Analgesia in Dentistry


Analgesia in Dentistry

St. Lawrence Dentistry performs dental procedures in the most gentle and conservative fashion possible and we make every effort to minimize the use of pain medications. However, sometimes they are indicated and they can be very effective.

The use of pain medications has changed markedly in the past decades in that codeine has been replaced by ibuprofen as the chief pain analgesic agent at our office. Ibuprofen was originally used for arthritis but research revealed that a dose of Ibuprofen 400 mg surpassed very strong narcotics and is the best for pain relief in dentistry. Further studies have found that a 600 mg Ibuprofen, which is available in a prescription form in Canada, is even more effective.

Ibuprofen is classified as a Non Steroidal Anti Inflammatory drug or ‘NSAID’. The way is works is quite interesting. When there is tissue damage arachidonic acid in your body produces two enzymes called COX1 and COX2. NSAIDS work by blocking these.

In the absence of NSAID medication, COX1 usually produces natural compounds called ‘prostagladins’ and ‘thromboxane’. Prostaglandins are very important for the kidney and uterine contraction, and stomach protection. However, these functions are not affected much if a Ibuprofen prescription is just used 4-5 days (the typical duration of a dental analgesic prescription).

COX1’s production of thromboxane is important as this is what allows for platelet aggregation. Platelets are a component of blood which helps with blood clotting. This is why when you taking NSAIDS type medications you can get excess bleeding. COX2 has the same effects as COX1 except in does not touch thromboxane.×1000/filters:no_upscale():max_bytes(150000):strip_icc()/best-anti-inflammatory-medication-2548734-v1-492cf2387f3949718cf557e9592f4ccb.png

When prescribing NSAID medications, Dr. Hawryluk will carefully consider the side effects they have and weigh them against the benefits they may have for you. The reactions with NSAID drugs are increased bleeding, dyspepsia (indigestion), stomach lining damage, kidney impairment, and allergies. It is common for these medications to cause pinpoint bleeding in stomach. NSAIDS should not be used on patients with gastric ulcers, bleeding concerns, hypersensitivity, kidney disease, or late in pregnancy,

NSIADS may interact with cardiovascular medications, central nervous system medications like lithium, acetaminophen (Tylenol), anti coagulants, and others.

One group of people who really have to watch taking ibuprofen type pain relievers are those on ACE inhibitors (medication for high blood pressure). These rely on good kidney blood flow, and NSAIDS interfere with this. However, in general, if you are just on Ibuprofen for less than a week there should be minimal effects.

It is important you list all the medications you are taking on our medical history form so we can make safe analgesic choices for you. The drug Methotrexate interacts with NSAIDS but if only a low does of methotrexate is being used (such as for arthritis treatment) it is usually inconsequential. However, if it is a higher dose such as for cancer treatment, combining these two drugs together can be fatal. Sometimes the drug misoprostol is used with NSAIDS as it is prostaglandin and can limit stomach ulcers when taking NSAIDS. However this drugs can have drastic effects on pregnancy and is actually used for abortions. This underscores how essential accurate intake of your medical information is when we are prescribing medications.

In the past we have often written pain prescriptions as ‘prn’ or as needed. However, research has shown that if we are anticipating moderate pain after a procedure consideration for a pre-procedure dose or round the clock dose instead of ‘as needed’ can be effective in managing pain you may be having. Effective pain relief by medications usually entails first maximizing non opioid medications before adding opioids.

One common prescription given at our office is the following:

  • Ibuprofen 400-600mg, every 6 hours

For most people the daily maximum of this medication 2400 mg. Advil and Motrin are examples brand names of this medication. In Canada 600 mg tablets come in a prescription form.

Other effective common prescriptions of NSAIDS are:

  • Flurbiprofen 50-100mg every 6 hours, daily max of 300 mg
  • Diflunisal 1000 mg STAT (loading dose) then 500 mg every 12 hours, Daily max 1.5 grams
  • Naproxen 500/550mg STAT, then 250/275mg every 6-8 hours, daily max 1375 mg

Ibuprofen use is usually great for dentistry because we do not use it long enough on patients to cause many side effects. The big issue with Ibuprofen is its long term use in medicine. As stated previously it blocks enzymes in your body which can cause bleeding. It has been estimated that about 16 thousand people die each year in the USA from long term bleeding issues caused by NSAIDS. A newer class of NSAIDS has been developed to combat this bleeding issue. These are NSAIDS but they only block the COX2 enzyme so they cause less bleeding. Celebrex is the only one available in the Canadian market. It is not recommended for any patient who has heart issues.

A typical prescription for this medication is:

  • Celebrex 200 mg bid (twice daily )for dental pain.

Acetaminophen (Tylenol) is another good choice in many situations for dental pain control. It offers analgesic, antipyretic (fever reduction), and causes no bleeding issues.

A typical adult dose for mild/moderate pain is:

  • Tylenol 325 mg tablets, 1 every 4 hours

A typical pediatric dose given for dental pain is:

  • 10-15mg/kg every 4 hours to a maximum of 65mg/kg/day

Currently in Canada the adult maximum dose is 4 grams/day. However, as of 2019 the government is thinking of lowering this recommendation as there are so many products containing Tylenol and they are worried about people doubling them up.

The main drawback of Tylenol is that high does can damage the liver as the metabolism of Tylenol occurs in the liver. The main metabolism process is called ‘glucorination’ and ‘sulfation’. In addition, 4% of acetaminophen is metabolized by ‘CYP2E1’ to a very toxic metabolite called ‘NAPQI’ – this is usually not an issue because this is further broken down by ‘glutathione’. Problems occur if a patient has liver disease as these patients have less glutathione and hence toxic metabolites can build up.

Opioids in dentistry are generally reserved for more severe pain and work by binding into opioid receptors called ‘mu, kappa, and delta’. In addition to pain relief, they have other effects which are not limited to: sedation, cough relief, respiratory depression, constipation, low blood pressure, urinary retention, and nausea.

Some common opioid dosage used are:

  • Codeine 60 mg, 1 tablet every 4-6 hours
  • Oxycodone 5-10mg, 1 tablet every 4-6 hours
  • Hydromorphone 2-4mg, 1 tablet every 4-6 hours (rarely used in dentistry)

Codeine by itself is a ‘weak agonist’ which means it is metabolized to morphine in the liver by ‘2D6 portion of cytochrome p450’. Sometimes patients report codeine does not offer them much pain relief. This can be because there is a genetic variability of how much ‘2D6’ you actually have. St. Lawrence Dentistry does not recommend codeine for breast feeding mothers because of the 2D6 variability. If codeine is not metabolized it can pass on to the breast milk creating terrible consequences.

In Canada Tylenol is available as a combination product with codeine. In particular the doses of codeine in these products are 8,15,30,60 mg respectively. All these products have 300 mg of acetaminophen.

In addition, Tylenol is available with the opioid Oxycodone as a combination product. This stronger medication is only reserved for specific intense pain issues in dentistry. It is available in 2.5 and 5 mg doses with Tylenol.

An example of a pain script for oxycodone on its own is:

  • Oxycodone 5-10mg, one tablet every 4-6 hours in the presence of pain

In general Dr. Hawryluk will try and limit the use of these opioid products as they can be addictive. In the case where someone cannot take NSAID medications but has severe pain acetaminophen is considered in up to 1000 mg doses before the addition of opioid medications.

St. Lawrence Dentistry wants to make your dental experience pleasant and will try and minimize any discomfort. When analgesics are indicated we will make conservative and responsible choices for your comfort and well being.

If you live in the Mississauga area and would like to talk about this topic further please give us a call.

Reference: University of Toronto, Faculty of Dentistry online Lecture series 2018.