Whatever the route of administration, a drug must reach its site of action. In order to do this, the drug will have to cross several cell membranes to reach the blood (unless it is injected intravenously).
The three ways by which substances, including drugs, can cross cell membranes are simple diffusion, facilitated diffusion and active transport. Read more

The importance of pharmacology to health care professionals cannot be overestimated. Members of the three professions, physiotherapy, podiatry and radiography, encounter patients on a daily basis, many of whom will be on drug therapy. Patients are increasingly likely to be receiving at least one drug; many older patients are likely to be on more than one drug, and prescription of eight or nine drugs at the same time is not uncommon. This is known as polypharmacy and it increases the chance of patients experiencing adverse effects or the effects of drug–drug interactions.
Depending on the nature of their work, health care professionals may spend some considerable time with individual patients who might have questions about their drug therapy. Some health care professionals may be treating mainly older patients, or younger patients or high-risk patients, and will become experienced and familiar with drugs in their areas of expertise. Read more