Lidocaine

BRAND NAMES:
Synera -  Synera contains two local anesthetics, lidocaine and tetracaine. It is applied to the skin to alleviate pain before inserting a needle and removing small skin samples for testing.
Zingo – It contains Lidocaine hydrochloride monohydrate powder used for intradermal injection which contains 0.5mg of sterile lidocaine hydrochloride monohydrate.
Akten – Lidocaine hydrochloride is the main active ingredient in Akten a topical eye anesthetic used as acular surface anesthesia during ophthalmologic procedures.
Xylocaine MPF sterile solution – Xylocaine MPF is a sterile Lidocaine HCL solution used to numb an area of your body and help reduce pain or discomfort caused by medical procedures.
Lignospan forte – The main active ingredients present in lignospan forte are lidocaine hydrochloride and epinephrine which are used as local anesthesis for dental procedures.
MECHANISM OF ACTION:
Lidocaine acts at sodium ion channels on the internal surface of nerve cell membranes. The uncharged form of lidocaine diffuses through neural sheaths into the axoplasm before ionizing by combining hydrogen ions. The resulting cation binds reversibly to sodium channels from the inside, locking them in the open state and preventing nerve depolarization. Lidocaine’s efficacy is reduced at the inflammation site; this may be due to acidosis reducing the proportion of neutral lidocaine molecules and faster reductions in local lidocaine concentration due to increased blood flow. Lidocaine functions as an NMDA antagonist and offers potential benefits for patients with difficult-to-control pain, such as mixed nociceptive neuropathic pain and central sensitization.
PHARMACOKINETICS:
Absorption: Lidocaine is well absorbed throughout the gastrointestinal tract, but its oral bioavailability is only about 35% due to a high level of first-pass metabolism. Lidocaine is rapidly absorbed after injection into tissues, and the rate of absorption is influenced by vascularity as well as the presence of tissue and fat capable of binding lidocaine in specific tissues.
Distribution: The volume of lidocaine distribution is 0.7 to 1.5 L/kg.
Metabolism: Lidocaine is metabolized mainly by the liver. The hepatic enzymes CYP1A2 and CYP3A4 metabolize lidocaine into active and inactive molecules.
Excretion: Approximately 90% of the drug is excreted in urine. Renal clearance is inversely related to protein binding affinity and urine pH.
PHARMACODYNAMICS:
The rapid onset of action occurs approximately one minute after intravenous and fifteen minutes after intramuscular injection. The administered lidocaine then spreads rapidly through the surrounding tissues, with the anesthetic effect lasting approximately ten to twenty minutes when given intravenously and sixty to ninety minutes after intramuscular injection. It appears that lidocaine's efficacy may be reduced in the presence of inflammation.
DOSAGE AND ADMINISTRATION:
Lidocaine is available in various forms, such as solutions, aqueous gels, and ointments of different strengths. Sometimes it is used as local anesthesia by combining with epinephrine or any other local anesthetic drugs. In the treatment of 
•    Solutions of 1% to 2% are used for epidural anesthesia and regional nerve block and are available in intravenous preparations for antiarrhythmic use.
Solutions of 0.25% to 0.5% are used for intravenous regional anesthesia or infiltration into subcutaneous tissue. Solutions of 0.05% to 0.1% can be injected subcutaneously in large volumes to provide tumescent local anesthesia.
•    This results in swelling and firmness of the site, which may benefit particular surgical procedures. 
•    Ointments typically contain 5% lidocaine mixed with hydrocortisone and re-applied topically to other mucous membranes, such as the skin or the rectum.
•    Aqueous gel of 1% to 2% typically contains an antiseptic and is used to topicalize and lubricate the urethra before procedures such as Foley catheterization.
•    A solution of 4% is used for topical anesthesia of the mucous membranes of the airway, including the mouth, pharynx, and respiratory tract. 10% solution is applied for airway anesthesia using a metered dose atomizer.
•    An eutectic mixture of lidocaine and prilocaine combines the local anesthetics which effectively penetrates the skin to provide local cutaneous anesthesia and is commonly used to avoid pain associated with needle punctures. And when lidocaine is mixed with epinephrine used in dentistry.
The dose of lidocaine used to obtund airway reflexes is 1 to 2 mg/kg, administered 2 to 5 minutes before intubation. Patients undergoing open and laparoscopic abdominal surgeries receive an intraoperative infusion of 2 mg/kg/h. For cardiac dysrhythmias, an initial dose of 1 to 1.5 mg/kg is administered intravenously, followed by an infusion. The recommended dose for adjuvant intravenous treatment of acute pain is 1.5 mg/kg over 10 minutes, followed by an infusion of 1.5 mg/kg/h for no more than 24 hours.
CONTRAINDICATIONS:
Lidocaine is contraindicated for patients with a known severe adverse reaction.
DRUG INTERACTIONS:
If the doctor prescribes this lidocaine drug, then there is a need to discuss the medications that have been taken previously in treating another disease. Some drugs interact with lidocaine, resulting in decreasing the working condition of lidocaine and also showing some toxic effects. Below are some medications mentioned that should be avoided with lidocaine unless the doctor prescribes it.
•    Lomitapide
•    Axitinib
•    Dofetilide
•    ELIGLUSTAT
•    Cobimetinib
•    Bupivcaine liposome
•    Ivacator
•    Fluvoxamine
•    Eliglustat
•    Fosamprenavir
•    Fentanyl transdermal, iontophretic transdermal system
•    Fentanyl intranasal, transmucosal
•    Fibanserin
•    Fentanyl
•    Pimozide
•    Pomalidomide
ADVERSE EFFECTS:
•    Nausea
•    Vomiting
•    Skin irritation
•    Redness at the injection site
•    Swelling
•    Dizziness
•    Constipation
•    Numbness and tingling
•    Tremor
•    Cardiac arrest
•    Hypertension
•    Anaphylaxis
•    Malignant hyperthermia
•    Methemoglobinemia
TOXICITY:
Taking an overdose can lead to some toxic effects. Below are the symptoms of toxicity 
•    CNS depression
•    Agitation
•    Tinnitus
•    Blurred vision
•    Paranoia
•    Muscle twitches
•    Seizures.

STORAGE: 
Lidocaine can be stored at room temperature 20 to 25 °C (68 to 77 °F).