Janina Myka P. Maligaya Sept.
10,2020
BSN - 2B
NCM06 - PHARMACOLOGY
Answer the following by encircling the letter of the correct answer. Strictly no
erasure.
When two drugs with similar actions are taken for a double effect is called?
a. Synergistic effect
b. Antagonistic effect
c. Additive effect
d. Displacement
One drug interferes with the action of another is
a. Synergistic effect
b. Antagonistic effect
c. Additive effect
d. Displacement
The combined effect of two drugs is greater than the sum of the effect of each drug
given alone.
a. Synergistic effect
b. Antagonistic effect
c. Additive effect
d. Displacement
The second drug increases the activity of the first drug is
a. Synergistic effect
b. Antagonistic effect
c. Additive effect
d. Displacement
One drug inhibit the metabolism of excretion of a second drug, causing increased
activity of the second drug is
a. Synergistic effect
b. Interference
c. Incompatibility
d. Displacement
This cause deterioration when the two drugs are mixed in the same syringe or solution
a. Synergistic effect
b. Interference
c. Incompatibility
d. Displacement
Essay:
1. Differentiate idiosyncratic reaction to allergic reaction:
Idiosyncratic reactions are drug reactions that occurs when something unusual or abnormal
happens when a drug is administered and occurs unpredictably and rarely among the population
or do not occur in most patients at any dose. The patient usually shows an overresponse to the
action of the drug. And it is usually due to a patient’s inability to metabolize a drug because of a
genetic deficiency of certain enzymes. While Allergic reaction occurs in patients who have
previously been exposed to a drug and have developed antibodies to it from their immune system.
The immune system will defend against substances that typically don’t pose a threat to the human
body which are known as allergens, and when your body reacts to them, then it will cause an
allergic reaction. It is also known as hypersensitivity reaction and occurs in about 6-10% of patients
taking medications.
2. Explain the factors that cause variations in absorption, distribution, metabolism and
excretion of drugs.
When a person swallow a tablet or apply cream on the skin, the first thing that takes place is
Absorption, the drug has to absorb and once it gets to absorbed either through skin or stomach it
gets to the blood stream for distribution around the body. The rate at which this occurs depends on
the route of administration, the blood flow through the tissue where the drug is administered, and
the solubility of the drug. Like in an oral dose it is a lengthy process, during which drug molecules
may be damaged like denatured by gastric acid, sequestered like bound to food preventing
absorption or modified by first-pass metabolism, so as results of all these hazards, absorption is
frequently incomplete following oral administration.
Distribution is the way in which a drug is transported throughout the body by the circulating body
fluids to the sites of action or to the receptors that the drug affects. Organs with the most extensive
blood supplies like heart, liver, kidneys, brain receive the distributed drug most rapidly. And areas
with less extensive blood supplies like muscle, skin, fat will receive the drug more slowly. After a
drug has been dissolved and absorbed into the circulating blood, its distribution is determined by
the chemical properties of the drug and how it is affected by the blood and tissues that it contacts.
And the factors that affect drug distribution are protein binding and lipid solubility. Unbound drugs
pass freely through blood vessels and is distributed into the rest of the body. Drugs that are bound
to plasma proteins are pharmacologically inactive because the large size of the complex keeps
them in the bloodstream and prevents them from reaching the sites of action, metabolism, and
excretion. To make it simpler, small drug molecules can freely diffuse out of the blood vessel
while large drug molecules are confined to the plasma.
So once the drug gets distributed all over the body. The body starts metabolizing it, this is done
primarily by a liver it basically modifies the drug so that it is easy to secrete, but it can also be
done by other tissues. The enzyme systems of the liver are the primary sites for the metabolism of
drugs, but other tissues and organs such as white blood cells, GI tract, lungs metabolize certain
drugs to a minor extent. The rate of drug metabolism varies widely between individuals, influenced
by genetic and environmental factors. This is the major reason for interindividual differences in
the plasma concentration of some drugs after a standard dose, which leads to wide variation in
drug response. Because individuals vary significantly in their clinical responses to administered
drugs and the outcomes, which can be inherited or acquired, are always patient-specific. Such
interindividual variation is often a challenge to optimizing a dosage regimen because most drugs
are effective in only to some patients. Different patients can respond differently to the same drug
and dose. Sometimes, the effective drug dose for a particular patient may prove lethal to or result
in therapeutic failure in others leading to serious adverse effects or no effects at all.
Elimination is the last step in which drug and its metabolites gets excreted primarily in bile urine
and feces. They may leave through the GI tract into the feces and through the renal tubules into
the urine. Other routes of excretion include evaporation through the skin, exhalation from the
lungs, and secretion into saliva and breast milk. Because the kidneys are major organs of drug
excretion, the patient's chart for the results of urinalysis and renal function tests should be
reviewed. A patient with renal failure often has an increase in the action and duration of a drug if
the dosage and frequency of administration are not adjusted to allow for the patient's reduced renal
function.
3. What are the sources of drug information?
The sources of drug information are USP Dictionary of United States Adopted Names (USAN)
and International Drug Names, American Drug Index, AHFS Drug Information, Drug Interaction
Facts, Drug Facts and Comparisons, ASHP's Handbook on Injectable Drugs: IV Decision Support,
Handbook of Nonprescription Drugs: An Interactive Approach to Self-Care, Martindale: The
Complete Drug Reference, Physicians' Desk Reference (PDR), Natural Medicines Comprehensive
Database, LactMed (Drugs and Lactation Database), Developmental and Reproductive
Toxicology Database (DART).
