Using our advice
Dental anaesthetic cartridges can include a LA and vasoconstrictor. Interactions with each component must be considered. Drugs with a BNF monograph have been considered in preparing this page if an interaction is described in the BNF or Summary of Product Characteristics (SPC). SPCs are accessible via the eMC or MHRA websites.
When our advice refers to a number of cartridges, it applies to cartridges of any volume and concentration of adrenaline available in the UK. Due to the small volumes involved, differences between cartridges are not expected to be clinically relevant.
General considerations
Before considering a specific interaction, ensure you are familiar with our general guidance:
Considering interactions with local anaesthetics in dentistry
Specific recommendations
Most interactions related to LA components of dental LA cartridges are not expected to be clinically relevant when used as intended within their licensed dosages. Therefore, no dose adjustment will be needed. Dental LA cartridges containing adrenaline may require additional consideration.
Searching for interactions
The quick links in the content navigation bar allow you to access different therapeutic classes quickly. You can also use your device or browser’s search function to find a specific medication.
Interactions with LA component
Clinically significant interactions between LA components and other drugs are unlikely. If articaine, lidocaine, mepivacaine or prilocaine-containing LA cartridges are used as licensed for dentistry, no action is needed.
Interactions with felypressin
Clinically significant interactions between felypressin and other drugs are unlikely. If felypressin-containing LA cartridges are used as licensed for dentistry, no action is needed.
Interactions with adrenaline
Adrenaline is the only LA cartridge component where clinically relevant interactions may be expected, even when used as licensed for dentistry.
Apraclonidine
No action needed
The alpha-stimulating action of apraclonidine may be additive to adrenaline, leading to increased vasoconstriction and hypertension.
A clinically significant interaction is unlikely if adrenaline-containing dental LA cartridges are used as licensed.
Antiarrhythmics
No action needed
Antiarrhythmics include adenosine, amiodarone, disopyramide, dronedarone, flecainide, mexiletine, propafenone, quinidine and vernakalant.
A clinically significant interaction is unlikely if adrenaline-containing dental LA cartridges are used as licensed.
Butyrophenone antipsychotics
Use a maximum of two adrenaline-containing anaesthetic cartridges
Butyrophenone antipsychotics include benperidol, droperidol and haloperidol.
Butyrophenone antipsychotics may block alpha receptors, reducing adrenaline’s vasoconstrictive effect and potentially leading to increased hypotension.
In general dentistry, any potential interaction is not expected to be clinically significant. However, a reduced dose of adrenaline is advised as a precaution.
Catechol-O-methyl transferase inhibitors
Use a maximum of two adrenaline-containing anaesthetic cartridges
Catechol-O-methyl transferase (COMT) inhibitors include entacapone, opicapone and tolcapone.
COMT inhibitors prevent inactivation of adrenaline, potentially enhancing its vasoconstrictive and cardiostimulatory effects.
In general dentistry, any potential interaction is not expected to be clinically significant. However, a reduced dose of adrenaline is advised as a precaution.
Cocaine
Do not administer adrenaline-containing anaesthetic cartridges for at least 24 hours after last use
The sympathomimetic action of cocaine may be additive with adrenaline and increase risk of hypertension, arrhythmias and cardiac events.
Ergotamine
No action needed
The vasoconstrictive effect of the ergot alkaloid ergotamine may be additive to adrenaline and increase risk of hypertension and cardiac events.
A clinically significant interaction is unlikely if adrenaline-containing dental LA cartridges are used as licensed.
Foslevodopa
No action needed
Adrenaline might increase cardiovascular adverse effects of foslevodopa’s active metabolite.
A clinically significant interaction is unlikely if adrenaline-containing dental LA cartridges are used as licensed.
Monoamine oxidase inhibitor
No action needed
Monoamine oxidase inhibitors (MAOIs) include isocarboxazid, linezolid, phenelzine, rasagiline, safinamide, selegiline and tranylcypromine. Some MAOIs are used for Parkinson’s symptoms, and others as antidepressants.
Historically, it was thought the combination of adrenaline and MAOIs could lead to severe hypertension in the dental setting.
However, research now shows a clinically significant interaction is unlikely if adrenaline-containing dental LA cartridges are used as licensed.
Specific contraindications
Scandonest Special and Orabloc contraindicate use with MAOIs, while BNF and other brands do not, suggesting this is overcautious. Prescribing a contraindicated product alters professional responsibility and liability. Choose a product without a contraindication if available.
Non-selective beta-blockers
Use a maximum of two adrenaline-containing anaesthetic cartridges
Non-selective beta-blockers include nadolol, pindolol, propranolol, sotalol and timolol.
Non-selective beta-blockers inhibit adrenaline’s beta-controlled peripheral vasodilatory effects. This allows adrenaline’s alpha-stimulating action to function unopposed, effectively acting as a pure vasoconstrictor. This can lead to increased hypertension and a higher risk of cardiac events.
Adrenaline interactions are not routinely expected when used in general dental settings. However, as interactions could potentially have serious implications, a reduced dose of adrenaline is advised as a precaution.
Specific contraindications
Orabloc contraindicates use with non-selective beta-blockers, but BNF and other brands do not, suggesting this is overcautious. Prescribing a contraindicated product alters professional responsibility and liability. Choose a product without a contraindication if available.
Oral antidiabetics
No action needed
The Orabloc SPC warns adrenaline may inhibit insulin release in the pancreas, reducing effects of drugs that exert their action in this way. This includes repaglinide and sulfonylureas gliclazide, glimepiride, glipizide and tolbutamide.
The BNF and other SPCs do not state this interaction, suggesting this is overcautious.
A clinically significant interaction is unlikely if adrenaline-containing dental LA cartridges are used as licensed.
Ozanimod
No action needed
There may be an increased risk of hypertension if adrenaline is administered alongside ozanimod.
A clinically significant interaction is unlikely if adrenaline-containing dental LA cartridges are used as licensed.
Phenothiazine antipsychotics
Use a maximum of two adrenaline-containing anaesthetic cartridges
Phenothiazines include chlorpromazine, prochlorperazine and trifluoperazine.
Phenothiazines block alpha receptors, reducing adrenaline’s vasoconstrictive effect and potentially increasing hypotension.
In general dentistry, any potential interaction is not expected to be clinically significant. However, a reduced dose of adrenaline is advised as a precaution.
Selective beta-blockers
No action needed
Selective beta-blockers include acebutolol, atenolol, betaxolol, bisoprolol, carvedilol, celiprolol, esmolol, labetalol, landiolol, levobunolol, metoprolol and nebivolol.
Selective beta-blockers do not inhibit adrenaline’s peripheral vasodilatory effects, so they do not carry the same risk of causing increased hypertension when used alongside adrenaline as non-selective beta-blockers.
A clinically significant interaction is unlikely if adrenaline-containing dental LA cartridges are used as licensed.
Selective noradrenaline reuptake inhibitors
Use a maximum of two adrenaline-containing anaesthetic cartridges
Selective noradrenaline reuptake inhibitors (SNRIs) include duloxetine and venlafaxine. Bupropion also blocks reuptake of noradrenaline.
SNRIs (and bupropion) increase noradrenaline levels, potentially enhancing vasoconstrictive and cardiostimulatory effects of adrenaline.
In general dentistry, any potential interaction is not expected to be clinically significant. However, a reduced dose of adrenaline is advised as a precaution.
Sympathomimetics
No action needed
The SPCs of dental LA cartridges mention a wide variety of medications that could potentially interact due to their sympathomimetic effects.
These include the amphetamines, dexamfetamine and lisdexamfetamine, antihistamines, chlorphenamine and diphenhydramine, decongestants, oxymetazoline, phenylephrine and pseudoephedrine, as well as levothyroxine, methyldopa and vasopressin.
A clinically significant interaction is unlikely if adrenaline-containing dental LA cartridges are used as licensed.
Tricyclic antidepressants
Use a maximum of two adrenaline-containing anaesthetic cartridges
Tricyclic antidepressants (TCAs) include amitriptyline, clomipramine, dosulepin, doxepin, imipramine, lofepramine, nortriptyline and trimipramine.
TCAs slow adrenaline reuptake, increasing blood levels and potentially enhancing vasoconstrictive and cardiostimulatory effects.
In general dentistry, any potential interaction is not expected to be clinically significant. However, a reduced dose of adrenaline is advised as a precaution.
Specific contraindications
Scandonest Special and Orabloc contraindicate use with TCAs. BNF and other brands do not, suggesting this is overcautious. Prescribing a contraindicated product alters professional responsibility and liability. Choose a product without a contraindication if available.