Drug interaction

The nurse cares for a patient with a urinary tract infection (UTI). The patient has an allergy to penicillins. Which of the following medications is contraindicated for this patient's illness?

Pharmaceutical incompatibility is a physicochemical interaction that occurs when drugs are mixed in I.V infusions causing precipitation or inactivation of active principles

Pharmacokinetic interactions These interactions are those in which ADME properties of the object drug is altered by the precipitant

Chronic use of alcohol beverages may increases the rate of metabolism of drugs such as warfarin and phenytoin, probably by increasing the activity of hepatic enzymes.

Weak acids need to be absorbed at a high pH. Raising the pH with antacid medication considerably hinders absorption

Antacids, histamine H2 antagonists and omeprazole can significantly decrease the bioavailability of ketoconazole and itraconazole, which require gastric acidity for optimal absorption

The alkalinising effects of antacids on the gastro-intestinal tract are transient and the potential for interaction may be minimised by leaving an interval of 2-3 h between the antacid and the potentially interacting drug.

Metoclopramide decreases gastric emptying and decreases the absorption rate of paracetamol

Opioids such as diamorphine and pethidine strongly inhibit gastric emptying and greatly reduce the absorption rate of paracetamol, without affecting the extent of absorption

Digoxin is a substrate of P-glycoprotein and drugs that inhibit P- glycoprotein, such as verapamil may increase digoxin bioavailability with the potential for digoxin toxicity

Orlistat increases the absorption of lamotrigine

Neomycin increases the absorption of digoxin

If a patient taking phenytoin is given a drug which displaces phenytoin from its binding sites, the total (i.e. Free plus bound) plasma phenytoin concentration will fall even though the free (active) concentration remains the same

Phase I metabolism generally involves the cytochrome P450 (CYP450) mixed function oxidase system

If two medications make it pass the hepatic enzymes, there is potential for interaction at the site of action, or at sites of major side effects

Warfarin with aspirin (Impact of aspirin and chlorthalidone on the pharmacodynamics of oral anticoagulants in man)

Azithromycin is aggressively metabolized by cyp3A4

Clarithromycin is one of the most potent utilizers of Cyp3A4 and entertains vast potential for competitive inhibition with many other medications

Fluconazole turns out to be one of the more benign medications whereas ketoconazole is a very potent inhibitor of cyp3A4

Calcium channel blockers like beta blockers vary in their ability to cause heart block

Grouping medications allows one to extrapolate known data to a certain extent across a drug groups

Hearing patient's complaints can help alert the physician to identifying previously unreported reactions

If erythromycin or clarithromycin (an inhibitor of CYP3A4) is taken by a patient being given carbamazepine (which is extensively metabolised by CYP3A4), this may lead to toxicity due to higher concentrations of carbamazepine

Ketoconazole, Erythromycin, and Clarithromycin are enzyme inhibitors

Ceftriaxone with calcium containing solution form ppt, is an example of

Increased anticoagulant activity of coumarines can be pricipated by concurrent administration of

NSAIDs can increase lithium toxisity throgh.........

Increased plasma levels of penicillin with probenicid administration, is due to

Are those in which the activity of the object drug at its site of action is altered by the precipitant Pharmaceutical interactions

Salicylates decrease the ability of the platelets to aggregate thus impairing the homeostasis if............... Induced bleeding occurs

Acute use of alcohol by ...............individuals may cause an inhibition of hepatic enzymes.

Divalent cations such as calcium or iron can bind to certain medications and prevent their

All of the following are enzyme inducers: Barbiturate, Rifampin, Phenytoin

Enzyme inhibitors: decrease metabolism of concomitant drug therefor increase drug excretion and increase drug effect

Clopidogrel is metabolized via CYP2C19 to an active metabolite which is responsible for its anti-platelet effect

Proton pump inhibitors such as lansoprazole are inhibitors of CYP2C19 and may lead to reduced effectiveness of clopidogrel when used in combination

40% or more of the administered digoxin dose is metabolized by the intestinal flora

Antibiotics kill a large number of the normal flora of the intestine so it increases digoxin toxicity

All of the following are enzyme inducers except........

All of the following are enzyme inhibitors except.........

Phase 2 metabolism include all of the following except..........

Milk and other dairy products that contain calcium may decrease the absorption of tetracycline and flouroquinolone derivatives

Acetylcholine and noradrenaline

Sedatives and hypnotics

Alcohol and aspirin

The nurse assesses patient medications at a primary care clinic. Which of the following patients with osteoporosis should not be prescribed alendronate?

Which of the following antidepressant agents inhibits hepatic microsomal enzymes to cause clinically significant drug-drug interactions?