The effectiveness of a drug can be greatly affected by the route of its administration. It is now possible to better control the pharmacokinetics, pharmacodynamics, toxicity, immunogenicity and effectiveness of drugs by creating a variety of Drug Delivery Systems (DDSs). Route of administration is Via many different pathways, drugs can be administered into the body. In general, these routes are categorised by their "initial point" the position where the medication is administered. By swallowing, inhalation, absorption through the skin, or intravenous injection, drugs may be taken in a number of ways. Each route provides its own benefits and drawbacks. Side effects often occur, depending on the drug, the way it is administered, and how our bodies react. Such side effects can differ greatly in form and severity from individual to individual. An oral medicine for seasonal allergies, for instance, may cause unwanted drowsiness or an upset stomach. A common approach to minimise adverse effects and drug toxicity while optimising the effectiveness of a medication is to prescribe medications locally rather than systemically (affecting the entire body). Any of the systemic side effects of these medications may be prevented by a topical (used on the skin) antibacterial ointment for localised infection or cortisone injection into a sore joint.