PRESCRIPTION AND DRUG INTERACTION IN THE ELDERLY

PRESCRIPTION AND DRUG INTERACTION IN THE ELDERLY

PLAN :

Introduction

1. Changes in drug pharmacokinetics and pharmacodynamics

1. Absorption modification
2. Changes in distribution and transport
3. Modification of hepatic metabolism
4. Change in renal elimination 
5. Other risk factors

2. General principles of therapeutic prescription in the elderly in odontostomatology:
3. Practical application of the Prescription in the elderly subject according to the risk of drug interaction:
   1. elderly subject free from any recurrent or intercurrent pathology
   2. elderly subject suffering from a chronic pathology
      1. Liver failure
      2. Renal failure
      3. Diabetes
      4. High blood pressure
      5. Heart failure

CONCLUSION 

PRESCRIPTION AND DRUG INTERACTION IN THE ELDERLY

Introduction

Prescribing a medication is not a trivial act, particularly in patients who present a physiological, pathophysiological or “therapeutic” risk: drug interactions. The physiological risk is represented by age, pregnancy and breastfeeding. Age poses therapeutic problems in subjects over 65 years of age. Indeed, the capacities of hepatic destruction and renal elimination in the latter are altered. As a result, the lifespan of medications is extended, which exposes the patient to a risk of drug toxicity. This is why the interview must specify whether the patient is under treatment for a given pathology in order to prevent a risk of interaction with the medications that a dentist may prescribe.

2. Changes in drug pharmacokinetics and pharmacodynamics

In general, liver and kidney function deteriorate with age, and this is even more the older the age. For example, glomerular filtration decreases by 25% at age 75 and by 50% at age 90, which significantly reduces the elimination of drugs filtered through the glomerular capillaries. The deterioration of kidney function associated with the reduction in hepatic degradation capacities requires, for certain drugs, a reduction in their usual dosage.

1. Absorption modification

• reduction of gastric acid secretion,
• decreased rate of gastric emptying, 
• reduction in the digestive resorption surface 
• decreased digestive perfusion.

In theory, these physiological changes could affect the rate of absorption and the amount of drugs absorbed.

2. Changes in distribution and transport

With age there is a decrease in total water and lean body mass, which increases the risk of overdose for water-soluble drugs. 

In addition, the increase in lipid mass increases the risk of prolonged storage and release of fat-soluble drugs, which often leads to an increase in the half-life. (Example: lengthening of the half-life of benzodiazepines which can go from forty hours in young subjects to four to five days in elderly subjects)

The modification of plasma transport is reflected by hypoalbuminemia which reduces the fixation of drugs strongly bound to albumin, thus increasing their free fraction and therefore potentially their toxicity (example: digoxin, hypoglycemic sulfonamides, anti-vitamin K, non-steroidal anti-inflammatory drugs, etc.)

3. Modification of hepatic metabolism

Hepatic drug transformation rate often decreased by reduced liver mass and hepatic blood flow

Naproxen® and Ibuprofen have reduced hepatic metabolism

4. Change in renal elimination: 

Classically, presence of chronic renal failure among other things because the glomerular blood flow is lowered. The decrease in glomerular filtration is 2 to 10% per decade. Therefore decrease in urinary excretion of certain drugs: (aminoside, digoxin, angiotensin converting enzyme inhibitors, low molecular weight heparin) 

5. Other risk factors

Multiple chronic diseases: polymedication

Multiple doctors: which can lead to polymedication. Treatments are often changed by a doctor without consulting other practitioners. This increases the risk of iatrogenic interaction. In dentistry, you should try to prescribe as little as possible.

2. General principles of therapeutic prescription in the elderly in odontostomatology:

The therapeutic act is not limited to the prescription of medications. It also includes a non-drug and psychological approach:

Before prescription:

● listen, examine  : prescribing a medication is not always the most appropriate response to the patient’s complaint.

● know the patient’s current pathologies and their history (hypertension, diabetes, heart disease, renal failure, etc.)  ; know all the medications taken by the patient

● assess weight, blood pressure, hydration status and nutritional status.

● ensure a diagnosis

● choose the medicine:

– having the fewest side effects and interactions,

– having the widest safety margin,

– having the shortest half-life,

– having the route of administration and the pharmaceutical form most suited to the patient’s disabilities (tremors, visual disturbances, cognitive disturbances, difficulties with manual gripping, etc.).

● avoid duplication by identifying all medicines that belong to the same therapeutic class, which contain the same active ingredient 

3. Practical application of the Prescription in the elderly subject according to the risk of drug interaction:
   1. elderly subject free from any recurrent or intercurrent pathology

• use suitable dosage forms
• adapt (by reducing) the dosage 
• clearly explain the prescription and the various risks to the patient.

2. elderly subject suffering from a chronic pathology

Liver failure

Imposes a reduction in the usual dosage of certain drugs metabolized by the liver (macrolides, paracetamol, amine-function anesthetics). 

Deficiency of coagulation factors, thrombocytopenia, and thrombopathia, can cause serious bleeding when salicylates and NSAIDs (antiplatelet action) are prescribed. They should be avoided.

Renal failure

In nephrotic syndrome there is a leakage of plasma albumin (hypoalbuminemia). As a result, the free fraction of all drugs that usually bind to plasma albumin increases. In such patients, the use of salicylates and all NSAIDs should either be reduced in dosage or replaced by corticosteroids.

Furthermore, in cases of renal insufficiency, blood pressure may be high and the intake of NSAIDs aggravates pre-existing high blood pressure.

Reduction of drug elimination requires adaptation of the dosage of penicillin (risk of convulsions in the event of an overdose).

Diabetes

• Insulin-dependent diabetics may experience glycemic imbalance when taking 

corticosteroids. If corticosteroids are prescribed, the number of insulin units will need to be increased

• NSAIDs and hypoglycemic sulfonamides: risk of a drop in blood sugar which may in 

severe cases, lead to hypoglycemic coma (pharmacokinetic interaction: competition at the albumin level)

High blood pressure

In the elderly, NSAIDs can initiate and, a fortiori, aggravate pre-existing high blood pressure by at least two mechanisms:

• Na+ retention which increases vascular contractility and therefore reduces the effectiveness of antihypertensive drugs;

• an antiprostaglandin action: (PG) plays an important role in blood pressure balance.

Heart failure

The administration of NSAIDs may be responsible for the development of congestive heart failure in the elderly. The authors showed that the probability of hospitalization for heart failure is multiplied by two in elderly patients treated with an NSAID. This risk is multiplied by ten in patients with a history of cardiac pathologies.

Patients treated with AVK should not receive NSAIDs; in fact, the latter prevent the binding of AVK to plasma proteins (competition), which increases their free fraction and increases the INR. This can result in hemorrhagic reactions.

Macrolides ( azithromycin , clarithromycin, erythromycin) present an associative risk with oral anticoagulants: increase in the anticoagulant effect: monitoring of the INR

The association: penicillin A-methotrexate is not recommended: increased hematological toxicity of methotrexate by inhibition of renal tubular secretion of penicillins

PRESCRIPTION AND DRUG INTERACTION IN THE ELDERLY

Conclusion 

Polymedication and drug interactions in the elderly remain a real public health issue, especially as life expectancy continues to increase. Better coordination between different health professionals seems essential and deserves to be developed. It should not be forgotten that in the elderly, medication should not be the only treatment and it is necessary to promote all non-drug therapeutic approaches. 

PRESCRIPTION AND DRUG INTERACTION IN THE ELDERLY

Wisdom teeth may need to be extracted if they are too small.
Sealing the grooves protects children’s molars from cavities.
Bad breath can be linked to dental or gum problems.
Bad breath can be linked to dental or gum problems.
Dental veneers improve the appearance of stained or damaged teeth.
Regular scaling prevents the build-up of plaque.
Sensitive teeth can be treated with specific toothpastes.
Early consultation helps detect dental problems in time.
 

PRESCRIPTION AND DRUG INTERACTION IN THE ELDERLY