D441 Medical Dosage Calculations and
Pharmacology Chapter 2 Pharmacological
Principles Questions With Correct Answers
Explain the relationship with potassium and digoxin.
| | | | | |
Digoxin competes for binding sites with potassium on the sodium-
| | | | | | | | |
potassium ATPase pump. Here's how it works:
| | | | | |
1. Binding Sites: The sodium-potassium ATPase pump has specific sites
| | | | | | | | | |
where potassium ions usually bind to be transported into the cell.
| | | | | | | | | |
2. Competition: Digoxin competes with potassium for these binding
| | | | | | | | |
sites. When digoxin binds to the pump, it inhibits its function,
| | | | | | | | | | |
preventing potassium from entering the cell and sodium from leaving
| | | | | | | | | |
the cell.
|
This competition is why low potassium levels (hypokalemia) can
| | | | | | | | |
increase the effects of digoxin, as there are fewer potassium ions to
| | | | | | | | | | | |
compete with digoxin for those binding sites. Conversely, high
| | | | | | | | |
potassium levels (hyperkalemia) can reduce the effects of digoxin
| | | | | | | | |
because more potassium ions are available to compete with digoxin for
| | | | | | | | | | |
binding to the pump. | | |
,All topical routes of drug administration avoid first-pass effects of the
| | | | | | | | | | |
liver, except:
|
Rectal administration. Because it is part of the GI tract, some drug will
| | | | | | | | | | | | |
be absorbed into the capillaries that feed the portal vein to the liver.
| | | | | | | | | | | |
Depot Drugs |
Specifically formulated long-acting IM dosage forms; designed for slow
| | | | | | | | |
absorption over a period of several days to months. Example: invega
| | | | | | | | | |
Blood-brain barrier |
Blood vessels (capillaries) that selectively let certain substances enter
| | | | | | | | |
the brain tissue and keep other substances out.
| | | | | | |
How does the lipophilicity of a drug affect its metabolism and excretion?
| | | | | | | | | | |
What role does the liver play in this process?
| | | | | | | | |
Lipophilicity, or the ability of a drug to dissolve in fats, affects its
| | | | | | | | | | | | |
metabolism and excretion in several ways:
| | | | |
, 1. Absorption and Distribution: Lipid-soluble drugs are readily absorbed
| | | | | | | | |
through cell membranes, which are composed of lipid bilayers. Once
| | | | | | | | | |
absorbed, these drugs are widely distributed throughout the body,
| | | | | | | | |
particularly in fatty tissues. | | |
2. Metabolism: The liver plays a crucial role in metabolizing lipid-soluble
| | | | | | | | | | |
drugs. The liver converts these drugs into more water-soluble
| | | | | | | | |
metabolites through processes like oxidation, reduction, and
| | | | | | |
conjugation. This transformation is essential because it makes the drugs
| | | | | | | | | |
easier to excrete.
| |
3. Excretion: Once metabolized, the water-soluble metabolites are
| | | | | | | |
excreted through the kidneys in urine or through the bile in feces.
| | | | | | | | | | | |
Because lipid-soluble drugs are stored in fat tissues, they can be
| | | | | | | | | | |
released slowly over time, leading to prolonged effects and a longer
| | | | | | | | | | |
presence in the system. | | |
Overall, the liver's metabolic processes are vital for transforming lipid-
| | | | | | | | |
soluble drugs into forms that can be efficiently excreted from the body.
| | | | | | | | | | |
How does p-glycoprotein affect drug metabolism?
| | | | |
P-glycoprotein (P-gp) is a crucial player in drug metabolism and
| | | | | | | | | |
transport. It's a type of efflux transporter protein found in cell
| | | | | | | | | | |
Pharmacology Chapter 2 Pharmacological
Principles Questions With Correct Answers
Explain the relationship with potassium and digoxin.
| | | | | |
Digoxin competes for binding sites with potassium on the sodium-
| | | | | | | | |
potassium ATPase pump. Here's how it works:
| | | | | |
1. Binding Sites: The sodium-potassium ATPase pump has specific sites
| | | | | | | | | |
where potassium ions usually bind to be transported into the cell.
| | | | | | | | | |
2. Competition: Digoxin competes with potassium for these binding
| | | | | | | | |
sites. When digoxin binds to the pump, it inhibits its function,
| | | | | | | | | | |
preventing potassium from entering the cell and sodium from leaving
| | | | | | | | | |
the cell.
|
This competition is why low potassium levels (hypokalemia) can
| | | | | | | | |
increase the effects of digoxin, as there are fewer potassium ions to
| | | | | | | | | | | |
compete with digoxin for those binding sites. Conversely, high
| | | | | | | | |
potassium levels (hyperkalemia) can reduce the effects of digoxin
| | | | | | | | |
because more potassium ions are available to compete with digoxin for
| | | | | | | | | | |
binding to the pump. | | |
,All topical routes of drug administration avoid first-pass effects of the
| | | | | | | | | | |
liver, except:
|
Rectal administration. Because it is part of the GI tract, some drug will
| | | | | | | | | | | | |
be absorbed into the capillaries that feed the portal vein to the liver.
| | | | | | | | | | | |
Depot Drugs |
Specifically formulated long-acting IM dosage forms; designed for slow
| | | | | | | | |
absorption over a period of several days to months. Example: invega
| | | | | | | | | |
Blood-brain barrier |
Blood vessels (capillaries) that selectively let certain substances enter
| | | | | | | | |
the brain tissue and keep other substances out.
| | | | | | |
How does the lipophilicity of a drug affect its metabolism and excretion?
| | | | | | | | | | |
What role does the liver play in this process?
| | | | | | | | |
Lipophilicity, or the ability of a drug to dissolve in fats, affects its
| | | | | | | | | | | | |
metabolism and excretion in several ways:
| | | | |
, 1. Absorption and Distribution: Lipid-soluble drugs are readily absorbed
| | | | | | | | |
through cell membranes, which are composed of lipid bilayers. Once
| | | | | | | | | |
absorbed, these drugs are widely distributed throughout the body,
| | | | | | | | |
particularly in fatty tissues. | | |
2. Metabolism: The liver plays a crucial role in metabolizing lipid-soluble
| | | | | | | | | | |
drugs. The liver converts these drugs into more water-soluble
| | | | | | | | |
metabolites through processes like oxidation, reduction, and
| | | | | | |
conjugation. This transformation is essential because it makes the drugs
| | | | | | | | | |
easier to excrete.
| |
3. Excretion: Once metabolized, the water-soluble metabolites are
| | | | | | | |
excreted through the kidneys in urine or through the bile in feces.
| | | | | | | | | | | |
Because lipid-soluble drugs are stored in fat tissues, they can be
| | | | | | | | | | |
released slowly over time, leading to prolonged effects and a longer
| | | | | | | | | | |
presence in the system. | | |
Overall, the liver's metabolic processes are vital for transforming lipid-
| | | | | | | | |
soluble drugs into forms that can be efficiently excreted from the body.
| | | | | | | | | | |
How does p-glycoprotein affect drug metabolism?
| | | | |
P-glycoprotein (P-gp) is a crucial player in drug metabolism and
| | | | | | | | | |
transport. It's a type of efflux transporter protein found in cell
| | | | | | | | | | |
