MEGX has a longer half-life than lidocaine, but also is a less potent sodium channel blocker. The volume of distribution is 1.1 L/kg to 2.1 L/kg, but congestive heart failure can decrease it. About 60% to 80% circulates bound to the protein alpha1 acid glycoprotein. The oral bioavailability is 35% and the topical bioavailability is 3%. The elimination half-life of lidocaine is biphasic and around 90 min to 120 min in most patients. This may be prolonged in patients with hepatic impairment (average 343 min) or congestive heart failure (average 136 min). Lidocaine is excreted in the urine (90% as metabolites and 10% as unchanged drug). History
Lidocaine, the first amino amide–type local anesthetic, was first synthesized under the name xylocaine by Swedish chemist Nils Löfgren in 1943. His colleague Bengt Lundqvist performed the first injection anesthesia experiments on himself. It was first marketed in 1949. Society and culture
Dosage forms
Lidocaine, usually in the form of its hydrochloride salt, is available in various forms including many topical formulations and solutions for injection or infusion. It is also available as a transdermal patch, which is applied directly to the skin. Names
Lidocaine is the International Nonproprietary Name (INN), British Approved Name (BAN), and Australian Approved Name (AAN), while lignocaine is the former BAN and AAN. Both the old and new names will be displayed on the product label in Australia until at least 2023.Xylocaine is a brand name. Recreational use
As of 2021, lidocaine is not listed by the World Anti-Doping Agency as a substance whose use is banned in sport.
Calcific tendinitis is a common condition where calcium deposits form in a tendon, sometimes causing pain at the affected site. Deposits can occur in several places in the body, but are by far most common in the rotator cuff of the shoulder. Around 80% of those with deposits experience symptoms, typically chronic pain during certain shoulder movements, or sharp acute pain that worsens at night. Calcific tendinitis is typically diagnosed by physical exam and X-ray imaging. The disease often resolves completely on its own, but is typically treated with non-steroidal anti-inflammatory drugs to relieve pain, rest and physical therapy to promote healing, and in some cases various procedures to breakdown and/or remove the calcium deposits. Adults aged 30–50 are most commonly affected by calcific tendinitis. It is twice as common in women as men, and is not associated with exercise. Calcifications in the rotator cuff were first described by Ernest Codman in 1934. The name, "calcifying tendinitis" was coined by Henry Plenk in 1952. Signs and symptoms
Up to 20% of those with calcific tendinitis have no symptoms. For those with symptoms, the symptoms vary based on the phase of the disease. In the initial "formative phase" when the calcium deposits are being formed, people rarely experience any symptoms. Those that do have symptoms tend to have intermittent shoulder pain, particularly during forward should flexion (i.e. lifting the arm in front of the body). In the "resorptive phase" when the calcium deposit is breaking down, many experience severe acute pain that worsens at night.