a term definition, select the appropriate letter from the alphabet below.


In clinical trials, baseline refers to patient information gathered at the beginning of a clinical trial, before participants begin to receive the experimental drug treatment. Similar information gathered during or after the clinical study is assessed against the baseline values.

The safety and efficacy of a drug is often determined by monitoring changes from baseline values.


Bias refers to a point of view that prevents a researcher or clinician from rendering an impartial judgment about issues relating to that point of view. In clinical studies, researchers control for bias by blinding and randomization (See Blind and Randomization).

Publication bias occurs when the likelihood of a study being published varies with the results it finds. Usually, this occurs when studies that find a significant positive effect are more likely to be published than studies that do not find a significant positive effect, making it appear from surveys of the published literature that treatments are more effective than is actually the case.

Bias occurs when journals prefer and select studies with significant positive results, and when interested parties, such as drug manufacturers, release only selected results.

A systematic review (See Systemic Review) tries to detect publication bias by plotting sizes of trials against results. The approach assumes that larger trials are more likely to be published, regardless of their results. If a systematic review finds evidence of publication bias, it should report that. Often, publication bias takes the form of slower or less prominent publication of trials with less interesting results.

Bill 102 (See Transparent Drug System for Patients Act)
Bioavailability Bioavailability refers to the rate and extent to which a drug is absorbed becomes available at the site in the body that requires treatment. For example, for drugs that work on the whole system, bioavailability refers to the rate and extent to which an active substance is absorbed and becomes available in the body’s general circulatory system.
Bioequivalence Two drugs are considered bioequivalent if they are the same strength of the same medicinal product in the same dosage, and become available to the body at the same time. Drugs are also considered bioequivalent, for example in the case of a brand name or generic product, if they provide the same medicinal product in different chemical form or different dosage form/different strength but become available at the treatment site in the body at the same time and with similar safety and efficacy.
Bioethics The ethics of medical and biological research and practice.
Blind A randomized clinical trial is "blind" if the participant is not told which treatment group, or arm, of the trial he or she is participating in. For example, participants are unaware of whether they are in the experimental group, receiving a new therapy, or the control arm of the study. (See Single-blind study and Double-blind study).
Bridge therapy

The traditional management of blood thinning for hospitalized patients is often referred to as "bridge" therapy. Bridge therapy, or an alternative drug, is ordered when a patient needs to have their current drug therapy interrupted for a time to prepare for surgery or another procedure. Physicians prescribe bridge therapy when they feel that keeping the patient on their current drug may be dangerous and result in complications, but when the patient requires some form of drug therapy.

Bridge therapy can also refer to the use of a short-term drug that acts as a bridge until the drug used as the regular maintenance treatment can achieve its therapeutic level and is shown to be working.

Budget Impact Analysis (BIA) An analysis of the impact of a new drug product on drug plan spending.

For More Information

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