Chapter 3.3: Therapeutic Duration; Identify Redundant Therapies

what is redundant therapy?

• patient is prescribed multiple medications for exact same indication or from the same therapeutic class without specific medical necessity

  • dangerous because taking 2 drugs that do the same thing doesn’t increase the cure but increases the risk of toxicity, overdose, and side effects

what drugs contain APAP?

• norco/vicodin (hydrocodone + APAP)

• percocet/endocet (oxycodone + APAP)

• tylenol #3 (Codeine + APAP)

• excedrin (OTC migraine medicine containing APAP, aspirin, and caffeine)

how do people overdose on APAP?

• APAP is a hidden ingredient in many Rx narcotics

• patients may unknowingly take OTC tylenol for headache while simultaneously taking an Rx pain reliever for an injury, without knowing that both pills contain same drug

what happens when you overdose on APAP? what is the max dose for APAP?

• liver damage because liver has a limited capacity to process APAP, exceeding the safety limit → hepatotoxicity (liver damage) → lethal

what is the issue with common “class” duplicates

• patient takes 2 different drugs that belong to the same pharmaceutical family

• because they work on the same body system in the same way, the effects, and side effects are compounded

what happens when a patient takes NSAID + NSAID

• scenario: pt takes ibuprofen (Advil, Motrin) daily for knee pain but visits a doctor for a shoulder injury and receives an rx for Naproxen (Aleve, Naprosyn) or Meloxicam (Mobic)

• taking 2 NSAIDS simultaneous aggressively attacks protective lining of stomach

  • increases GI bleeding, stomach ulcers, and acute kidney failure

• General rule: Pick one NSAID and stick to it

what happens when a patient takes opioid + opioid?

• scenario: if patient takes oxycodone and receives a new rx for morphine/hydrocodone, the risk is severe respiratory depression

• in palliative care/chronic pain management, Dr. sometimes intentionally prescribe “long-acting” opioids like OxyContin for around-the-clock relief and “short-acting” opioid like Oxycodone IR for break thru pain

  • For PTCE, never assume this is intentional

• Opioid + opioid alert: require pharmacist to verify and make sure patient is not overdosing or doc shopping

what happens when a patient takes anticoagulant + anticoagulant?

• blood thinners are high alert because errors → catastrophic effect

• occurs when a new patient is prescribed 2 oral anticoagulants like Warfarin (coumadin), Apixaban (eliquis), Rivaroxaban (xarelto)

• taking 2 blood thinners removes the ability to stop bleeding entirely → spontaneous internal hemorrhage, stroke, or death

• bridging: injectable enoxaparin is temporarily used with warfarin; an execption

what happens when a patient takes ACE and ARB inhibitors?

• K+ spikes

• works on the same exact hormonal pathway (Renin-Angiotensin system) to lower BP → too similar, rarely used together

  • ex: lisinopril + losartan potassium places stress on kidneys → hyperkalemia (very high levels of K+) → cardiac arrest

• if pt is taking ARB and prescribed an ACE, flag it as duplicate

what happens when a patient takes Statin + Statin?

• the muscle risk

• if pt is prescribed atorvastatin (Lipitor) while already taking simvastatin (Zocor) → liver is overwhelmed

• 2 statins increase risk of myopathy (severe muscle pain) and a serious condition called Rhabdomyolysis →muscle tissue breaks down and clogs kidneys

what is the exception about combination therapy?

• treating complex diseases like hypertension often required to attack problem from multiple angles

• it’s appropriate for patients to take BP med from different classes simultaneously

  • ex: pt is taking lisinopril (ACE) and amlodipine (CCB) is NOT duplication therapy

• safe combo: diff suffixes = diff mechanisms

• dangerous combo: same suffixes = redundant toxicity