Pharm Exam 4 Prototype Questions (36, 37, 48, 49, 14, 15, 16)

What are the therapeutic and pharmacological classes of isoniazid?

T: Antituberculosis drug

P: Mycolic acid inhibitor

What is the mechanism of action of isoniazid?

It is a first-line drug for M. tuberculosis. Acts by inhibiting the synthesis of mycolic acids, essential components of mycobacteria cell walls.

What does isoniazid do to actively growing organisms and dormant mycobacteria in the body?

It is bactericidal for actively growing organisms but bacteriostatic for dormant mycobacteria.

How many patients develop resistance to isoniazid during long term therapy?

10% of patients

What are the administration alerts for isoniazid?

-give on an empty stomach; 1 hr after or 2 hrs before meals.

-inject deep IM and rotate sites.

-has not shown fetal harm above baseline levels or adverse effects for breastfed neonates.

What is the onset, peak, and duration of isoniazid?

Onset: 30 min

Peak: 1-2 h

Duration: 6-8 h

What are the adverse effects of isoniazid?

-numbness of hands and feet

-rash

-fever

-neurotoxicity

-convulsions

What is the Black Box warning for isoniazid?

Hepatotoxicity; pts should be monitored for jaundice, fatigue, elevated hepatic enzymes (usually performed monthly), or loss of appetite. Older adults who drink alcohol daily are at a higher risk of developing hepatotoxicity.

When/to whom is it contraindicated to administer isoniazid?

-Patients with hypersensitivity to the drug

-Patients with severe hepatic impairment

What drug-to-drug interactions can occur with isoniazid?

-aluminum-containing antacids: should not be administered concurrently bc they can decrease the absorption of isoniazid.

-disulfiram: concurrent use may result in lack of coordination or psychotic reactions.

-alcohol: consumption concurrently with isoniazid increases the risk of hepatotoxicity.

-phenytoin & carbamazepine: serum levels may increase when isoniazid is administered.

What herbal/food interactions may occur with isoniazid use?

-Food interferes with the absorption of isoniazid.

-Tyramine-containing foods may increase isoniazid toxicity.

What are the characteristics and treatment of isoniazid overdose?

Characterized by recurrent seizures, profound metabolic acidosis, and coma. May be fatal.

Treatment: Pyridoxine (Vit B6) may be infused in a dose equal to that of the isoniazid overdose to prevent seizures and correct metabolic acidosis.

What are the therapeutic and pharmacological classes of amphotericin B?

T: Antifungal (systemic type)

P: Polyene

What is the mechanism of action of amphotericin B?

It acts by binding to ergosterol in fungal cell membranes, causing them to become permeable or leaky.

How does amphotericin B work against bacteria?

It has a broad spectrum of activity and is effective against most pathogenic fungi.

What is amphotericin B used for?

It has been the traditional drug for serious systemic mycoses. It may also be indicated as prophylactic antifungal therapy for patients with severe immunosuppression.

Why is amphotericin B administered via IV infusion?

It is not absorbed from the GI tract.

How is the toxicity of amphotericin B reduced?

The original drug molecule has been formulated with two different types of lipid "delivery vehicles". Lipid formulations reduce nephrotoxicity and result in less infusion-related fever and chills. Reduced toxicity is believed to be due to the decreased plasma levels of the drug.

What are the two delivery vehicles for amphotericin B and what are they?

-Liposomal amphotericin B: consists of closed spherical vesicles. Amphotericin B is integrated into the lipid membrane.

-Amphotericin B lipid complex: contains amphotericin B complexed with two phospholipids in a 1:1 ratio.

Why are lipid preparations used less frequently?

They are expensive so they are generally used only after therapy with other antifungals has failed.

What are the administration alerts for amphotericin B?

-infuse slowly because CV collapse may result if the medication is infused too rapidly.

-Admin. premedication (acetaminophen, antihistamines, and corticosteroids) to decrease the risk of hypersensitivity reactions.

-Withhold the drug if the BUN exceeds 40 mg/dL or serum creatinine rises above 3 mg/dL.

-Human experience during pregnancy is limited; data has not shown evidence of fetal harm or adverse effects on the breastfed neonate.

What is the onset, peak, and duration of amphotericin B?

Onset: immediate IV

Peak: 1-2 h

Duration: 20 h (may persist several weeks after therapy has ended)

What are the adverse effects of amphotericin administration?

-fever

-chills

-vomiting

-headache

-phlebitis

-nephrotoxicity in 80% of pt.'s and electrolyte imbalances (hypokalemia)

What should nurses assess for when administering amphotericin B?

Hearing loss, vertigo, unsteady gait, or tinnitus because ototoxicity may occur.

When/to whom is it contraindicated to administer amphotericin B?

Pt.'s with a hypersensitivity to the drug.

When/with whom should caution be used with amphotericin B administration?

Pt.'s with CKD.

What drug-to-drug interactions may occur with amphotericin B administration?

-Concurrent use with drugs that reduce kidney function (aminoglycosides, vancomycin, or carboplatin) is not recommended.

-Concurrent use with corticosteroids, skeletal muscle relaxants, and thiazole may potentiate hypokalemia.

-Concurrent use with digoxin increases the risk of digoxin toxicity in patients with preexisting hypokalemia.

What herbal/food interactions may occur with amphotericin B administration?

Interactions are unknown.

What are the characteristics and treatment of amphotericin B overdose?

Characteristics include cardiorespiratory arrest, severe renal, cardiac, and electrolyte imbalances.

Treatment does not consist of specific therapy; pt.'s are treated symptomatically.

What are the therapeutic and pharmacologic classes of Fluconazole?

T: Antifungal

P: Inhibitor of fungal cell membrane synthesis; azole

What is the mechanism of action of Fluconazole?

Acts by interfering with the synthesis of ergosterol. It is able to penetrate most body membranes to reach infections in the central nervous system, bone, eye, urinary tract, and respiratory tract.

What is the most advantageous route of administration of Fluconazole?

It is rapidly and completely absorbed when it is given PO, and is particularly effective against Candida albicans.

When is Fluconazole use disadvantageous?

It has a relatively narrow spectrum of activity, not as effective against non-albicans Candida species, which account for a significant percentage of opportunistic fungal infections.

When is Fluconazole approved for prophylaxis use?

Prophylaxis of fungal infections in patients with AIDS, those undergoing bone marrow transplants, and those receiving antineoplastic drugs.

What are the administration alerts for Fluconazole administration?

-Do not mix IV fluconazole with other drugs.

-Causes fetal harm at high doses and increases the risk for spontaneous abortion. Should not be used during pregnancy or lactation unless the potential benefits to the mother justify the potential risks to the fetus/neonate.

What is the onset, peak, and duration of Fluconazole administration?

Onset: Rapid IV; unknown PO

Peak: 1h IV; 1-2 h PO

Duration: 2-4 days

What are the adverse effects of fluconazole administration?

-nausea

-vomiting

-diarrhea

-hepatotoxicity is rare but should be assessed for in pt.'s with hepatic impairment

-SJS has been reported in pt.'s with immunosuppression

When/to whom is it contraindicated to administer fluconazole?

Patients with hypersensitivity to the drug.

When/with whom should fluconazole be used with caution?

Patients with CKD.

What drug-to-drug interactions may occur with fluconazole administration?

-Concurrent use with warfarin increases the risk for bleeding.

-Concurrent use with certain oral hypoglycemics (e.g. glyburide) may result in hypoglycemia.

-Concurrent use with rifampin or cimetidine may result in decreased fluconazole levels.

-Concurrent use with fentanyl, alfentanil, or methadone may result in prolonged effects (of those drugs).

What herbal/food interactions may occur with fluconazole administration?

Interactions are unknown.

What are the characteristics and treatment of fluconazole overdose?

Characteristics include mental changes and hallucinations.

Treatment is not specific for overdose. Dialysis can be used to lower the serum drug level.

What are the therapeutic and pharmacologic classes of Nystatin?

T: Superficial antifungal

P: Polyene

What is the mechanism of action of nystatin?

It binds to sterols in the fungal cell membrane, causing leakage of intracellular contents as the membrane becomes weakened.

When is nystatin used?

Candida infections of the vagina, skin, and mouth. Oropharyngeal candidiasis. Candidiasis of the intestine (bc it travels through the GI tract without being absorbed).

What are the administration alerts for nystatin?

-For oral candidiasis, apply with a swab to the affected area in infants and children bc swishing is difficult or impossible.

-For adults with oral candidiasis, the drug should be swished in the mouth for at least 2 min.

-Not known if the drug adversely affects pregnancy or lactation. Pt should check with provider prior to use.

What is the onset, peak, and duration of nystatin?

Onset: Rapid

Peak: Unknown

Duration: 6-12 h

What are the adverse effects of nystatin administration?

-contact dermatitis

-diarrhea

-nausea

-vomiting

When/to whom is nystatin administration contraindicated?

Patients with hypersensitivity to the drug.

What drug-to-drug interactions may occur with nystatin administration?

Unknown

What herbal/food interactions may occur with nystatin administration?

Unknown

What are the characteristics and treatment of nystatin overdose?

Characteristics include stomach bloating or pain, nausea, or vomiting. Treatment is not specific.

What are the therapeutic and pharmacologic classes of Metronidazole?

T: Anti-infective, antiprotozoan

P: drug that disrupts nucleic acid synthesis

What is metronidazole used for?

-It has antibiotic activity against anaerobic bacteria, so it is used to treat a number of respiratory, bone, skin, and CNS infections. -Topical forms are used to treat rosacea, a disease characterized by reddening and hyperplasia of the sebaceous glands, particularly around the nose and face.

-Helidac (combo drug consisting of metronidazole, bismuth, and tetracycline) is used to eradicate H. pylori infection associated with PUD

What is metronidazole a preferred drug for?

Giardiasis and trichomoniasis.

What is the off-label use metronidazole?

The pharmacotherapy of pseudomembranous colitis and Crohn disease.

What are the administration alerts for metronidazole?

-The ER form must be swallowed whole and taken on an empty stomach.

-PO or parenteral forms may cause fetal harm if taken during the first trimester. Systemic metronidazole should be given during pregnancy only if the potential benefits to the mother justify the potential risks to the fetus.

What is the onset, peak, and duration of metronidazole?

Onset: Rapid

Peak: 1-3 h

Duration: 6-8 h

What are the adverse effects of metronidazole administration?

-anorexia

-nausea

-diarrhea

-dizziness

-headache

-dryness of mouth and metallic taste

-bone marrow suppression

What is the Black Box warning for metronidazole?

It is a carcinogenic in lab animals and should only be used for approved indications.

When/to whom is metronidazole administration contraindicated?

-Patients with trichomoniasis during the first trimester of pregnancy and those with hypersensitivity to the drug.

-Patients with blood dyscrasias bc it can cause bone marrow suppression.

What drug-to-drug interactions may occur with metronidazole administration?

-Concurrent use with oral anticoagulants potentiates hypoprothrombinemia.

-Concurrent use with alcohol, or other medications containing alcohol may elicit a disulfiram reaction.

-Concurrent use with lithium may cause elevated lithium levels.

What herbal/food interactions may occur with metronidazole administration?

Interactions are unknown

What are the characteristics and treatment of metronidazole overdose?

Characteristics of overdoes include GI symptoms (N/D/V, abdominal pain/cramping) and CNS symptoms (peripheral neuropathy, seizure, ataxia). Treatment of overdose does not consist of a specific treatment.

What is the therapeutic and pharmacologic class of Mebendazole?

T: Drug for worm infections

P: Antihelminthic

What is mebendazole used for?

The most widely prescribed antihelminthic in the US used in the treatment of a wide range of helminth infections (inc. roundworm and pinworm). Effective against both adult and larval stages of these parasites.

How does mebendazole work in the body?

Bc very little of the drug is absorbed systemically, high concentrations of it are retained in the intestine where it kills the pathogens.

How many doses are needed for infections?

For pinworm infections, one dose is usually sufficient. Other infections require 3 consecutive days of therapy.

What are the administration alerts associated with mebendazole administration?

-The drug is most effective when chewed and taken with a fatty meal.

-The drug is teratogenic in lab animals and small amounts are secreted in human milk. It should be taken during pregnancy/lactation only if the potential benefits to the mother justify the potential risks to the fetus/neonate.

What is the onset, peak, and duration of mebendazole?

Onset: 2-4 h

Peak: 1-7 h

Duration: 3-9 h

What are the adverse effects of mebendazole administration?

-abdominal pain

-distention

-diarrhea

(resulting from the worms dying)

When/to whom is it contraindicated to administer mebendazole?

Patients with hypersensitivity to the drug.

What drug-to-drug interactions may occur with mebendazole administration?

Concurrent use with carbamazepine and phenytoin can increase the metabolism of mebendazole.

What herbal/food interaction may occur with mebendazole administration?

High-fat foods may increase the absorption of the drug.

What are the characteristics and treatment of mebendazole overdose?

Characteristics of overdose include upper stomach pain, loss of appetite, dark urine, or jaundice. Treatment does not consist of specific treatment.

What are the therapeutic and pharmacologic classes of Zidovudine?

T: Antiretroviral

P: Nucleoside reverse transcriptase inhibitor (NRTI)

What is the mechanism of action of zidovudine?

It resembles thymidine, one of the four nucleoside building blocks of DNA. As the reverse transcriptase enzyme begins to synthesize viral DNA, it mistakenly uses zidovudine as one of the nucleosides, this creating a defective DNS strand.

Why is zidovudine not included as a first-line drug?

Due to the high potential for resistance.

What is the most frequent indication for zidovudine?

To prevent the transmission of HIV from mother to fetus or neonate.

What are the administration alerts for zidovudine administration?

-Administer on an empty stomach with a full glass of water (no fruit juice).

-Human data hasn't shown evidence of pregnancy-related adverse events above baseline levels. Breastfeeding is not recommended due to the possibility of transmitting HIV to the nursing infant.

What is the onset, peak, and duration of zidovudine?

Onset: 1-2 h

Peak: 1-2 h

Duration: Unknown

What are the adverse effects of zidovudine?

-fatigue

-generalized weakness

-anorexia

-nausea

-diarrhea

What is the black box warning for zidovudine?

Rare cases of fatal lactic acidosis with hepatomegaly and steatosis have been reported with zidovudine use. Bone marrow suppression may result in neutropenia or severe anemia. Myopathy (muscle aches) may occur with long-term use.

When/to whom is zidovudine administration contraindicated?

-Patients with a hypersensitivity to the drug

When/with whom should zidovudine be administered with caution?

-In patients with preexisting anemia or neutropenia.

-Blood counts and other lab blood tests should be monitored frequently during therapy to prevent hematologic toxicity.

-Pt.'s with significant CKD or hepatic impairment require a reduction in dosage because zidovudine may accumulate to toxic levels.

What drug-to-drug interactions may occur with zidovudine administration

-Concurrent administration with other drugs that depress bone marrow function (e.g. ganciclovir, interferon alpha, dapsone, flucytosine, or vincristine) should be avoided due to cumulative immunosuppression.

-Concurrent use with the following drugs may increase the risk of zidovudine toxicity (clozapine, amphotericin B, doxorubicin, fluconazole, methadone, and valproic acid).

-Concurrent use with other antiretroviral agents may cause lactic acidosis and severe hepatomegaly with steatosis.

What herbal/food interactions may occur with zidovudine administration?

Concurrent use with St. John's wort may decrease the drugs antiretroviral activity.

What are the characteristics and treatment of zidovudine overdose?

Characteristics of overdose include tiredness, headache, and vomiting. Treatment includes no specific treatment.

What are the therapeutic and pharmacologic classes of Efavirenz?

T: Antiretroviral

P: Nonnucleoside reverse transcriptase inhibitor (NNRTI)

What is the mechanism of action of efavirenz?

It inhibits reverse transcriptase.

What is efavirenz used to treat?

Used in combination with other antiretrovirals in the treatment of HIV infection.

What undesirable result may occur with efavirenz administration?

-Resistance to NNRTIs can develop rapidly, cross resistance among drugs in this class can occur.

-High-fat meals increase the absorption by as much as 50%-> toxicity

What are the advantages of efavirenz administration?

Once-daily dosing and penetration into CSF.

What is atripla?

A fixed-dose combination of three antiretroviral drugs (efavirenz, emtricitabine, and tenofovir).

What are the administration alerts for efavirenz administration?

-Administer at bedtime to limit adverse CNS effects.

-May cause neural defects in the fetus if taken during pregnancy. Pt.'s of childbearing potential should be advised to use birth control during therapy and for 12 weeks after the drug is discontinued.

What is the onset, peak, and duration of efavirenz administration?

Onset: Rapid

Peak: 3-5 h

Duration: 24 h

What are the adverse effects of efavirenz administration?

(CNS adverse effects observed in at least 50% of patients when first initiating therapy.)

-sleep disorders

-nightmares

-dizziness

-reduced ability to concentrate

-delusions

(^usually diminish after 3-4 weeks of therapy)

-rash (mon. for blistering & desquamation)

When/to whom is efavirenz administration contraindicated?

-Pt.'s who are pregnant b/c the drug is a known teratogen in lab animals, causing neural tube defects.

-Pt.'s in their childbearing years should be advised to use birth control to avoid pregnancy.

What drug-to-drug interactions may occur with efavirenz administration?

-Concurrent use with antiepileptic meds metabolized by the liver (carbamazepine and phenobarbital) require periodic monitoring of plasma levels b/c efavirenz may increase the incidence of seizures.

-Concurrent use with statins, methadone, sertraline, and calcium channel blockers may result in decreased serum levels of the before mentioned drugs.

-Concurrent use with psychotropic drugs or alcohol consumption may worsen CNS adverse effects.

What herbal/food interactions may occur with efavirenz administration?

-St. John's wort may cause a decrease in antiretroviral activity.