Lidocaine is an amide local anesthetic indicated for regional anesthesia which blocks voltage gated sodium channels.
Hi everyone today in this video we are going to discuss about lidocaine what is this drug lidocaine the suffix cane indicates this drug acts as local anesthetic this lidocaine can also be called with another name lignocaine and it is well known by the brand name xylocaine all these are the synonyms for lidocaine and this lidocaine is a mi type localistic
Localities are of two types either mi derivatives or ester derivatives so lidocaine is a mi derivative because of my link case this drug is more stable as well as less allergic compared with the extra derivatives but at the same time this drug is having more systemic toxicity so if this drug is given accidentally into the systemic circulation otherwise when it
Is locally applied if it is significantly absorbed into the systemic circulation in such cases we can see the systemic toxicity produced by the strike that’s why lidocaine is intended for local action only and sometimes in order to increase its local action this lidocaine is combined with vasoconstrictors such as epinephrine lidocaine can also be used as a class
1b anti arithmetic and it can be used to terminate ventricular tachycardia but here in this video we are going to see how this lidocaine acts as low classic what are the important precautions side effects dosage forms all these things we will discuss in this video so lidocaine as a localistic it can be given by injection to produce epidural as well as lumbar
Anesthesia otherwise it can also be given as a perineural anesthesia where the neural block is going to be produced by lidocaine and it can be given by percutaneous injection where it acts by infiltration to reduce the sensitization and neuronal transmission this drug can also be used to control the nociception in the patients with neuropathic pain where it
Locally reduce the pain sensation and apart from these clinical uses this drug can also be topically applied on the mucous membrane as well as on the skin to produce the local anesthesia now that is the chemical nature of this diet so this is the structure of lidocaine and here we can simply observe an amylink case so this is the amide which is attached with
The two carbon chain so let us give the numbering this is one and this is two so two carbon chain is there which is nothing but histamine so lidocaine is a semi derivative on the second portion it is having an amine which is dye substituted which is nothing but two dash diethyl amino and on the nitrogen of amide phenyl ring is attached so n-phenyl and this phenyl
Is having methyl groups at both of the ortho portions so 2 6 dimethyl that is a complete name of lidocaine now let us see how this drug acts lidocaine acts as local asterisk by inhibiting the neuronal transmission through the axon particularly it blocks the voltage-gated sodium channels thereby inhibits axonal conduction so on the axon sodium channels can exist
In three states they can be exist as closed state where they are not allowing the sodium ions otherwise they can exist as open state where the getting mechanism is open so that sodium can enter through this channel otherwise they can present as refractive state where the inner gating mechanism is somewhat closed so it is in the intermediate state between open
As well as closed states now the sodium ions can enter through this open state sodium channels so that they can produce depolarization of the axon which produce the neuronal transmission here lidocaine can block this neuronal transmission now lidocaine can block the open state ion channels so you can block directly the open state ion channels and this type of
Pathway is called hydrophilic pathway otherwise the lidocaine can cross the lipophilic membrane and it can enter into the cytoplasm now within the cytoplasm this drug is going to be protonated so that it is hydrophilic in nature now it can block the inner side of this open state sodium channels so this type of pathway is called hydrophobic pathway in this way
Lidocaine can act by both hydrophilic as well as hydrophobic pathway and by both of these pathways lidocaine can inhibit the sodium channel activity resulting in the decreased neuronal conduction what are the precautions one of the important precautions of lidocaine is that this drug can produce some local reactions so when this lidocaine is going to be applied
On the skin or mucous membrane it can produce some irritation burning sensation some bruising edema as well as erythema can be observed that’s why this drug should be used at a low dose for topical purpose in order to minimize the local reactions similarly when this drug is applied to the broken skin it can produce some irritation that’s why lidocaine should
Be applied for intact skin in case of broken skin when this lilocaine is going to be applied it can produce some local irritation as well as some of the lidocaine molecules can enter into the systemic circulation through this broken skin where they increase the systemic absorption leading to some systemic toxicity since this drug is intended for local action it
Should not be applied on the skin areas which are directly exposed to the circulatory system to minimize this systemic absorption similarly this drug can produce myth hemoglobinemia particularly this condition is observed in the patients who are having glucose 6-phosphate dehydrogenase deficiency glucose 6-phosphate dehydrogenase is one of the important enzyme
Required for production of nadph this nadph can activate the glutathione system so that it can reduce the oxidative stress so the patients with decreased levels of glucose 6-phosphate dehydrogenase the oxidative stress is increased resulting in the destruction of rbc cells so this damage to the rbc may result in the decreased auxin carrying capacity resulting
In few of the symptoms such as blue discoloration seizures and arrhythmias can be produced that’s why this structure be carefully given the patients who are having the risk of myth hemoglobinemia in such patients this drug should be carefully given just to have seen that lidocaine is intended for local anesthesia but when this drug is undergoing systemic
Absorption it can produce some systemic toxicity so that it can affect the central nervous system leading to various symptoms such as dizziness lightheadedness some confusion drowsiness some tinnitus can also be observed and blurred vision even at high dose it can produce conversions in the patients that’s why any accidental consumption of lidocaine by
Systemic root otherwise any significant seismic absorption when it is applied by local root in both of the cases it can produce some systemic toxicity affecting the central nervous system similarly this systemic absorption can also affect the heart resulting in the bradycardia some hypotension and even at high dose it can produce some cardiac arrest in the
Patients similarly when this drug is in contact with i it can produce some local irritation resulting in the redness of i and it can also produce some hypersensitive reactions but these hypersensitive reactions are somewhat less compared with the power derivatives we have the power derivatives such as benzocaine which is having a more allergic response compared to
The lidocaine what are the side effects the important side effects of lidocaine are mainly related with its local action it can produce some local irritation erythema flushing redness of the skin pruritus edema can be produced and it can also affect the cns resulting in nervousness lightheadedness tinnitus some budging noise in the ear blurred vision bradycardia
Any hypersensitive reactions like angioedema and hypotension can be observed with this lidocaine how it is given lidocaine is available in different dosage forms it is available as solution cream gel even spray patches in all these doses forms it is available even it is available as powder and in many of the formulations it is combined with other drugs such as
Epinephrine otherwise it is combined with other drugs such as metronidazole to produce anesthesia in the world cavity but as the solution this drug is given by iv root to produce the epidural anesthesia perineural anesthesia percutaneous anesthesia and in other doses forms it is given by topical root to produce local anesthesia so lidocaine can produce either
Local or regional anesthesia whether it can be given by iv root or it can be topically applied this truck mainly blocks the voltage-gated sodium channels thereby can reduce the neural transmission but when this drug is accidentally consumed by systemic root otherwise when it is more absorbed into the systemic circulation it can produce some systemic toxicity
Mainly affecting the cns to produce lightheadedness dizziness drowsiness tinnitus at a high dose it can produce convulsions similarly it can affect the heart resulting in bradycardia hypotension even cardiac arrest and as a low plastic it can produce some local irritation resulting in skin irritation flushing edema pruritus and on the broken skin when it is
Applied it can produce some local irritation and it increase the risk of systemic absorption so lidocaine is a mi derivative which is having some less hypersensitive reactions compared with the power derivatives but this drug is having more systemic toxicity so it is intended only for local purpose so that’s about this track lidocaine hope you have enjoyed this
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Transcribed from video
Lidocaine as Local Anesthetic By egpat