Local Anesthetic Allergy

Rarely, a patient presents with a history of being allergic to lidocaine or another kind of local anesthetic. Often, the "allergic" reaction described (racing heart, light-headed, dizziness, etc) is more attributable to the epinephrine which is often used in conjunction with the anesthetic; therefore not a true allergy, but a not unexpected possible side effect.

Also, if a true allergy is present, it may not be to the anesthetic itself, but the preservative contained within, typically metabisulfite and/or methylparaben. The exception are single-dose vials which are preservative-free, unless they contain epinephrine. Any local anesthetic containing epinephrine, whether a single-dose or multi-dose vial, has metabisulfite in it. The preservative in the multi-dose vial of lidocaine and other anesthetics typically contain methylparaben. As such, the muti-dose vial of lidocaine with epinephrine would contain both metabisulfite and methylparaben.

In any case, if a true allergy to the anesthetic itself is present, there is the possibility that another type of anesthetic can be used. Why?

There are two different classes of local anesthetics divided into amino esters and amino amides. Chemically, amino amides have an amide link between the intermediate chain and the aromatic end, whereas amino esters have an ester link between the intermediate chain and the aromatic end.

Amino Ester

Amino Amide

There are other differences. Pharmacologically, amino esters are metabolized in the plasma whereas amino amides are metabolized in the liver. Amino esters are unstable in solution, but amino amides are very stable in solution.

Amino esters are also much more likely than amino amides to cause allergic hypersensitivity reactions.

Amino Esters (only one "i" in the spelling of the name):

• Cocaine
• Procaine
• Tetracaine (in the form of cetacaine)*
• Chloroprocaine*
• Benzocaine (in the form of cetacaine)*
• Cetacaine (benzocaine and tetracaine)*
• Propoxycaine

Amino Amides (two "i"'s in the spelling of the name):

• Lidocaine*
• Mepivacaine*
• Prilocaine
• Bupivacaine*
• Ropivacaine*
• Levobupivacaine
• Articaine
• Etidocaine
• Trimecaine
• EMLA (lidocaine/prilocaine)

* is next to those commonly carried in hospitals.

Much appreciate the assistance of Margaret Rowe, PharmD who helped write this blog article.

Source:
Local Anesthetics. Emedicine 4/19/13

Local Anesthetic. Wikipedia

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Mouth "Oil Pulling"

The other day, I had a patient ask me about "oil pulling." For those who don't know what oil pulling is:

"Oil pulling or oil swishing is a traditional Indian folk remedy that involves swishing oil in the mouth. It is mentioned in the Ayurvedic text Charaka Samhita, where it is called Kavala Gandoosha or Kavala Graha. Ayurvedic literature describes oil pulling as capable of both improving oral health and treating systemic diseases such as diabetes mellitus or asthma. While scientific evidence is lacking to support any systemic benefits of oil pulling, some studies have suggested that it may reduce oral plaque, halitosis, and gingivitis." [Wikipedia]

The oil used to swish the mouth is typically vegetable based like sesame or sunflower and is performed for 15-20 minutes before being spit out (or swallowed depending on what you want to accomplish).

Though there are plenty of testimonials on the internet and explanations for its amazing effects including the oil's alleged ability to suck plaque off teeth, absorb germs into the oil, make teeth whiter, etc I feel the oil's effects are more mundane in nature.

Just as chapstick is an oil-based compound that treats dried and chapped lips by coating the surface allowing the lip mucosa to heal, oil pulling may just provide a protective barrier to provide a similar function. Oils are essential to skin and mucosal health and when such oils are stripped, problems occur (ask anybody who washes their hand with soap multiple times a day).

As such, I personally don't think it can hurt if someone wants to give oil pulling a try to address oral problems. But I would not recommend this type of unproven treatment to address systemic disorders like diabetes or asthma over more established medical management.

Of note, the references listed below are studies published in less-than-authoratative journals.

References:
Tooth brushing, oil pulling and tissue regeneration: A review of holistic approaches to oral health. J Ayurveda Integr Med 2 (2): 64–8. doi:10.4103/0975-9476.82525.

Effect of oil pulling on Streptococcus mutans count in plaque and saliva using Dentocult SM Strip mutans test: a randomized, controlled, triple-blind study. J Indian Soc Pedod Prev Dent 26 (1): 12–7.

Mechanism of oil-pulling therapy - in vitro study. Indian J Dent Res 22 (1): 34–7. doi:10.4103/0970-9290.79971.

Effect of oil pulling on plaque induced gingivitis: a randomized, controlled, triple-blind study. Indian J Dent Res 20 (1): 47–51. PMID 19336860.

Effect of oil pulling on halitosis and microorganisms causing halitosis: a randomized controlled pilot trial. J Indian Soc Pedod Prev Dent 29 (2): 90–4. doi:10.4103/0970-4388.84678.

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Dental X-rays Linked to Brain Tumors

In a study spanning over decades, researchers have found an association between dental x-rays and increased risk of a non-malignant type of brain tumor called meningioma.

Of the four types of dental x-rays, only the full-mouth series was associated with this increased risk. More specifically, the risk was elevated with the aggregate number of full-mouth series in 10-year periods from approximately 15–40 years before diagnosis, with significant elevations in the 10-year periods beginning 22–30 years before diagnosis. The risks in these analyses were even greater when only women were considered.

One needs to be aware that radiation exposure from full-mouth series was much greater in the past than it is now and as such, this risk may be nominal (though not zero) with current dental x-ray technology.

However, it also should be a reminder that x-rays should not be routinely performed unless there is a very good reason to obtain especially in children who are more susceptible to radiation injury... and that applies to not only x-rays, but any kind of testing involving ionizing radiation including CT scans.

Some x-rays should NEVER be performed including sinus x-rays for sinus problems given a nearly 50% error rate in diagnosing the presence OR absence of sinus problems.

X-rays for nasal fractures is not recommended given x-rays rarely change how such fractures are managed.

Soft-tissue lateral x-rays to look for large adenoids should also be discouraged as nasal endoscopy can provide similar if not better information without any radiation exposure.

To know what the cancer risk is with different types of x-rays, check out this website!

Source:
Dental X-rays and the risk of intracranial meningioma. Cancer. Volume 100, Issue 5, pages 1026–1034, 1 March 2004

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