Pain management of ICU patients is mostly based on pharmacological intervention. Pharmacological pain management can be done by administration of analgesics (for mild to severe pain), sedation (usually given for relief of pain during a procedure), anesthesia (usually given for relief of pain during a procedure), topical anesthetics (cream, gel, or liquid applied to the skin to numb the area) or other pain relievers. Some people can build up tolerance to sedatives and pain reliever and hence over time doses or types of medication for pain relief must be increased or changed. Also there is fear of addiction to narcotics in some cases. Pain medication may be given in one or more of the several methods like by mouth (orally - in pill form or liquid); with an inhaler; with an injection into a muscle (IM) or under the skin (subcutaneous injection); through a needle in a vein (IV); with a special catheter in a space around the spinal column (epidural); through a patch on the skin; through implanted methods (such as a pump that is implanted in the body); by inserting rectal suppositories.