Introduction to Pharmacology and Routes of Drug Administration and Absorption of Drugs1.1 Introduction to Pharmacology1.2 Drug Nomenclature1.3 Introduction to drug administration and absorption of drugs1.4 Routes of drug administration1.5 Oral administration, absorption from gastrointestinal tract, and first pass liver metabolism1.6 Rectal1.7 Sublingual1.8 Injection1.8.1 Intravenous1.8.2 Intra-arterial1.8.3 Subcutaneous1.8.4 Intramuscular1.8.5 Intrathecal1.8.6 Epidural1.9 Topical1.9.1 Skin1.9.2 Nasal mucosa1.9.3 Eye 1.9.4 Vaginal1.10 Pulmonary – Inhalation1.11 Intraosseus Summary This eChapter has an introduction to pharmacology and drug nomenclature followed by a detailed discussion of routes of administration starting with oral administration (with absorption from the gastrointestinal tract, and first pass liver metabolism). This is followed by a discussion of rectal, sublingual and injection routes of administration (intravenous, intra-arterial, subcutaneous, intramuscular, intrathecal and epidural). Then the topical, pulmonary and intraosseus routes of administration are considered.