Pharmacotherapy Exam 1 September 27: Lecture 1 - Pharmacokinetics, ETC

1. The definition of absorption tells us that the drug is absorbed when it reaches:

The bloodstream

The target organ

The site of lipid, bone or other organ storage

As stated in handout

Explanation

As stated in handout

2. Given that a specific drug's maximum effect is reached prior to occupation of all available receptors, what risk is associated with stimulation of the "spare receptors"?

Toxicity

Higher therapeutic index

Stimulation of "spare receptors" can lead to toxicity. This occurs when the drug continues to bind to and stimulate these spare receptors even after the maximum effect has been reached. As a result, excessive stimulation can occur, leading to adverse effects and potential toxicity.

Explanation

Stimulation of "spare receptors" can lead to toxicity. This occurs when the drug continues to bind to and stimulate these spare receptors even after the maximum effect has been reached. As a result, excessive stimulation can occur, leading to adverse effects and potential toxicity.

3. Drug solubility to cross membranes: when the drug is in stomach acid, it will pass through the stomach walls best if it is an acidic drug, neutral drug, or alkaline drug?

Alkaline

Acidic

Neutral

In the acidic environment of the stomach, an acidic drug becomes uncharged and lipid-soluble, thereby able to cross the stomach walls whose cell membranes are phospholipid.

Explanation

In the acidic environment of the stomach, an acidic drug becomes uncharged and lipid-soluble, thereby able to cross the stomach walls whose cell membranes are phospholipid.

4. Levodopa is described as a drug that does not act by stimulation of a receptor. Its action instead is that it is converted to what neurotransmitter?

Levodopa is a drug that is converted to dopamine, a neurotransmitter, in the brain. It is commonly used in the treatment of Parkinson's disease, as it helps to increase dopamine levels in the brain, compensating for the deficiency caused by the disease. By increasing dopamine levels, levodopa helps to improve movement and reduce the symptoms of Parkinson's disease. Therefore, the correct answer is dopamine.

Explanation

Levodopa is a drug that is converted to dopamine, a neurotransmitter, in the brain. It is commonly used in the treatment of Parkinson's disease, as it helps to increase dopamine levels in the brain, compensating for the deficiency caused by the disease. By increasing dopamine levels, levodopa helps to improve movement and reduce the symptoms of Parkinson's disease. Therefore, the correct answer is dopamine.

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5. When therapeutic index is high, the margin of safety is:

High

Low

When the therapeutic index is high, it means that the effective dose of a drug is significantly lower than the toxic dose. This indicates that there is a wide margin of safety between the therapeutic dose and the dose that could potentially cause harm or toxicity. In other words, a high therapeutic index suggests that the drug is relatively safe to use, as the chances of experiencing adverse effects are low compared to the desired therapeutic effects.

Explanation

When the therapeutic index is high, it means that the effective dose of a drug is significantly lower than the toxic dose. This indicates that there is a wide margin of safety between the therapeutic dose and the dose that could potentially cause harm or toxicity. In other words, a high therapeutic index suggests that the drug is relatively safe to use, as the chances of experiencing adverse effects are low compared to the desired therapeutic effects.

6. Efficacy vs Potency - Which term evaluates the dose required to reach ED₅₀ and which term relates to the maximum response of a drug?

Potency relates dose amount to ED50, efficacy relates to maximum response

Efficacy relates dose amount to ED50, potency relates to maximum response

Potency refers to the dose amount required to reach ED50, which is the effective dose that produces a response in 50% of the population. On the other hand, efficacy relates to the maximum response that a drug can produce. In other words, potency measures the strength or concentration of a drug needed to achieve a certain effect, while efficacy measures the extent or magnitude of the effect that the drug can produce.

Explanation

Potency refers to the dose amount required to reach ED50, which is the effective dose that produces a response in 50% of the population. On the other hand, efficacy relates to the maximum response that a drug can produce. In other words, potency measures the strength or concentration of a drug needed to achieve a certain effect, while efficacy measures the extent or magnitude of the effect that the drug can produce.

7. Most drugs cross cell membranes by which means of transport:

Pinocytosis

Non-ionized passive diffusion

Filtration through pores

Ionized active diffusion

Ionized passive diffusion

As stated in handout

Explanation

As stated in handout

8. LD₅₀ is

Dose amount that killed 50% of the people in development of the drug

Dose that kills 50% of animals given the drug

Dose needed to ensure the desired effect in at least half of the subjects

LD50 refers to the dose that kills 50% of animals given the drug. It is a measure used in toxicology to determine the lethal dose of a substance. The LD50 value provides information about the toxicity of a drug or chemical and helps in assessing its safety. By determining the dose that kills 50% of the animals, researchers can establish the potential harm or lethality of a substance.

Explanation

LD50 refers to the dose that kills 50% of animals given the drug. It is a measure used in toxicology to determine the lethal dose of a substance. The LD50 value provides information about the toxicity of a drug or chemical and helps in assessing its safety. By determining the dose that kills 50% of the animals, researchers can establish the potential harm or lethality of a substance.

9. The drug class of drug NOT stimulating receptors but rather by inhibiting ion channels to affect electrical properties of certain cells?

Anesthetics, both local and general, do not stimulate receptors but instead work by inhibiting ion channels to alter the electrical properties of specific cells. This mechanism of action allows them to block nerve signals and induce a loss of sensation or consciousness. By interfering with the flow of ions across cell membranes, anesthetics disrupt the normal electrical activity necessary for nerve transmission, resulting in their desired effects.

Explanation

Anesthetics, both local and general, do not stimulate receptors but instead work by inhibiting ion channels to alter the electrical properties of specific cells. This mechanism of action allows them to block nerve signals and induce a loss of sensation or consciousness. By interfering with the flow of ions across cell membranes, anesthetics disrupt the normal electrical activity necessary for nerve transmission, resulting in their desired effects.

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10. An enteric-coated drug differs from a time-release form of the drug by which physical differences and which differences in purpose, given that both are taken orally? (Freeform answer, so it can not really be gotten correct)

Enteric-coated drugs have a protective wax coating that prevents them from being destroyed by stomach acids. This coating only dissolves in the alkaline environment of the duodenum, allowing the drug to be absorbed effectively. This is particularly important for drugs such as hormones and proteins that would be broken down in the acidic environment of the stomach. On the other hand, time-release forms of drugs are designed to release the drug slowly over an extended period of time. This can be achieved through various physical designs, such as microspheres that dissolve slowly or release the drug without dissolving. This method is commonly used for drugs with short half-lives to reduce the frequency of dosing.

Explanation

Enteric-coated drugs have a protective wax coating that prevents them from being destroyed by stomach acids. This coating only dissolves in the alkaline environment of the duodenum, allowing the drug to be absorbed effectively. This is particularly important for drugs such as hormones and proteins that would be broken down in the acidic environment of the stomach. On the other hand, time-release forms of drugs are designed to release the drug slowly over an extended period of time. This can be achieved through various physical designs, such as microspheres that dissolve slowly or release the drug without dissolving. This method is commonly used for drugs with short half-lives to reduce the frequency of dosing.

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