Most Drugs are taken orally. Dosage interval may be inconvenient. Some drugs are partly destroyed or neutralized in the stomach, intestine or liver before reaching the blood stream. Accordingly a higher dose is needed to ensure efficiency, which in turn may increase the risk of the side effects.

   To counter these limitations and to improve patient compliance, drug companies have introduced patches. Unlike oral medication, drug patches release the active compounds directly into the blood. By avoiding the gastrointestinal system, the drug is less likely to cause
nausea and other side effects. The patch administers a constant level of the drug, avoiding the peaks and troughs in drug levels obtained from oral drugs. By wearing a patch, patient do not need to worry about forgetting, or waking up to take a pill.

   Patches also avoid the mess and inconvenience of topical creams and lotions. So often cream and lotions rub off before they are effective.