Oral Health Group

Pharmacology Made Easier

March 1, 2013
by Janice Goodman, DDS

Dentists prescribe a handful of familiar drugs. Maybe we shouldn’t be quite so comfortable with writing those prescriptions. Some of our patients are walking poly pharmacies and dentists are responsible to be familiar with drug interactions and adverse side effects — a daunting task.

Enter, the new age of pharmacology software on your personal digital assistant. Fabulous sites are available for free or a nominal fee to download. These websites make it quick and easy to input a patient’s medications and find out anything that you need to know in less than a minute. This exercise could be done on every patient in your office who is taking multiple medications (>2) and the task can easily be accomplished by auxillaries or front desk personnel.


Two popular sites I have tried and like, are Lexi-Comp (www.lexi.com) and Epocrates Rx Online (www.epocrates.com). Lots of other sites are available such as Clinical Pharmacology online; Google (good for odd drugs); PDR (not good for drug interactions), www.gsm.com (good program for providing patient handouts). Most sites provide different levels of information with the most basic being cheaper or free.

Why you should use these sites:

• To look up drugs that you don’t know;

• To find metabolic pathways when you are adding a second drug e.g. CYP 450 enzyme system metabolism;

• Cross-check for drug-drug in­ter­actions;

• Check for adverse drug reactions and side effects;

• Check if you can use for pregnancy, breast feeding, very old, or very young;

• Check doses and many other uses (e.g. herbal meds, alternative meds — cross reactions);

• Print handouts to give to patients about the medicine that you are prescribing — great PR;

• Look for alternative drugs for infectious diseases and get suggestions for prescribing.

Another suggestion for an inexpensive prescription information source is: Peter Jacobsen —Little Dental Drug Book 2005/6 Paperback $6.95 has a set of written prescriptions and is often given out to graduating dental students.

Internet resources help you understand metabolic pathways and drug metabolism. Ninety percent of all drugs are metabolised in the liver, involving P450 enzymes, and they are largely eliminated through the kidneys. When adding a new drug, one must always consider that the substrate may be affected by inducers or inhibitors, increasing or decreasing plasma levels. It is necessary to know if it is a prodrug requiring CYP450 enzymes to activate it or if it will affect other drugs that the patient is already on that utilizes a common enzyme. For example, an antibiotic such as erythromycin, prozac, biacin and grapefruit juice are inhibitors of CYP3A4 (increases blood levels), so any other drug that uses CYP3A4 to break them down or activate them may become toxic to an individual if the doses are not altered. (e.g. methyl prednisone or acetaminophen). This software makes it easy to pick up these problems and will help protect you should a problem occur.

Adverse drug reactions are the 4th leading cause of death and are seen greater in patients with diabetes, pulmonary issues, AIDS, chronic alcoholics, and MVAs . It is estimated that there are over two million adverse drug reactions a year in the US with over 100,000 deaths. Co-administration of drugs, homeopathy, OTC products, Vitamins, CAM (Complementary Alternative Medicine) products, some foods or juices have the potential to enhance or inhibit each other’s effects on that individual. Fifty-seven percent of all CAM users do not tell their doctors about them and 52% of the Australian population is reported to use CAM products. It is important to ask if the patient is taking supplements or illegal/leisure drugs that would not normally be reported. This information must be updated at every opportunity and recorded in the chart.

The aging population are at high risk because they tend to be on so many medications and often do not follow instructions or report accurately. In nursing homes there are over 350,000 reported adverse drug reactions/year. The majority of the elderly take at least one antihypertensive drug. Often the elderly will take an OTC antihistamine to contribute to dry mouth, taste changes, stomatitis, dental disease or affect other medications they are on.

Treating drug created problems is estimated to cost $136 billion annually. Even if the elderly are not taking medications, they are at a higher risk for side effects because of their thinner GI tissues, lower hepatic volume, weight and blood flow, secondary disease such as renal disease, cardiac, endocrine, etc. Patients are commonly on blood thinners, C-V drugs, antidepressants/sedatives and they truly need extra time to get the best and most inclusive information.

1. Above all a good medical history is paramount to avoid any issues. Ask about current drugs, recent, but not used drugs, compliance, OTC drugs, vitamins and herbal use, allergic profile, past side effects, adverse drug reactions/ drug-drug reactions, drug/alcohol dependency, family history and genetic issues with certain medications. Studies show noncompliance rates are as high as 59%.

2. Look for high-risk patients: the frail or elderly, polypharmacy patients (>than two medications), antibiotics, digoxin, anticonvulsants, warfarin, etc.

3. Consult a PDA online program.

4. Have a handout for every medication and review it with each patient and every time you prescribe it. OH

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