Adverse event: Any adverse change in health or side effect that occurs in a person who participates in a clinical trial while the patient is receiving the treatment (study medication, application of the study device, etc.) or within a pre-specified period of time after their treatment has been completed.

Bioavailability: The measurement of the extent to which a drug reaches the systemic circulation. It is calculated from the blood samples taken during the trial at different times. The value obtained could be used for a comparison between two formulations, for example.

Biochemistry tests: Analysis of bodily fluids for the determination of levels of sodium, potassium, chloride, bicarbonate, urea, creatinine,calcium, glucose, etc. The results will help determine if the participant can be selected for a specific clinical trial.

Bioequivalence: Term used in pharmacokinetics used to assess if two products can be considered equivalent, the same.

Blinded: Study where some persons involved are prevented from knowing certain information that might lead to conscious or unconscious bias on their part, invalidating the results.

BMI: The Body Mass Index is a number obtained from the comparison of the weight and height of a person. It is one of many criteria used to select a participant.

Dose: Quantity of medication administered.

Fast/Fed state: Clinical trial designed to investigate any differences in absorption of the drug by the body, caused by eating before the drug is given. These studies are usually run with participants being given two identical doses of the drug on different occasions; one while fasted, and one after being fed.

Follow-up visit: Mandatory return visit to the clinical site after the participant has left, to perform additional blood draws or medical supervision.

Formulation: Preparation of the drug which is both stable and acceptable to the patient. For orally taken drugs, this usually involves incorporating the drug into a tablet or a capsule. The formulation can influence bioavailability and hence the activity of a drug.

Generic drug (generics): A drug which is produced and distributed without patent protection on the active ingredient. A generic must contain the same active ingredients as the original formulation. According to the U.S. Food and Drug Administration (FDA), generic drugs are identical or within an acceptable bioequivalent range to thebrand name counterpart. By extension, therefore, generics are considered (by the FDA) identical in dose, strength, route of administration, safety, efficacy, and intended use.

Hematology tests: Require examination and measurement of the cells of blood, as well as blood clotting.

Informed Consent: Form that the participant must read, understand and sign before enrolling in a particular study. This form informs the participant about possible side effects, number of blood draws, etc.

Opiate drugs: Derivatives of constituents found in opium, likemorphine, codeine, thebaine, and papaverine. Could also be semi-synthetic opioids such as heroin, oxycodone, and hydrocodone.

Phase I/IIa: Clinical trial at the first stage of testing in human subjects. Normally, a small (20-100) group of healthy participants will be selected. This phase includes trials designed to assess the safety (pharmacovigilance), tolerability, pharmacokinetics, and pharmacodynamics of a drug.Phase II a is a study in patients.

Pilot study: Small scale preliminary study conducted before the main research in order to check the feasibility or to improve the design of the research.

Plasma:Yellow liquid component of blood in which the blood cells in whole blood are normally suspended. Blood plasma is prepared by spinning a tube of fresh blood containing an anti-coagulant in a centrifuge until the blood cells fall to the bottom of the tube.

Post-dose: Period after the drug has been taken.

Screening: Strategy used to select adequate individuals, according to their health, age, weight, etc., to participate in the clinical trial.

Serum: Plasma with the fibrinogens (glycoprotein responsible for coagulation) removed.

Side effect: See adverse event.

Urin alysis: Array of tests performed on urine.

Definitions adapted from Wikipedia.