TUTORIAL ON GENERAL PRINCIPLES OF PHARMACOLOGY

DR VENKATA SUBBA REDDY A

PG IN PHARMACOLOGY

ANDHRA MEDICAL COLLEGE

VISAKHAPATNAM

A. Enteral B. Intramuscular C. Intrathecal D. IntravenousE. Transdermal

A 79-year-old man with end-stage Alzheimer’s disease and dysphagia is taking multiple medications. Physical examination reveals xerostomia and a limited gag reflex. Which of the following routes of medication administration would provide the lowest serum drug concentration?

Dysphagia and Alzheimer’s disease. Would make drug administration by mouth difficult and limit direct absorption

via the stomach.Give the lowest serum drug concentrations

(B) Intramuscular administration, although painful for the patient, would give acceptable serum drug concentrations.

(C) Intrathecal administration would give acceptable therapeutic drug concentrations but would be limited to CNS disease states.

(D) Intravenous administration would provide medications via vein and therapeutic drug concentrations. It could be used for various medications.

(E) Transdermal administration applies medications to the skin and could achieve therapeutic drug concentrations

A. AbsorptionB. DistributionC. EliminationD. GlycosylationE. Metabolism

A 28-year-old man with seborrheic dermatitis is prescribed a topical corticosteroid crème by his dermatologist in hopes of alleviating the chronic rash and erythema on the cheeks. Which of the following steps is most critical to achieve a therapeutic drug concentration in plasma?

Drug absorption from the site of administration, in this case via the topical route, allows the medication to enter into the skin and then into the plasma. Following this step, the medication can distribute into tissues and also be metabolized in tissues.

(B) Distribution occurs following absorption of the drug from the site of administration.

(C) Elimination involves removal of the drug from the body via urine, bile, or feces.

(D) Glycosylation is not a step in the process of drug pharmacokinetics. (E) Metabolism of drugs occurs in the kidneys or liver after the drug has

achieved adequate levels in tissues.

A. InhalationB. Intranasal puff metered doseC. SubcutaneousD. SublingualE. Topical

A 31-year-old man is brought to the emergency department complaining of dyspnea. He has a history of asthma and has had multiple asthma attacks requiring intubation for airway maintenance. He is noncompliant with his medications prescribed for this condition. Physical examination reveals a young man in acute distress. His room air oxygen saturation is 87%. In addition to administration of oxygen, immediate drug administration of albuterol should be administered by which of the following routes?

Inhalation provides rapid delivery of a drug across a large surface area of the respiratory tract and is the route of administration of choice in a patient with an airway disease such as asthma. Inhaled albuterol is commonly administered in this manner.

(B) Intranasal puff metered dose would only deliver a small amount of drug to the patient and would not be recommended in this acutely ill patient.

(C) Subcutaneous administration is a slow route of administration and is not preferred in this acutely ill patient.

(D) Sublingual, although allowing the medication to enter the circulation would be less preferred than the inhalation route in this acutely ill patient.

(E) Topical administration would only achieve a local effect of the drug and is contraindicated in this acutely ill patient.

A 48-year-old-man with end-stage liver disease is hospitalized on the intensive care unit. Review of his blood work reveals elevated liver function tests to five times the normal rate. The patient is receiving multiple intravenous medications. Which of the following medications is likely to be therapeutic for this patient?

A. EpinephrineB. ErythromycinC. NifedipineD. RifampinE. Verapamil

This patient has endstage liver disease. This ability to metabolize medications through the cytochrome system of the liver is impaired. Drugs that are metabolized in this fashion will not be properly broken down and will accumulate to toxic levels. Epinephrine is not metabolized by the cytochrome system and can be used with caution in this patient.

(B) Erythromycin is an antibiotic metabolized by the hepatic cytochrome system.

(C) Nifedipine is an antihypertensive metabolized by the hepatic cytochrome system.

(D) Rifampin is used in the treatment of tuberculosis and is also metabolized by the hepatic cytochrome system.

(E) Verapamil is a calcium channel blocker and is also metabolized by the hepatic cytochrome system.

A hospitalized patient with systemic candidiasis is receiving intravenous antifungal medications. He also has hepatic and renal insufficiency. Which of the following drug administration schemes would allow for the most steady state amount of drug in the body over a 2-week hospitalization period where medication administration will be necessary ?

A. Continuous IV infusionB. Once weekly IV injectionC. Single daily IV injectionD. Twice daily IV injectionE. Twice weekly IV injection

Continuous IV infusion results in a less rapid influx of drug into the body initially. However, within a short time, a steady state of drug level in the body will be achieved. Although the drug level will achieve steady state, injection of drugs several times daily will result in higher drug amounts initially after dosing but will decrease according to half-life.

(B) Once weekly IV injection will result in a peak and trough level of the drug with initially high concentrations and will decrease to almost no drug in the system.

(C) Single daily IV injections result in lower amounts of drug in the body with peaks and troughs.

(D) Twice daily IV injections will result in the highest amounts of drug in the body but will also have peaks and troughs.

(E) Twice weekly IV injections will result in higher amounts of drug in the body as compared with once weekly IV injections.

A 27-year-old man with HIV disease and hepatic insufficiency presents to his primary care physician complaining of rectal pain and bleeding with bowel movements. Physical examination reveals several internal and external hemorrhoids. The patient would like to avoid surgical therapy for this condition. Which of the following routes of drug administration would be preferred in this patient?

A. EnteralB. IntramuscularC. IntravenousD. RectalE. Transdermal

This patient has hemorrhoids, and a topical route of administration of medication is preferred. This route avoids the hepatic first pass effect so the patient’s liver insufficiency would not likely be problematic with this route of administration.

(A) Enteral route administration will be unlikely to achieve an adequate therapeutic response in a patient with hemorrhoids.

(B) Intramuscular route administration is an ineffective therapy for rectal diseases.

(C) Intravenous administration is an ineffective therapy for rectal diseases such as hemorrhoids.

(E) Transdermal administration achieves systemic effects through systemic absorption of medication. It is not effective for internal hemorrhoids.

A drug that binds to a receptor and produces a biological response that mimics the response to the endogenous ligand is known as

A. AgonistB. AntagonistC. Functional antagonistD. Partial agonistE. Partial antagonist

The definition of an agonist is the biologic response produced by a drug binding to its receptor. For example, the a-adrenergic agonist phenylephrine when it binds to its receptor produces responses similar to the endogenous ligand.

(B) Antagonists are drugs that decrease the actions of another drug or the endogenous ligand.

(C) Functional antagonists may act at a separate receptor and oppose those effects of the agonist.

(D) Partial agonists have activities somewhere between the full agonist and no agonistic activity.

(E) Partial antagonists have activities somewhere between the full antagonist and no antagonistic activity.

A 22-year-old woman who is afraid of running into her former boyfriend actually meets him unexpectedly in a shopping mall. Her fears are because their former relationship was marked by physical and mental abuse. Memories of him are met with increased anxiety and fear. Which of the following physiologic responses would this woman be expected to exhibit at this time of seeing this man?

A. BradycardiaB. DiarrheaC. HypertensionD. Sweating E. Tracheal deviation

This patient is exhibiting features of the “fight-or-flight” response, which is triggered by sympathetic activation. The cardiac effects include increased heart rate, contractility, and blood pressure. Skeletal muscle blood vessels dilate while skin blood vessels vasoconstrict.

(A) This patient will exhibit tachycardia. (B) This patient will exhibit increased gastrointestinal sphincter tone. (D) This patient will have vasoconstriction of the skin and mucous

membranes. (E) Tracheal dilation, not deviation occurs in the “fight-or-flight” response.

A 15-year-old boy who has diabetes and is insulin dependent is brought to the emergency department after collapsing at a baseball game. His blood sugar is 463 mg/dL by finger stick. Which of the following routes of administration would be most efficacious for medications to bring the blood sugar down?

A. IntramuscularB. IntravenousC. OralD. SubcutaneousE. Sublingual

Insulin (as most drugs) needs to enter the bloodstream for maximal effect; IV infusion will result in the fastest and highest peak blood insulin concentration. There are many formulations of insulin for intramuscular or subcutaneous injection, but even the fastest have no effect until the insulin reaches the systemic blood circulation. There is no way to make insulin absorption into the blood from intramuscular or subcutaneous injection faster than injecting directly into the blood. The same can be said for inhaled and sublingual insulin preparations.

(A) Intramuscular insulin can be given in rapidly acting formulations, but even this is not as fast as IV insulin.

(C) Insulin given orally would be broken down and rendered ineffective by peptidases in the gut.

(D) Subcutaneous insulin can be given in rapidly acting formulations, but even this is not as fast as IV insulin.

(E) Insulin is not normally given sublingually, and sublingual absorption is slower than IV infusion.

A researcher is studying the bioavailability of commonly used antimuscarinics to treat irritable bowel syndrome. Medication A is administered in a 100 mg daily dose orally and 60 mg of the drug is absorbed from the gastrointestinal tract unchanged. Thus, the bioavailability of Medication A is

A. 50% B. 60%C. 70%D. 80%E. 90%

Medication A has a bioavailability of 60%. Bioavailability is the fraction of administered drug that reaches the systemic

circulation. In this example, if 100 mg of Medication A is administered orally, and 60 mg

of this drug is absorbed unchanged, the bioavailability is 0.6, or 60%. Determining bioavailability is important for calculating drug dosages for

various routes of administration other than the intravenous route.