PHARMACOTHERAPY

PharmacotherapyPharmacotherapy

Principally concerned with the safesafe and effectiveeffective management of drug administration.

Implies an understanding of pharmacokinetics (PK) and pharmacodynamics (PD) so that individual dosing guidance, can be provided to optimize patient response .

Pharmacokinetics What the body does to the drug– Absorption– Distribution– Metabolism– Elimination

Pharmacodynamics What the drug does to the body– Response– Toxicity

PharmacotherapyPharmacotherapy

METABOLISM

ABSORPTION

ELIMINATION

- Site (i.e., GIT, skin, tissue depot)

- First-pass effect (oral)

- Drug properties (i.e., solubility) -Pathway(s)

-Sites (GIT, liver, lung)

DISTRIBUTION

SITE(S) FOR THERAPEUTIC EFFECT(S)

SITE(S) FOR TOXIC EFFECT(S)

PharmacologicActivity

ToxicActivity

Free Drug in Plasma or Extracellular Fluid

Distribution in Blood Cells

Bound to plasma proteins

- Unchanged drug

- Metabolites

- Sites (Tissues, fat, etc)

- Binding

Excretory Sites

Urine, Feces, Expired AirActive/inactive metabolites

Rational Drug Use

Supported by USAID

Prescribing, Dispensing,

Counseling and Adherence

Definition The rational use of drugs requires that:

– patients receive medications appropriate to their clinical needs,

– in doses that meet their own individual requirements

– for an adequate period of time, and – at the lowest cost to them and their

community.

WHO conference of experts, Nairobi 1985

DRUG

DOSE

TIME

ROUTE OF ADMINISTRATION

PRICE

Importance of RDU

An irrational drug use results in the following:

– Treatment failure

– Rapid development of drug resistance

– Increase of toxicity risk

– Wastage of money

Rational Drug Use

Prescriber, Dispenser &

their workplaces

Drug Supply System

Patient & community

Many Factors Influence Use of Medicines

Policy, Legal and Regulatory framework

Drug Use Process

Diagnosis: Aspects that lead to Irrational Drug Use

Inadequate examination of patient

Incomplete communication between patient and doctor

Lack of documented medical history

Inadequate laboratory resources

Prescription: Types of Irrational Drug Use (1)

Irrational Drug Use

Occurs If a Drug Is Prescribed When:

Underprescribing Needed medications are not prescribed Dosage is inadequate Length of treatment is too brief

Prescription: Types of Irrational Drug Use (2)

Irrational Drug Use

Occurs If a Drug Is Prescribed When:

Incorrect prescribing

Drug given for incorrect diagnosis Wrong drug selected for diagnosis Prescription prepared improperly Adjustments not made for co-existing

medical, genetic, environmental, or other factors

Prescription: Types of Irrational Drug Use (3)

Irrational Drug Use

Occurs If a Drug Is Prescribed When:

Extravagant prescribing

A less expensive drug provides comparable efficacy and safety

Symptomatic treatment of mild

conditions diverts funds from treating serious illness

Brand-name drug used when less

expensive equivalents are available

Prescription: Types of Irrational Drug Use (4)

Irrational Drug Use

Occurs If a Drug Is Prescribed When:

Overprescribing Drug is not needed Dose is too large Treatment period is too long Quantity dispensed is too great for

current course of treatment

Prescription: Types of Irrational Drug Use (5)

Irrational Drug Use

Occurs If a Drug Is Prescribed When:

Multiple prescribing

Two or more medications are used when fewer would achieve same effect

Several related conditions are treated

when treatment of primary condition would improve or cure the other conditions

Dispensing: Types of Irrational Drug Use

Incorrect interpretation of the prescription

Retrieval of wrong ingredients

Inaccurate counting, compounding, or pouring

Inadequate labeling

Unsanitary procedures

Packaging:– Poor-quality packaging materials– Odd package size, which may require repackaging– Unappealing package

Adherence vs Compliance

Adherence: The act or quality of sticking to something; steady devotion; the act of adhering

The acceptance of an active role in ones health care

Compliance: the act of yielding, conforming,

Consequences of Poor Adherence

For the individual:

– Treatment failure: incomplete viral suppression, continued destruction of the immune system, disease progression

– Drug resistance: emergency of resistant viral strains – Limited future treatment options: more complex

treatment, more toxicity, uncertain prognosis

SLEPTIN

AWAYFROM HOME

RAN OUT OF

PILLS

FELT ILL

FELT BETTERPILLS

DO NOT HELP

FEAR SIDE

EFFECTSDID NOT WANT

OTHERS TO SEE

FAMILY SAID NO TO MEDICATIO

N

FORGOT/ BUSY

DID NOT UNDERSTAND INSTRUCTION

S

MISSED DOSES

TAKING PILL

HOLIDAYS

UNABLE to CARE

FOR SELF

Adherence: Why do Patients Miss Doses? (Barriers to adherence)

Let’s find together a solution for your problem

•I am listening•You can trust me•I understand •I suggest…•What do you think?•I’ll explain to you how to take these medicines

Other Barriers to adherence

Communication difficulties

Literacy levels

Inadequate knowledge of disease

Inadequate understanding of effectiveness of medications

Lack of social support

Discomfort with disclosure status

Difficult life conditions

Alcohol and drug use

Depression and other psychiatric problems

Adherence Multi-disciplinary Roles

Same message from all!

Adherence Message for the patient

Doctors Adherence Nurse

PharmacistFamily/ Friends

Counselor Social

Worker

Methods and Challenges of Measuring Adherence

Self reports

Pill counts

Pharmacy records

Provider estimate

Pill identification test

Biological markers

Electronic devices

Measuring drug levels

A multi-disciplinary team work is required to achieve Rational Drug

Use !!!

Doctor

PharmacistCounselor / Treatment supporter

NurseCommunity

CLASSES of DRUGSDrugs affecting the Autonomic Nervous System

Drugs affecting the CNS– Antiparkinson drug– Anti-anxiety– Hypnotic drugs– CNS Stimulants– Anesthetics– Antidepressant drugs– Anti-epilepsy

Drugs affecting Cardiovascular system– Drugs for congestive heart failure– Anti-arrythmic drugs– Antianginal drugs– Antihypertensive drugs– Drugs affecting blood– Antihyperlipidemic drugs

Drugs affecting respiratory system

Diuretic drugs

Gastro-intestinal drugs

Antiemetics

Oral Hypoglycemic drugs and Insulin

Hormones of the Pituitary and thyroid

Steroid hormones

Anti-inflammatory drugs

Chemotherapeutic drugs

– Antibacterial

– Antifungal

– Antiprotozoal

– Anthelmintic

– Antiviral

– Anticancer