Tramadol (INN) is an atypical novel narcotic analgesic which is a centrally acting analgesic, used for treating moderate to severe pain. It is a synthetic agent, as a 4-phenyl-piperidine analogue of codeine, and appears to have actions on the GABAergic, noradrenergic and serotonergic systems. Tramadol was developed by the German pharmaceutical company Grünenthal GmbH and marketed under the trade name Tramal. Grünenthal has also cross licensed the drug to many other pharmaceutical companies that market it under various names. Tramadol is usually marketed as the hydrochloride salt (tramadol hydrochloride) and is available in both injectable (intravenous and/or intramuscular) and oral preparations. It is also available in conjunction with paracetamol (acetaminophen). Tramadol is approximately 10% as potent as morphine, when given by the IV/IM route. Oral doses range from 50–400 mg daily, with up to 600 mg daily when given IV/IM. The formulation containing APAP contains 37.5 mg of tramadol and 325 mg of paracetamol, intended for oral administration with a common dosing recommendation of one or two tabs every four to six hours. Tramadol is not considered a controlled substance in many countries (the U.S. and Australia, among others), and is available with a normal prescription. Tramadol is also available over-the-counter without prescription in a few countries. It is often argued that tramadol isn't considered a opioid, when in fact, it is. It is often called a novel analgesic, or a quasi-narcotic analgesic, because it also has a SSRI effect.