20. Cross-Cutting PTCE Medication Rules

What should you do when you identify possible therapeutic duplication?

Stop and investigate

What is an example of two NSAIDs being duplicated?

Ibuprofen + naproxen or meloxicam + diclofenac

Why is duplication of two NSAIDs concerning?

Higher GI bleed and renal toxicity risk and usually unnecessary duplication

What is an example of hidden acetaminophen duplication?

Tylenol + Percocet, Norco, or Tylenol #3

Why is hidden acetaminophen duplication dangerous?

Accidental APAP overdose

What is an example of two drugs from the same blood pressure class?

Lisinopril + enalapril or losartan + valsartan

What should you do if two drugs from the same blood pressure class are prescribed?

Verify intent because it is usually duplication

What is an example of ACE inhibitor + ARB duplication?

Lisinopril + losartan

Why is combining an ACE inhibitor and ARB concerning?

More hyperkalemia and renal risk and it is not routine

What is an example of two beta blockers being duplicated?

Metoprolol + propranolol

What can duplicate beta blockers cause?

Bradycardia and hypotension

What is an example of two PPIs being duplicated?

Omeprazole + pantoprazole

Why is using two PPIs concerning?

It is usually unnecessary duplication

What is an example of two statins being duplicated?

Atorvastatin + simvastatin

What can duplicate statin therapy cause?

Myopathy and toxicity

What is an example of duplicate anticoagulation?

Warfarin + apixaban without a transition plan

What is the major risk of duplicate anticoagulation?

Major bleeding

Can duplicate anticoagulation ever be intentional?

Yes, only in specific transitions

What is an example of multiple sedatives being combined?

Opioid + benzodiazepine + Z-drug

What can multiple sedatives cause?

Respiratory depression and falls

What is an example of multiple serotonergic agents?

SSRI + SNRI + tramadol, dextromethorphan, or linezolid

What is the risk of multiple serotonergic agents?

Serotonin syndrome

What is an example of duplicate antihistamines?

Diphenhydramine + hydroxyzine

What can duplicate antihistamines cause?

Sedation and anticholinergic burden

What is an example of duplicate active ingredients in combination products?

Biktarvy plus separate tenofovir/emtricitabine or a combination inhaler plus the same component

Why are duplicate active ingredients in combination products dangerous?

Accidental overdose or duplicate therapy

What is the danger of combining nitrates with PDE-5 inhibitors?

Severe hypotension

What are examples of nitrates + PDE-5 inhibitors?

Nitroglycerin or isosorbide + sildenafil, tadalafil, or vardenafil

What is the danger of combining opioids with benzodiazepines or other CNS depressants?

Respiratory depression and coma

What is an example of an opioid + benzodiazepine interaction?

Oxycodone + alprazolam

What is the danger of combining an ACE inhibitor or ARB with potassium?

Hyperkalemia

What is an example of an ACE inhibitor or ARB + potassium interaction?

Lisinopril or losartan + KCl or spironolactone

What drugs can increase lithium toxicity risk?

Thiazides, ACE inhibitors, ARBs, and NSAIDs

What is an example of a lithium interaction?

Lithium + HCTZ or ibuprofen

What can warfarin interactions cause?

INR and bleeding changes

What are examples of drugs that can interact with warfarin?

TMP/SMX, amiodarone, and many antibiotics

What happens when a carbapenem is combined with valproate?

Valproate levels drop and seizures can occur

What is an example of a carbapenem + valproate interaction?

Meropenem + valproic acid

What can happen when linezolid is combined with serotonergic drugs?

Serotonin syndrome

What is an example of linezolid + serotonergic drug interaction?

Linezolid + sertraline

What is the risk of MAOI-type drugs with dextromethorphan or tramadol?

Serotonin syndrome or hypertensive reactions depending on the drug

What happens when minerals are combined with tetracyclines or fluoroquinolones?

Reduced antibiotic absorption

What is an example of a mineral + antibiotic interaction?

Iron or calcium + doxycycline or ciprofloxacin

What happens when minerals are combined with levothyroxine?

Reduced thyroid hormone absorption

What is an example of a mineral + levothyroxine interaction?

Calcium or iron + levothyroxine

What is the risk of combining a statin with a strong CYP inhibitor or gemfibrozil?

Myopathy and rhabdomyolysis

What is an example of a statin + strong CYP inhibitor interaction?

Simvastatin + clarithromycin

What is an example of a statin + fibrate interaction?

Statin + gemfibrozil

What is the danger of combining sacubitril/valsartan with an ACE inhibitor?

Angioedema

What is an example of sacubitril/valsartan + ACE inhibitor interaction?

Entresto + lisinopril

How long of an ACE inhibitor washout is required with sacubitril/valsartan?

36 hours

What can happen when an estrogen contraceptive is combined with an enzyme inducer?

Reduced contraceptive effectiveness

What is an example of an estrogen contraceptive + enzyme inducer interaction?

Carbamazepine + combined oral contraceptive

What can St. John's Wort do to other medicines?

Cause enzyme induction and/or serotonin toxicity

What are examples of drugs affected by St. John's Wort?

Oral contraceptives, tacrolimus/cyclosporine, and antidepressants

What is the signature test point for opioids?

Respiratory depression, constipation, and sedation

What is the signature test point for NSAIDs?

GI bleed and kidney injury

What is the signature test point for ACE inhibitors?

Cough, hyperkalemia, and angioedema

What is the signature test point for ARBs?

Hyperkalemia with less cough

What is the signature test point for beta blockers?

Bradycardia and masking hypoglycemia

What is the signature test point for DHP calcium channel blockers?

Peripheral edema

What is the signature test point for loop and thiazide diuretics?

Low potassium/sodium and dehydration

What is the signature test point for spironolactone and triamterene?

High potassium

What is the signature test point for statins?

Muscle pain and rhabdomyolysis

What is the signature test point for SSRIs and SNRIs?

Serotonin syndrome and sexual dysfunction

What is the signature test point for antipsychotics?

EPS/NMS and metabolic effects

What is the signature test point for benzodiazepines and Z-drugs?

Sedation, falls, and respiratory depression with opioids

What is the signature test point for stimulants?

Insomnia, appetite loss, and increased blood pressure/heart rate

What is the signature test point for sulfonylureas and insulin?

Hypoglycemia

What is the signature test point for SGLT2 inhibitors?

Genital infection, dehydration, and euglycemic DKA

What is the signature test point for GLP-1/GIP drugs?

Nausea and vomiting

What is the signature test point for PPIs?

Long-term magnesium, C. difficile, and fracture concerns

What is the signature test point for fluoroquinolones?

Tendon injury, neuropathy, and mineral chelation

What is the signature test point for aminoglycosides?

Kidney and ear toxicity

What is the signature test point for vancomycin?

Nephrotoxicity and infusion reaction

What is the signature test point for clindamycin?

C. difficile

What is the signature test point for bisphosphonates?

Esophagitis with oral products and jaw osteonecrosis

What is the signature test point for calcineurin inhibitors?

Nephrotoxicity and interactions

What is the signature test point for inhaled corticosteroids?

Oral thrush and rinse mouth

What are examples of transdermal patches?

Duragesic fentanyl, Lidoderm lidocaine, rivastigmine, Xulane, and Oxytrol

What are important PTCE traps with transdermal patches?

Remove old patch, rotate sites, heat matters for fentanyl, and do not cut unless labeling permits

What are examples of inhalers?

Albuterol, Spiriva, Symbicort, Advair, Flovent, and Pulmicort

What is the PTCE trap with inhalers?

Device technique differs and the mouth should be rinsed after inhaled steroids

What are examples of nasal products?

Narcan, Flonase, azelastine, and Afrin

What is the PTCE trap with nasal products?

Route matters and Afrin should be limited to about 3 days to prevent rebound congestion

What are examples of ophthalmic drops?

Timolol, latanoprost, brimonidine, and dorzolamide

What are PTCE traps with ophthalmic drops?

Avoid touching the dropper tip, separate multiple eye drops, and remember systemic absorption can still occur

What are examples of subcutaneous injections?

Insulin, GLP-1/GIP agents, PCSK9 inhibitors, CGRP monoclonal antibodies, and denosumab

What are PTCE traps with subcutaneous injections?

Refrigeration is common before use, do not freeze, and follow device-specific priming/disposal

What are examples of IV-only or hospital-heavy drugs?

Propofol, vasopressors, many chemotherapy drugs, piperacillin/tazobactam, cefepime, and meropenem

What are PTCE traps with IV-only or hospital-heavy drugs?

Concentration, compatibility, infusion rate, and line selection matter

What are examples of extended-release dosage forms?

OxyContin, MS Contin, Effexor XR, Concerta, Toprol-XL, and Detrol LA

What is the PTCE trap with extended-release dosage forms?

Do not crush or chew unless the exact product labeling allows manipulation

What is important about sublingual nitroglycerin?

Fast onset and protect tablets from moisture/light in the original container

What are examples of implant and vaginal ring contraception?

Nexplanon and NuvaRing

What is the PTCE trap with implant and vaginal ring contraception?

They are long-acting/non-oral routes and should not be confused with oral contraception

What is GoLYTELY?

A large-volume reconstituted bowel prep solution

What is the PTCE trap with GoLYTELY?

Follow mixing and product storage directions

What is the standard refrigerated storage range?

2-8 C or 36-46 F

What products commonly use refrigerated storage?

Unopened insulin and many biologic injectables