A patient has been stable on warfarin, with an international normalized ratio (INR) in range. Which antibiotic, if added, is most likely to push the INR up?
Sulfamethoxazole-trimethoprim Sulfamethoxazole inhibits CYP2C9, the enzyme that clears S-warfarin, the more potent part of warfarin. Warfarin levels rise, the INR goes up and the bleeding risk grows, so the INR needs closer checks or a different antibiotic.
A patient taking lisinopril for heart failure is starting spironolactone. Which lab value needs the closest watch?
Serum potassium Both drugs raise potassium: lisinopril by lowering aldosterone, and spironolactone by blocking aldosterone’s effect in the kidney. Together they raise the risk of hyperkalemia, so potassium and kidney function are checked shortly after the start and regularly after that.
Under its US labeling, below which estimated glomerular filtration rate (eGFR) is metformin contraindicated?
30 mL/min/1.73 m² Metformin’s US labeling says it’s contraindicated when the eGFR is below 30 mL/min/1.73 m², because poor kidney clearance raises the risk of lactic acidosis. Starting it isn’t recommended when the eGFR is between 30 and 45.
An order reads vancomycin 1 g in 250 mL, to run over 2 hours. What rate do you set on the pump?
125 mL an hour An infusion rate is the volume divided by the time: 250 mL over 2 hours is 125 mL an hour. The amount of drug in the bag doesn’t change the rate when the whole bag runs over a set time.
Under federal law, which Drug Enforcement Administration (DEA) form does a pharmacy use to order Schedule II controlled substances on paper from a supplier?
DEA Form 222 DEA Form 222 is the order form for Schedule I and II controlled substances, and the Controlled Substance Ordering System (CSOS) is its electronic alternative. Drugs in Schedules III to V don’t need it.
A patient taking a statin is prescribed clarithromycin. With which statin does the labeling make this combination contraindicated?
Simvastatin Simvastatin is broken down mainly by CYP3A4, and clarithromycin strongly inhibits that enzyme. Simvastatin levels can rise far enough to risk myopathy and rhabdomyolysis, so its labeling lists strong CYP3A4 inhibitors such as clarithromycin as contraindicated.
A patient takes levothyroxine each morning and has started calcium carbonate. What is the best advice?
Separate the two by at least 4 hours Calcium carbonate binds levothyroxine in the gut and lowers how much is absorbed. Levothyroxine’s labeling advises taking it at least 4 hours apart from calcium carbonate.
Under federal law, how many times can a prescription for a Schedule III controlled substance be refilled?
Up to 5 times within 6 months Federal law lets a Schedule III or IV prescription be refilled up to 5 times, and not after 6 months from the date it was written. A state can set a stricter rule, and then the stricter rule applies.
Which agent is the specific reversal agent for dabigatran?
Idarucizumab Dabigatran is a direct thrombin inhibitor. Idarucizumab, a monoclonal antibody fragment, binds dabigatran and neutralizes its effect, for emergency surgery or life-threatening bleeding.
Which of these blood pressure medicines should be avoided in pregnancy?
Lisinopril Lisinopril is an angiotensin-converting enzyme (ACE) inhibitor, and drugs that act on the renin-angiotensin system can injure and kill the developing fetus. Its US labeling has a boxed warning to stop it when pregnancy is detected.
A 34-year-old with asthma, who uses an albuterol inhaler, is prescribed propranolol to prevent migraine. What is the main concern?
Propranolol can trigger bronchospasm Propranolol is a nonselective beta blocker, so it blocks beta-2 receptors in the airways as well as beta-1 receptors in the heart. In asthma that can trigger bronchospasm and blunt the response to albuterol, so it’s generally avoided.
Under the Poison Prevention Packaging Act, which of these can a pharmacy dispense in a non-child-resistant container without anyone asking for one?
Sublingual nitroglycerin tablets The Poison Prevention Packaging Act regulations exempt sublingual nitroglycerin from child-resistant packaging, so a patient can open it quickly during chest pain. Other oral prescription drugs go in child-resistant packaging unless they’re exempt or the patient or prescriber asks otherwise.
A patient taking sertraline needs an antibiotic. Which choice raises the risk of serotonin syndrome?
Linezolid Linezolid is a weak, reversible monoamine oxidase inhibitor (MAOI). With a selective serotonin reuptake inhibitor (SSRI) such as sertraline, it can cause serotonin syndrome, so its labeling warns against the combination unless the patient is closely watched.
Ciprofloxacin tablets should be taken at least 2 hours before or 6 hours after which product?
Magnesium-aluminum antacids Magnesium and aluminum bind ciprofloxacin in the gut and can sharply cut how much is absorbed. Ciprofloxacin’s labeling says to take it at least 2 hours before or 6 hours after these antacids.
Under federal law, what is the most pseudoephedrine base a retailer may sell to one customer in a day?
3.6 g The Combat Methamphetamine Epidemic Act limits retail sales to 3.6 g of pseudoephedrine base per customer a day, and 9 g in 30 days. A state can set lower limits.
Which vaccine is a live attenuated vaccine?
Measles, mumps and rubella (MMR) The MMR vaccine contains live, weakened measles, mumps and rubella viruses. That’s why it isn’t given during pregnancy or to people with severely weakened immune systems.
How many milligrams of sodium chloride are in each milliliter of 0.9% sodium chloride injection?
9 mg A percentage strength for a solution means grams per 100 mL, so 0.9% is 0.9 g in 100 mL. That’s 900 mg in 100 mL, or 9 mg in each milliliter.
A drug with a half-life of 6 hours is given on a regular schedule. About how long does it take to reach steady state?
24 to 30 hours On regular dosing, a drug reaches steady state after about 4 to 5 half-lives. With a 6-hour half-life, that’s about 24 to 30 hours.
Which Food and Drug Administration (FDA) publication lists therapeutic equivalence ratings, such as “AB”, for generic drugs?
The Orange Book The Orange Book, formally Approved Drug Products with Therapeutic Equivalence Evaluations, lists FDA-approved drugs and their therapeutic equivalence codes. An “AB” rating means the FDA considers the product therapeutically equivalent to its reference drug.
Which insulin is a long-acting basal insulin?
Insulin glargine Insulin glargine is a long-acting insulin that’s absorbed slowly and gives a fairly steady level for about a day. That’s why it’s used as basal, background insulin.
United States · Licensing exam