PHARMACOKINETICS 2

Question 1

IN EACH BODY COMPARTMENT A DRUG MAY BE IN ITS ………… OR …………. FORM. THE USEFUL FORM IS THE …………… FORM.

Answer 1

FREE
BOUND
FREE

Question 2

WHAT ARE THE FEATURES OF THE BLOOD BRAIN BARRIER

Answer 2

ENDOTHELIAL CELL
LINE VESSELS OF CNS
FORM TIGHT JUNCTIONS IMPERMEABLE TO WATER SOLUBLE MOLECULES

Question 3

WHAT CROSSES THE BBB EASILY

Answer 3

LIPID SOLUBLE MOLECULES

Question 4

WHAT HAPPENS TO THE BBB DURING INFLAMMATION

Answer 4

THE TIGHT JUNCTIONS BECOME LEAKY

Question 5

WHAT IS THE ADVANTAGE OF LEAKY TIGHT JUNCTION DURING INFLAMMATION

Answer 5

WATER SOLUBLE DRUGS CAN CROSS MORE EASILY TO TREAT THE INFLAMMATION

Question 6

WHAT IS AN EXAMPLE OF A WATER SOLUBLE DRUG TO TREAT CNS INFLAMMATION

Answer 6

PENICILLIN TO TREAT MENINGITIS

Question 7

WHAT IS THE CHEMORECEPTOR TRIGGER ZONE

Answer 7

AN AREA OF THE MEDULLA OBLONGATA OUTSIDE OF THE BBB THAT CAN RECEIVE INPUT FROM DRUGS AND IS INVOLVED IN THE VOMITTING REFLEX

Question 8

WHY ARE DOM PERIDONE AND APOMORPHONE COADMINISTERED

Answer 8

APOMORPHINE IS A DOPAMINGERGIC AGONIST USED IN THE TREATMENT OF PARKINSONS
DOM PERIDONE IS A DOPAMINERGIC ANTAGONIST USED TO TREAT NAUSEA AS A RESULT OF PARKINSONS
THEY DO NOT COUNTERACT EACH OTHER BECAUSE APOMORPHINE CROSSES THE BBB AND DOMPERIDONE DOES NOT

Question 9

IF A DRUG BINDS TO A PROTEIN IT IS ………… FREE TO ASSOCIATE WITH A …………….. BINDING ALSO IMPACTS UPON …………………………. AND ……………………………..
HIGH PROTEIN BINDING CAN LEAD TO LARGE UNEXPECTED ………………… IN CONC OF DRUG AS BINDING SITES BECOME ………………………..

Answer 9

NOT
RECEPTOR
METABOLISM
ELIMINATION
INCREASES
SATURATED

Question 10

HIGHLY LIPOPHILIC DRUGS WILL PARTITION INTO SPECIFIC TISSUES LIKE FAT CAUSING THE DRUG TO ………………….. MAKING IT DIFFICULT TO ACHIEVE THE CORRECT DRUG ……………… AND MAY CAUSE THE DRUG TO BE IN THE SYSTEM ………………….. THAN ANTICIPATED.

Answer 10

RESERVOIR
CONCENTRATION
LONGER

Question 11

WHAT ARE THE PHASES OF DRUG METABOLISM

Answer 11

PHASE 1 - CATABOLISM - CAN PRODUCE A MORE REACTIVE FORM OR PRO DRUG TO A DRUG
PHASE 2 - ANABOLISM - RENDER TO INACTIVE PRODUCT

Question 12

WHAT ENZYMES METABOLISE DRUGS IN

Answer 12

MICROSOMAL ENZYMES SUCH AS CYTOCHROME P450

Question 13

WHAT INFLUENCES METABOLISM

Answer 13

SITE OF ADMINISTRATION

Question 14

WHY CAN YOU ALTERNATE IBUPROFEN WITH PARACETAMOL

Answer 14

THEY ARE METABOLISED BY DIFFERENT ISOFORMS OF P450

Question 15

LEVEL OF TRANSCRIPTION OF CYTOCRHROME P450 CAN BE AFFECTED BY WHAT

Answer 15

ENVIRONMENTAL FACTORS SUCH AS FOODS

Question 16

WHY IS PARACETAMOL OVERDOSE DANGEROUS

Answer 16

ITS INTERMEDIATE IS TOXIC
IF THERE IS TOO MUCH (SATURATION) FOR MICROSOMAL ENZYMES TO METABOLISE THEN THE INTERMEDIATE WILL NOT BE INACTIVATED IN TIME AND CAUSE DAMAGE

Question 17

WHAT ARE THE METABOLIC STAGES OF ASPRIN

Answer 17

ASPIRIN —– SALICYLIC ACID —— GLUCURONIC CONJUGATE

Question 18

HOW ARE DRUGS ELIMINATED

Answer 18

THROUGH URINE, FAECES, MILK, SWEAT , EXPIRED AIR

Question 19

WHAT TYPES OF RENAL EXCRETION OCCUR

Answer 19

GLOMERULAR FILTRATION
ACTIVE TUBULAR SECRETION
PASSIVE DIFFUSION

Question 20

WHAT ROLE DOES GLOMERULAR FILTRATION IN RENAL EXCRETION OF DRUGS

Answer 20

SMALL MOLECULES <20KD

Question 21

WHAT ROLE DOES ACTIVE TUBULAR SECRETION IN RENAL EXCRETION OF DRUGS

Answer 21

ACTIVE TRANSPORT ACROSS THE MEMBRANE
ORGANIC ANION TRANSPORTER (WEAK ACIDS)
ORGANIC CATION TRANSPORTER (WEAK BASES)

Question 22

WHAT ROLE DOES PASSIVE DIFFUSION IN RENAL EXCRETION OF DRUGS

Answer 22

LIPOPHILIC

Question 23

WHAT MAY BE AFFECTING DRUG CLEARANCE IN ELDERLY PATIENTS

Answer 23

DECREASED RENAL, GASTROINTESTINAL AND LUNG FUNCTION

Question 24

IF A PATIENT REQUIRES 200MICROMOLES OF A DRUG PER DAY EXPLAIN THE CONSIDERATIONS OF HOW TO DOSE THE PATIENT

Answer 24

INFUSION OVER A DAY IS A BETTER ROUTE BUT IMPRACTICAL FOR A PATIENT
MULTIPLE DOSES MAKES SURE THE PATIENT DOES NOT OVER DOSE BUT IMPRACTICAL FOR THE PATIENT (RETURNING FOR DOSE, BRUISING ETC)
ON INJECION OF A LARGE AMOUNT OF DRUG CAN BE DANGEROUS IF THE DRUG DOES NOT HAVE A HIGH SAFETY MARGIN
ALL HOWEVER HAVE THE SAME EQUILIBRIUM OUT COME

Question 25

WHAT IS DRUG EQUILIBRIUM

Answer 25

RATE OF INTAKE = RATE OF EXTRUSION

Question 26

WHAT CAN HAPPEN IF RATE OF INTAKE > RATE OF EXTRUSION

Answer 26

CONCENTRATION WILL RISE UNTIL ENZYMES ARE OVERWHELMED AND LEVELS ARE NO LONGER CONTROLLED
THIS IS SATURATION KINETICS