Drug interactions with LA Flashcards

1
Q

How can practioners minimise the risk of drug interactions with LA?

A
  • using an aspirating syringe; this reduces the likelihood of LA being administered directly into a blood vessel
  • adhering to dosing recommendations in product literature
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2
Q

What are the most commonly used amide LAs for dental procedures?

A
  • lidocaine
  • prilocaine
  • articaine
  • mepivacaine
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3
Q

Where does evidence of potential interactions with LA dental preparations come from?

A
  • they came from anecdotal case reports
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4
Q

When are the drug interactions with LA, reported by the BNF, thought to be relevant?

A

when LA/ vasoconstrictors are used at high doses for specific indications other than dental anaesthesia

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5
Q

State other clinical uses of lidocaine

A
  • as treatment for arrhythmia - doses up to 1750 mg intravenously for over 24 hours
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6
Q

Outline the dose of adrenaline used for anaphylaxis

A

500 mg IM

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7
Q

Outline the dose of adrenaline used for cardiac arrest

A

1000 mg IV

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8
Q

How much lidocaine (in mg) does a 2.2ml cartridge of 2% lidocaine in 1:80 000 solution contain?

A

44mg

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9
Q

How much adrenaline (in mg) does a 2.2ml cartridge of 2% lidocaine in 1:80 000 solution contain?

A

27.5 mg

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10
Q

How much lidocaine (in mg) does a 1.8ml cartridge of 2% lidocaine in 1:80 000 solution contain?

A

36mg

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11
Q

How much adrenaline (in mg) does a 1.8ml cartridge of 2% lidocaine in 1:80 000 solution contain?

A

22.5mg

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12
Q

What is the theoretical consequence of using/delivering more than one local anaesthetic agent (using a combination of local anaesthetic agents)?

A
  • increased risk of myocardial depression
  • increased risk of ventricular arrhythmia
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13
Q

What is the consequence of using anti-arrhythmic doses of lidocaine with other anti-arrhythmic agents?

A
  • may result in myocardial depression
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14
Q

What is the consequence of using prilocaine with anti-arrhythmic agents?

A

myocardial depression

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15
Q

What advice is given for the use of articaine for patients receiving anti-arrhythmic agents?

A

manufacture advises a caution when administering articaine in such cases

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16
Q

Outline a relevant interaction between lidocaine and antibacterial drugs. State what antibacterials this interaction applies to

A
  • increased risk of ventricular arrhythmia
  • quinupristin
  • dalfopristin
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17
Q

State the relevant anti-bacterials with potential interaction with LAs

A
  • quinupristin
  • dalfopristin
  • sulphonamides
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18
Q

Outline the relevant interaction between prilocaine and antibacterials. State the antibacterial drug that this applies to

A
  • increased risk of methaemoglobinaemia
  • sulphonamindes e.g. co-trimoxazole
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19
Q

Outline the relevant interaction between lidocaine and antipsychotic agents

A
  • lidocaine at high doses can increase the risk of ventricular arrhythmia
  • prolonged QT interval
20
Q

State the relevant anti-viral agents with potential interactions with LA agents

A
  • fosamprenavir
  • darunavir
  • atazanavir
  • lopinavir
21
Q

Outline the potential drug interaction between lidocaine and antiviral drugs

A

antiviral agents appear to increase plasma concentration of lidocaine and potentially increase cardiotoxicity

22
Q

Outline the drug interaction between lidocaine and betablockers

A
  • high dose lidocaine with beta blockers can cause myocardial depression
  • lidocaine clearance is reduced by propanolol; increases toxicity risk when lidocaine is given at high doses
23
Q

What is the effect of diuretics on lidocaine?

A
  • action of lidocaine is antagonised by hypokalaemia caused by acetazolamide, loop diuretics or thiazides and related diuretics
24
Q

What is the interaction of lidocaine and 5HT3 antagonists such as dolasetron?

A
  • increased risk of ventricular arrhythmia
25
Q

Outline the drug interaction between lidocaine and ulcer healing drugs such as cimetidine

A
  • increased plasma concentrations of lidocaine; increased risk of toxicity when high doses of lidocaine are used
  • this effect is not seen with other ulcer healing drugs
26
Q

Outline the drug interaction between lidocaine and sedatives such as midazolam

A
  • midazolam has been reported to cause a modest reduction in serum lidocaine levels but not mepivacaine levels
27
Q

Outline the nature of the drug interaction between local anaesthetic agents and TCAs

A
  • increaed risk of hypertension and arrhtymias is high doses of adrenaline are given
28
Q

What is the clinically relevant dose of local anaesthetics if they are given to a patient on TCAs?

A

None if </= 2 cartridges of 1: 80 000 adrenaline containing solution are used

29
Q

What is the clinically relevant dose of local anaesthetics if they are given to a patient on non-cardio-selective beta-blockers?
State the non-cardio-selective beta blockers this applies to

A

None if </= 2 cartridges of a 1: 80 000 adrenaline containing solution is used

if more than 2 cartridges are required then an adrenaline free solution should be used

  • propanolol
  • nadolol
  • timolol
  • sotalol
30
Q

Outline the nature of the reaction between beta-blockers and LA agents

A
  • increased risk of severe hypertension
  • bradycardia when adrenaline is given with non-cardioselective beta-blocker
31
Q

What is the guidance for LA use with patients who abuse cocaine ?

A

avoid using LA containing adrenaline unless it is certain they have not used cocaine for 24 hours

32
Q

What is the nature of the interaction between LA agents and cocaine?

A

cocaine and adrenaline have sympathomimetic effects

increase the risk of arrhythmias

33
Q

Outline the potential interaction between LA and clonidine

A

possible risk of hypertension when adrenaline is given with clonidine

34
Q

What is the clinically relevant dose of LA agents if administered to a patient on diuretics?

A

none if </= 2 cartridges of 1: 80 000 adrenaline containing solution are used

35
Q

What is the guidance for the use of dopaminergics such as entacapone and LA ?

A
  • no adverse reactions with entacapone have been reported in the dental setting
  • however it is a new drug an caution is vasoconstrictor dosing is required
36
Q

Outline the potential nature of the reaction between LA and entacapone

A

serum levels and therefore effects of adrenaline are possibly enhanced by entacapone

37
Q

The interaction between sympathomimetics and rasagiline (dopaminergic) are not clinically relevant in dentistry. True or false

What is the guidance for use of sympathomimmetics and rasagiline

A

True

avoid concomitant use of sympathomimetis with rasagiline

sympathmimetics referred to here are those that are present in decongestant medication containing ephedrine or pseudoephedrine

38
Q

What is the nature of the reaction between LA agents and MAOI antidepressants?

A

co-administration of higher doses of adrenaline and MAOI antidepressants may produce hypotension or hypertension

39
Q

What is the nature of the interaction between higher doses of adrenaline and SNRIs/phenothiazines?
Give examples of SNRI implicated in this

A

prolonged hypotension or hypertension

  • duloxetine
  • venlafaxine
40
Q

What is the clinically relevant dose of LA agents when considering its use with SNRIs or phenothiazines

A

none if doses of adrenaline do not exceed 50 mg / </= 2 cartridges of a 1:80 000 adrenaline containing solution

41
Q

Warnings about the potential interaction between SNRIs/phenothiazines and LA only appear in product literature for …

A

Lignospan Special

42
Q

Of the available vasoconstrictors (felypressin and adrenaline) only ________ is listed as interacting with other drugs

A

adrenline

43
Q

Although intraligamentary injection can result in rapid absorption into systemic circulation, why are LA levels unlikely to result in clinically significant drug interactions?

A

volumes used for intra-ligamentary injections are very small (0.2-0.5 ml; 2.5-6.25 mg of adrenaline respectively)

44
Q

Intra-osseous injection can lead to rapid absorption into systemic circulation. True or false

A

True

45
Q

Infiltration and regional block anaesthesia are not associated with significant systemic absorption. True or false

A

True