Tag Archives: toxicity

Lidocaine Info Important For My Surgical Practice – Maximums and Toxicity

lidocaine picture from drugs.com

Lidocaine

  • Also known as Xylocaine and sometimes Lignocaine
  • Local Anesthetic
  • Antiarrhythmic drug – for ventricular arrhythmias (but Amiodarone is mostly used for this)
  • The first Amino-Amide local anesthetic
  • First marketed in 1949
  • Alters signal conduction in neurons by blocking the fast voltage gated sodium channels in the neuronal cell membrane.  Thus prevents depolarization of the postsynaptic neuron.

Esters and Amide local anesthetics – way to remember which

  • Esters have only one “i” in the name: Procaine, Cocaine
  • Amides have over two “i”s in the name:  Lidocaine, Bupivicaine, Prilocaine.

Contraindications to using Lidocaine

  • Porphyria – rare inherited or aquired disorders of enzymes which produce porphyrins and heme resulting in neurological complications (abdominal pain, vomiting, neuropathy)  or skin problems.
  • Heme is one the best known porphyrin the pigment in red blood cells and cofactor of the protein hemoglobin.
  • Porphyrin means purple

Lidocaine overdose

  • can occur with topical creams
  • Treatment with IV lipid emulsions can reverse the effects of lidocaine toxicity.

Adverse Effects

  • Rare
  • Allergic reactions rare.
  • CNS (central nervous system) and cardiovascular effects
  • CNS at lower doses, cardiac at higher doses
  • CNS: nervousness, tingling around mouth, tinnitus, tremor, dizziness, blurred vision, seizures, depression, loss of consciousness
  • Cardiovascular effects: hypotension, bradycardia, arrhythmias

Insensitivity to Lidocaine

  • Genetic
  • Exists in some patients with ADHD and Ehlers-Danlos syndrome

Lidocaine Safety and Toxic doses

  • Particular care in calculating maximum safe dose for young children
  • Peak blood levels of lidocaine usually occur 10-25 minutes after injection – the point at which toxic effects are likely to be seen.
  • Maximum safe dose of lidocaine without vasoconstrictor (ie. epinephrine) is 3-4.5 mg/kg (duration of action 1 hour).  No more than 300 mg (30 cc’s of 1% Lidocaine) at once.
  • Maximum safe dose of lidocaine with vasoconstrictor is 5-7 mg/kg (duration of action 2-6 hours)

How to calculate Maximum safe doseage of Lidocaine

  • You need to know that 1% Lidocaine solution is 10 mg/mL
  • Example Calculation for a 70 Kg man:  Lido 1% with Epi:  keep under 7 mg/Kg.  7×70 = 490 mg for 70 kg man.  Divide 490 mg by 10 mg/ML = 49 ml.

How is this important to our Plastic Surgical and Acupuncture practice?

  • We use lidocaine in plastic surgical procedures – topical and subcutaneous – for removal of moles, injection of fillers such as Juvederm, and sometimes for Botox.
  • I also use injected  lidocaine as part of some trigger point deactivation practices in acupuncture.

Cosmetic Procedures at Surgical Artistry which may use Lidocaine

  • Liposuction – tumescent lidocaine
  • Mole removal – injected subcutaneous local lidocaine
  • Fillers – Juvederm – some formulations have lidocaine within the product
  • Fillers and Botox – sometimes we use topical lidocaine
  • Face Veins – sometimes we use topical lidocaine
  • Minor office surgeries – we use injected lidocaine in the subcutaneous level