Drug therapy in elderly

1. DRUG THERAPY IN
ELDERLY

2. classification
 >65 years
 65- 75 – young old
 Up to 85 – old old
 > 85 - very old

3. Reasons for considering drug therapy in
elderly as a specific group
 Physiological and pharmacological changes in elderly
 Elderly consume good portion of health expenditure
 ADRs more common in elderly
 Polypharmacy more (multiple diseases): drug interactions
more
 Increased error in taking medicines
 Frailty, poor appetite and nutrition, forgetfulness,visual
impairment, lack of self care, lack of supervision, financial
problems

4. Physiological changes
 Changes in body composition : lean body mass,
body size, body water,bone density, albumin AND Increased
body fat & α1 acid glycoprotein
 GIT : gastric acidity,Delayed gastric emptying time, in GIT
& liver blood flow.
 RS : in total vital capacity & bronchial ciliary function
 CVS : in baroreceptor activity,COP & myocardial sensitivity to
beta agonists/antagonists
 Renal : GFR,renal blood flow& tubular secretion
 NS : Cognition defects,Reduction in central NTs, Impaired
cerebral autoregulation

5. Physiological changes contd….
 GU : Prostate hypertrophy in males,Vaginal
atrophy and menopause in females
 Endocrine : Increased incidence of DM & thyroid
disorders
 Musculoskeletal : Reduction in muscle mass ,Power &
Joint flexibility.

6. Pharmacological changes
 Pharmaceutical factors
 Pharmacokinetic changes
 Pharmacodynamic changes

7. Pharmaceutical factors
 Difficult to swallow Tab , Capsules
 Easy to swallow syrups, suspensions
 Medicines should be in easily opened containers
 Labelling in large print , clear

8. Pharmacokinetic factors
 Absorption : Drugs absorption from intestine is slow
( decreased motility & decreased blood flow)
 Distribution : Increase in free acidic drugs (decreased plasma
albumin & decrease in free basic drugs (increased α1 acid
glycoprotein). Lipid soluble drugs accumulate more (body fat more in
elderly)
 Metabolism : Enzyme activity in liver decreasedoral
bioavailability of drugs with high first pass metabolism increased.
 Excretion : Excretion of drugs decreased (renal function reduction).
Dose of drugs excreted through kidney has to be reduced.

9. Excretion
 Cockcroft-Gault formula
Creatinine clearance ml/mt
= (140-age)× wt(Kg)
72 X S.Creatinine
Females – multiplied by 0.85

10. Pharmacodynamic factors
 Reduction in receptors
 Reduced sensitivity of receptors

11. ADRs peculiar to elderly
 Treatment of HTN often results in postural hypotension, falls,
injury (cerebral autoregulation deficient, peripheral autonomic
responses sluggish in response to hypotension)
 Diuretics lead to hypokalemia & can lead to digitalis toxicity if co-
administered.
 Brisk diuresis can lead to A/c urinary retension in old men with
BPH
 Precipitation of gout with diuretics
 Confusion precipitated with anticholinergis/antihistaminics
 Use of antipsychotics can lead to parkinsonism for which elderly
are more prone
 Greater incidence of peptic ulcer with NSAIDs(due to decreased
clearance of NSAIDs)

12.  Constipation precipitated by anticholinergics / opioids /
antipsychotics

13. CNS drugs
Sedative hypnotics
 Prolongation of half life of benzodiazepines, barbiturates
(due to decreased metabolism-excretion)
Half life of Lorazepam,Oxazepam less
affected. Hence preferred over Diazepam,
barbiturates
 Side effects like ataxia, motor incoordination to be looked for
while prescribing these drugs.

14. CNS drugs
Opioid analgesics
 Elderly sensitive to respiratory depression due to decreased
respiratory reserve.
 Morphine, codeine use justified in chronic painful conditions but
with caution

15. CNS drugs
Antipsychotics
Classical antipsychotics associated with EPS & can worsen
Parkinsonism if present.Their Anticholinergic effects can worsen
BPH, AD if present. Alpha blocking property (CPZ) can cause
orthostatic hypotension
Atypical antipsychotics (eg :Olanzapine,Aripiprazole) preferred.
Antidepressants
 Avoid TCA with anticholinergic S/E ( Preferred – Nortriptline,
Desipramine)
Safe - SSRI

16. CNS drugs
Antimania
Li excreted by kidney. Doses in elderly should be adjusted
depending on kidney function.Thiazides reduce Li clearance. Li
doses should be reduced further in presence of thiazides.
Carbamazepine, Valproic acid preferred over Li

17. CVS
Antihypertensives
Thiazides are 1st
step in Rx of HTN. Low doses are used because
of higher incidence of arrhythmias, DM, gout in elderly.
(hypokalemia, hyperglycemia, hyperuricemia are S/E of thiazides)
CCBs are safe & useful if angina is coexistent
B blockers less useful unless heart failure present. Can be
dangerous in COPD patients. Can cause bradycardia in elderly.
ACEI less useful unless DM/heart failure present
Check for orthostatic hypotension in all elderly receiving
antihypertensives

18. CVS
Cardiac glycosides
 Digoxin - half life increased as Clearance decreased
(decreased renal function). Hence digoxin dose to be
adjusted according to kidney function.
 Elderly more sensitive to digoxin induced arrhythmias &
Extra cardiac side effects

19. cvs
Antiarrhytmics
 Avoid Disopyramide due to its anticholinergic effects &
negative inotropic effects.
Reduce dose of Qunidine, Lignocaine (as their excretion
through kidney reduced)

20. Antiinflammatory drugs
NSAID – GI bleeding, renal damage
Steroids – Osteoporosis

21. Antidiabetics
Chlorpropamide, Glibenclamide not used –hypoglcemia high
Glipizide, Gliclazide – used
Metformin
Nateglinide

22. Antibiotics
Penicillin, Cephalosporin,Nitrofurantoin, FQs,
Aminoglycosides --- dose adjusted
Tobramycin
Ceftriaxone, Cefperazone

23. Principles of treatment in elderly
 Careful drug history
 Prescribe only for specific & rational indication
 Define the goal of therapy
 Start with lowest dose & titrate
 Avoid Polypharmacy
 If possible-One drug for two indications
 Avoid symptomatic treatment without specific diagnosis
 Choose the right dosage forms
 Financial problems – prescribe cheaper alternatives
 rule out non compliance/errors in taking drugs
 Watch for ADRs & drug interactions

24. Drug therapy in
Pregnancy & lactation

25. Introduction
 Most drugs administered to mother can cause placenta and
affect the fetus
 Teratogenic affects are the important consideration while
prescribing during pregnancy
 History : Thalidomide disaster

26. USFDA drug categories in
pregnancy
A Adequate studies in pregnant women,
show no risk to fetus
Inj MgSo4, thyroxine,
folic acid
B Adequate human studies lacking but animal
studies show no risk to fetus OR adequate studies
in pregnant women show no risk to fetus but
animal studies have shown an adverse effect on
fetus
Penicillin, Amox,
erythromycin, paracetamol,
lignocaine, cefaclor
C No adequate studies in pregnant women, animal
studies are lacking/show adverse effect on fetus,
but potential benefit may warrant use of the drug in
pregnant woman despite the potential risk (RISK
CAN’T BE RULED OUT)
Most drugs (morphine,
steroids, adrenaline,
bupivacaine, atropine)
D Evidence of fetal risk, but potential benefit may be
acceptable despite potential risk (POSITIVE
EVIDENCE OF RISK)
Aspirin, antiepileptics
X Studies in humans/animals show fetal risks.
Absolutely contraindicated
Isotretinoin, estrogens,
cytotoxic drugs

27. Examples of teratogenic effects
Thalidomide Phocomelia
Methotrexate Hydrocephalus, cleft palate
stilboestrol Vaginal adenocarcinoma in teenage offspring
Tetracycline Bone & teeth abnormalities
Warfarin CNS & skeletal defects
Phenytoin Hydantoin syndrome
Carbamazepine NTD
Valproate Spina bifida
ACEI Renal tubular dysgenesis, oligohydramnios
Lithium Fetal goitre, Ebstein’s anomaly
Isotretinoin Craniofacial, CVS defects

28. Principles of prescribing in
pregnancy
 Wherever possible, use non drug therapy
 Prescribe drugs only when definitively needed
 As far as possible, avoid medication in the first trimester of
pregnancy
 Use lowest effective dose for shortest period & if possible
give drug intermittently
 Choose drugs having best safety record over time
 Avoid newer drugs unless safety is clearly established
 Discourage patient from self medication & OTC.

29. Prescribing for common problems during
pregnancy
Nausea, vomiting Reassurance, high carbohydrate
diet, antihistaminic-antiemetic
(diphenhydramine, doxylamine)
Heartburn Avoid fatty food/alcohol/smoking. Non
systemic antacids & Metoclopramide
constipation High fibre diet, plenty of oral fluids, mild
laxatives like milk of magnesia, bisacodyl

30. Safe & unsafe drugs for various disorders
in pregnancy
SAFE NOT SAFE
ANTIMICROBIAL THERAPY
B lactam antibiotics, erythromycin base,
nitrofurantoin, methenamine, nystatin,
miconazole
erythromycin estolate (hepatotoxicity),
Aminoglycoside, TC, Chloramphenicol,
Co-trimoxazole, Sulfonamides, nalidixic
acid, Griseofulvin, Ketoconazole, FQs
ANTITUBERCULAR DRUGS
INH, Ethambutol Rifampicin, Streptomycin
ANTHELMINTHICS
Metronidazole (low doses), Diloxanide,
Chloroquine, Quinine, Piperazine, Pyrantel
Primaquine, mefloquine, Mebendazole
ANALGESICS
Paracetamol Aspirin , other NSAIDs

31. ANTIHYPERTENSIVES
Alpha methyl dopa, CCB, labetalol B blockers, ACEI, ARBs
HEART DISEASE
Similar treatment as non pregnant with
Digoxin
ANTICOAGULANT
Heparin warfarin
ASTHMA
Inhaled B agonists, inhaled steroids
DIABETES MELLITUS
Diet restriction, insulin if needed OHA
THYROTOXICOSIS
Propylthiouracil> carbimazole Radioactive iodine
EPILEPSY
PB , (Phenytoin) (supplement folic acd &vit K) Valproic acid, Carbamazepine

32. Other CNS drugs
BZD, Barbiturates, antidepressants,opioids (best avoided
near term to avoid neonatal CNS depression)
Lithium

33. Prescribing during lactation
 Most drugs administered to lactating mother detected in
breast milk(in lower conc than maternal plasma)
 Ideally medicines to be taken 30-60 min after nursing or 3-4
hrs before next feed to allow time for many drugs to clear
from mother’s blood.
 Drugs for which safety during lactation not established
should be avoided/breast feeding avoided during their
use.Eg : Anticancer drugs, immunomodulators

34.  Drugs excreted in high conc in breast milk & those which can
cause adverse effects in infant : Tetracyclines, INH, Sedative-
hypnotics, Opioids, Lithium, radioactive iodine
 Drugs which are excreted in small amounts in breast milk but
can cause adverse effects in fetus: Penicillin (hypersensitivity),
sulfonamides(hypersensitivity, kernicterus, hemolysis in G6PD
deficient infants)

35.  Drugs that are safe : insulin, adrenaline(destroyed in gut of
infant)
warfarin, caffeine, digoxin, propranolol,
thiazides, spirinolactone, tolbutamide,
ACEI, Antihistaminics, Carbamazepine,
Rifampicin, Pyrazinamide, Ethambutol,
Nifedipine, Clavulanic acid (very low
conc in milk…hence safe)