Ocular therapeutics Ð Part 10 Basic and ocular pharmacology

The science of pharmacology is concerned with the effects of drugs on the function of living tissues (Greek: pharmakos = drug, logos = study). Since modern medicine relies heavily on drugs as the principal tool for the treatment and prevention of disease, it is important that all clinicians possess a basic understanding of the pharmacological principles that govern their clinical use. These include the mechanisms by which the body handles drugs, so that the optimal dose can be delivered to the target tissue, coupled with an understanding of how drugs act at a cellular or molecular level so as to predict adverse reactions and interactions. A large number of drugs, including both topical and systemic, are used in the treatment and diagnosis of eye disease. However, the eye presents a particular challenge for drug delivery due to the various barrier mechanisms that have evolved to protect the delicate ocular tissues from noxious substances. These barriers often make it difficult to maintain a sufficiently high drug concentration to achieve the desired therapeutic effect. However, using high drug concentrations to overcome these barriers needs to be balanced with the susceptibility of the eye to drug toxicity and the risk of systemic adverse effects. The aim of this module is to provide an overview of the general principles of pharmacology and specifically address the factors involved in ocular pharmacokinetics.