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7/23/2018
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Drug Adjustments in Older Adults
Marilyn N. Bulloch PharmD, BCPS, FCCMAssociate Clinical Professor
Harrison School of Pharmacy
Auburn University
Disclosures
• Alabama Medicaid Drug Utilization Board
• Pharmacy Times Contributor
Objectives
• Discuss age-related physiologic changes and their subsequent impact on medication use in older adults
• Describe methods for determining need for dose-adjustments based on physiologic changes in older patients
• Recognize dosage forms that cannot be altered and identify potential alternative drug delivery methods
• Explain scales and formulas that have been developed to guide medication dose-adjustments
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Drug Related Complications
Medication Issue
Polypharmacy
Socioeconomic
Physiologic changesComorbidities
Cognition
Suboptimal Prescribing
Overuse Underuse
Inappropriate use Suboptimal use
Suboptimal Prescribing
Lack of Data In Older Adults
• Few medications have specific dose recommendations for geriatrics
• Only 32% of phase II and III study patients are > 65 years old– Up to 35% published studies specifically excluded geriatrics
• Reasons for exclusions– Comorbidities, ageism, economics, communication barriers
• FDA guidance document recommends, but does not require inclusion of geriatrics
Shenoy et al. Perspect Clin Res.2015;6:184-9Watts G. BMJ 2012;344:e3445Herrera et al. Am J Pub Health. 2010;100:s105-112
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Industry Guidance on Organ Impairment Studies
http://www.appliedclinicaltrialsonline.com/early-phase-clinical-trials-patients-hepatic-or-renal-impairment
Age-Related Physiologic Changes
Turnheim. Drugs and Aging.1998;13:357-79Image credit: https://nursekey.com/8-safe-medication-use/
Receptor down regulationChanges in receptor sensitivity
Altered homeostasis mechanisms
“Synergistic” drug-body effects
Roberts et al. Clin Ger Med.1988;4:127-145
Age-Related Physiologic Changes
Turnheim. Drugs and Aging.1998;13:357-79Image credit: https://nursekey.com/8-safe-medication-use/
Receptor down regulationChanges in receptor sensitivity
Altered homeostasis mechanisms
“Synergistic” drug-body effects
Roberts et al. Clin Ger Med.1988;4:127-145
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Drugs Affected By Absorption Changes
Thomas et al. Drugs & Aging.1998;13:199-209Myers et al. Clin Pharmacokin.1989;17:385-95
Others• Pravastatin – H+-coupled monocarboxylic acid-specific transporter• Folate – pH dependent carrier-mediated transporter• Penicillin - ↑ bioavailability due to higher pH; ↓ absorption of IM agent
Obesity
Barras et al. Australian Prescriber.2017:40:189-193
Obesity
Others• Erythromycin – IBW
• Rifampin – IBW
• Theophylline – IBW
• Carvedilol – max 100 mg dose in ≥ 100 kg
Barras et al. Australian Prescriber.2017:40:189-193
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Protein Binding
Shargel L, Yu AC. Applied Biopharmaceutics & Pharmacokinetics, 7e; 2016 Available at: https://accesspharmacy.mhmedical.com/content.aspx?sectionid=100671709&bookid=1592&Resultclick=2 Accessed: April 02, 2018
Highly Protein Bound Medications
• Indomethacin
• Sulindac
• Ibuprofen
• Naproxen
• Piroxicam
• Phenytoin
• Valproic acid
• Glipizide
• Glyburide
• Digoxin
• Diphenhydramine
• Doxycycline
• Clindamycin
• Dicloxacillin
• Cisplatin
• Vincristine
• Acetazolamide
• Furosemide
• Bumetanide
• Chlorthalidone
• Metolozone
Creatinine Clearance
Image credit: https://www.hepatitisc.uw.edu/go/special-populations-situations/treament-renal-impairment/core-concept/allImage credit: http://www.patientcareonline.com/depression/early-renal-disease
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Adjusting Dose: Decreased Kidney Function
• 2nd generation antihistamines
• H1RAs
• Amantadine
• Gout medications
• Gabapentin
• Pregabalin
• Most antimicrobials
• Fesoterodine
• Hydrophillic beta-blockers- atenolol, bisoprolol, nadolol
• Opioids: morphine, codeine
• ACE-inhibitors
• Statins – rosuvastatin, simvastatin, lovastatin
American Geriatrics Society 2015 Beers Criteria Update Expert Panel. J Am Geriatr Soc. 2015;63:2227-47
Hepatic
• 20% of all medications in patients with chronic hepatic dysfunction are dosed incorrectly.– 30% experience ADRs → 80% ADRs are preventable
• Liver Flashback– Enzymes that metabolize drugs located in most body
tissue BUT are in highest levels and most diverse in liver
Weersink. BMJ Open. 2016;6:e012991
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Liver and Drug Metabolism
Trevor AJ, Katzung BG, Kruidering-Hall M. Katzung & Trevor's Pharmacology: Examination & Board Review, 11e; 2015 Available at: https://accesspharmacy.mhmedical.com/ViewLarge.aspx?figid=95701060 Accessed: April 11, 2018
Brunton LL, Hilal-Dandan R, Knollmann BC. Goodman & Gilman's: The Pharmacological Basis of Therapeutics, 13e; 2017 Available at: https://accesspharmacy.mhmedical.com/ViewLarge.aspx?figid=172473542 Accessed: April 11, 2018
Hepatic
• Liver – primary organ for drug metabolism occurring in hepatocytes– Phase I – oxidation, reduction, hdyrolosis
– Phase II – glucuronidation, sulfation, acetylation, methylation
• First Pass Metabolism – pre-systemic metabolism after oral intake but before entry into systemic circulation. – May be impacted by ↓ intrinsic clearance → increase in absolute oral
bioavailability• Increased blood concentrations – morphine, meperidine, verapamil, metoprolol,
labetalol, carvedilol, midazolam
• Prodrugs – may see decreased conversion to active form– E.g. clopidogrel, enalapril
Weersink. BMJ Open. 2016;6:e012991Pena et al. Exp Rev Clin Pharmacol.2016;9:441-458
Child-Pugh Classification
Pena et al. Exp Rev Clin Pharmacol.2016;9:441-458
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Hepatic Adjustments: EBM Recommendations
• Unsafe in all hepatic dysfunction – avoid– NSAIDs
– Nebivolol
– Isradipine
– Oral Nicardipine
– Triamterene
– Cimetidine
– Lansoprazole
– Pantoprazole
– Budesonide
– Atorvastatin
– DuloxetineWeersink et al. Drug Saf.2018:httos://doi.org/10.1007/s40264-0635-xPena et al. Exp Rev Clin Pharmacol.2016;9:441-458
Hepatic Adjustments: EBM Recommendations
Unsafe
Child-Pugh C Only• ACE inhibitors
• Domperidone
• Clopidogrel
• Rabeprazole
• Omeprazole
• Verapamil
• Felodipine
• Metoprolol
• Carvedilol
• Diazepam (oral)
• COX2 inhibitors
• Tapentadol
• Morphine
• Hydromorphone
• Tramadol
• Fentanyl
Child-Pugh B and C
• Codeine
• Ezetimibe
• Lomitapide
• Oxycodone
Weersink et al. Drug Saf.2018:httos://doi.org/10.1007/s40264-0635-xPena et al. Exp Rev Clin Pharmacol.2016;9:441-458Image: https://edrugsearch.com/worst-medications-for-liver/
Hepatic Adjustments: EBM Recommendations
Reduce Dose • Simvastatin
• Rosuvastatin
• Pravastatin
• Fluvastatin
• Omeprazole (CP A/B)
• Rabeprazole(CP A/B)
• Verapamil (CP A/B)
• Felodipine (CP A/B)
• Metoprolol (CP A/B)
• Repaglinide
• Most opioids (CP A/B)
• Most antiarrhythmics
• Escitalopram
• Venalfaxine
• Bupropion
• Fluoxetine
• Lamotrigine
Varies by severity– avoid if possible or reduce dose• Prasugrel
• Ticagrelor
• Dipyridamole
• Gemfibrozil
• Sitagliptin
• Canagliflozin
• Alogliptin
• Fentanyl
• Tigecycline
• Qunidine
• Mexiletine
• LithiumWeersink et al. Drug Saf.2018:httos://doi.org/10.1007/s40264-0635-xPena et al. Exp Rev Clin Pharmacol.2016;9:441-458
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Hepatic Adjustments: EBM Recommendations
SAFE!!
• Acetaminophen
• Ciprofloxacin
• Norfloxacin
• Ofloxacin
• Moxifloxacin
• Amoxicillin
• Amoxicillin/clav• Piperacillin/tazobactam
• SMX/TMP
• Azithromycin
• Erythromycin
• Fosfomycin
• Rifaximin
• Acarbose
• Insulin
• Metformin
• Atenolol
• Labetalol (IV)
• Sotalol
• HCTZ
• Amiloride
• Furosemide
• Bumetanide
• Spironolactone
• Eplerenone
• Prednisolone
• Prednisone
• Lactulose
• Cholestyramine
• Colesevalam
• Bisacodyl
• Ranitidine
• Famotidine
• Empagliflozin
• Saxagliptin
• Acebutolol
Weersink et al. Drug Saf.2018:httos://doi.org/10.1007/s40264-0635-xPena et al. Exp Rev Clin Pharmacol.2016;9:441-458
Hepatic Adjustments: EBM Recommendations
SAFE with Dose Adjustment
• Tolbutamide
• Propranolol
• Carvedilol
• Labetalol (oral)
• Amlodipine
• Nifedipine
• Nimodipine
• Metoclopramide
• Aspirin
• Esomeprazole
Weersink et al. Drug Saf.2018:httos://doi.org/10.1007/s40264-0635-xPena et al. Exp Rev Clin Pharmacol.2016;9:441-458
Dose Adjustments
Pena et al. Exp Rev Clin Pharmacol.2016;9:441-458
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Hepatic Adjustments: When EBM Does Not Exist
Verbeeck. Eur J Clin Pharmacol.2008;64:1147-1161
Characteristic Rationale Dose Adjustment
High EH Oral BA significantly ↑Plasma Cl may be ↓
↓ dose
Low EH and > 90% protein binding
Intrinsic clearance ↓↓ protein binding
Adjust even if dose within normal blood concentrations
Low EH and < 90% protein binding
Intrinsic clearance ↓↓ protein binding
Maintain normal total blood concentrations
Partly excreted unchanged in kidneys
Elimination ↓ ↓ dose
Hydrophilic Vd increased with edema,ascites
↑ loading doses
Narrow Therapeutic Index Avoid as much as possible
EH - hepatic extraction ratio
Special PK Considerations
• HCTZ– ↑ plasma concentrations (related to ↑ half-life and ↓CL)
– More electrolyte issues, but less response with doses > 50 mg
• Triamterene– ↑ Cmax (related to ↓CL)
• Diltiazem– ↓ absorption rate (unknown impact on bioavailability)
– ↓ CL and ↑ half-life
– Start with lower doses
• Verapamil– ↓ CL and ↑ half-life
– Start with lower doses
Facts and ComparisonsPiepho et al. Drugs & Aging.1991;1:194-211
Special PK Considerations
• Nifedipine– ↓ absorption rate but ↑ bioavailability
– ↓ Cmax and ↑AUC
– ↑ half-life ↓ CL
• Amlodipine– ↓ CL : start with lower doses
Facts and ComparisonsPiepho et al. Drugs & Aging.1991;1:194-211
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Pharmacogenomics
• Identification of phenotypes for certain genes
• Data required in labeling by FDA
• May help guide need to: Adjust dose, use with caution, or use an alternative agent
• Some identify patients at risk for hypersensitivity reaction
• Phenotypes– Poor Metabolizers
– Intermediate Metabolizers
– Extensive Metabolizers
– Ultra-Rapid Metabolizers
https://www.cms.gov/medicare-coverage-database/details/lcd-details.aspx?LCDId=35332&ver=11&CntrctrSelected=228*2&Cntrctr=228&s=22&DocType=All&LCntrctr=140*2&bc=AggAAAIBAAAA&Finkelstein et al. Pharmacogenomics and Personalized Medicine.2016;9:31-45Image: Mayo Clinic
Pharmacogenomics Testing Availability
• Allopurinol
• Aspirin
• TCAs
• Antipsychotics
• Carisoprodol
• Carbamazepine
• Oxcarbazepine
• Clopidogrel
• Donepezil
• Opioids
• SSRIs
• SNRIs
• Ivacaftor
• PPIs
• NSAIDs
• Brivaracetam
• Glimepiride
• Glipizide
• Fluoroquinolones
• Nitrofurantoin
• Bactrim
• Aminoglycosides
• Ondansetron
• Phenytoin
• Tacrolimus
• Tamoxifen
• Tramadol
• Voriconazole
• Valproic acid
• Warfarin
• Carvedilol
• Clozapine
• Diazepam
• Dolasetron
• Flecanide
• Haloperidol
• Metoprolol
• Propafenone
• Propranolol
• Tamsulosin
• Tiotropium
• Tolterodine
• Digoxin
• Salmeterol
• ACE-Is
• Statins
• Bisphosphonates
• Budesonide
• Furosemidde
• Galantamine
• HCTZ
• Lamotrigine
• Latanoprost
• Metformin
• Metoclopramide
• Spironolactone
• Hydralazine
• Isosorbide dinitrate
https://cpicpgx.org/genes-drugs/
Pharmacogenomics Medicare Coverage
• CYP2C19 – metabolizes 15% of medications
• Covered– Clopidogrel – for patients with ACS undergoing PCI
• Not covered– PPIs
– SSRIs
– Amitriptyline
– Warfarin
– Clopidogrel for other indications (including ACS without PCI)
https://www.cms.gov/medicare-coverage-database/details/lcd-details.aspx?LCDId=35332&ver=11&CntrctrSelected=228*2&Cntrctr=228&s=22&DocType=All&LCntrctr=140*2&bc=AggAAAIBAAAA&
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Pharmacogenomics Medicare Coverage
• CYP2D6 – metabolizes 20-25% of all drugs
• Covered– Amitriptyline and nortriptyline for depression
– Tetrabenazine doses > 50 mg/day
• Not covered– Tamoxifen
– Antidepressants (except above)
– Codeine
– Antipsychotics
– Donepezil
– Galantamine
https://www.cms.gov/medicare-coverage-database/details/lcd-details.aspx?LCDId=35332&ver=11&CntrctrSelected=228*2&Cntrctr=228&s=22&DocType=All&LCntrctr=140*2&bc=AggAAAIBAAAA&
Pharmacogenomics Medicare Coverage
• CYP2C9 – metabolized 10% of medications
• Covered– Warfarin (with strict restrictions)
• Not covered– NSAIDs
– Flovoxamine
https://www.cms.gov/medicare-coverage-database/details/lcd-details.aspx?LCDId=35332&ver=11&CntrctrSelected=228*2&Cntrctr=228&s=22&DocType=All&LCntrctr=140*2&bc=AggAAAIBAAAA&
OTHER DRUG DELIVERY CONSIDERATIONS
When Patients Cannot Swallow Pills
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Dysphagia in LTC
• > 60% of all active pharmaceutical ingredients are developed and intended for oral administration– Rationale: ease of administration, increased product
stability, cheaper to manufacturer
• 40-80% of patients in nursing homes may have difficulty swallowing
• 33-60% non-dysphagic ambulatory patients have some difficulty swallowing oral dosage forms
Logrippo et al. Clin Int Age.2017;12:241-51Schiele et al. Dysphagia.2015;30”571-82Carvajal et al. Farm Hosp.2016;40:514-28Manrique et al J Pharm Pharm Sci 2014;17:207-19
Pill Manipulation
• Tablet crushing or capsule opening
• Dispersion/dissolution of material in water, beverages, gels, or food– May allow better deglutition
– Administered orally or via PEG tube
• Any manipulation of approved product is considered an “off-label use” unless outlined in labeling– Technically – prescribers, nurses, and pharmacists can be legally
liable for ADRs resulting from medication administration and use
• Frequent occurrence in LTC
• Up to 42% of medications crushed in LTC should not be
Logrippo et al. Clin Int Age.2017;12:241-51Carvajal et al. Farm Hosp.2016;40:514-28Manrique et al. J Pharm Pharm Sci.2014;17:207-19
Pill Manipulation: Stroke Study
• German study of stroke patients in acute care ward or rehab
• 42.3% of solid oral dosage forms (154/364) prescribed for 25 patients were crushed
• 1/5 inadequately crushed– 47% could have been put into suspension
– 53% had pharmaceutical equivalents or therapeutically equivalent dosage forms suitable for crushing or suspending
• 1/3 required crushing just before administration due to stability concerns
• 38 drugs with unjustified crushing: Pantoprazole, metoprolol SR, probiotics, others
Schiele et al. Dysphagia.2015;30”571-82
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Avoid Crushing: Narrow Therapeutic Window Drugs
Problems
• Imprecise dose
• ↓stability in solution
• Impacted stability when mixed with food, drinks, or vicious gels
Examples
• Warfarin
• Carbamazepine
• Digoxin
• Lithium
• Theophylline
• Phenytoin
Logrippo et al. Clin Int Age.2017;12:241-51
Avoid Crushing: Modified –Release Dosage Forms
Problems
• Altered amount of API released over time– Dose dumping
• Altered API release site –impact absorption
Examples
• Pantoprazole
• Rabeprazole
• Quetiapine
• Tamsulosin
• Levodopa/carbidopa
• Pentoxifylline
Logrippo et al. Clin Int Age.2017;12:241-51
Avoid Crushing: Prolonged/Slow Release
• Nifedipine
• Aggrenox
• Allegra-D
• Lovastatin
• Lubiprostone
• Dutasteride
• Brivaracetam
• Duloxetine
• Divalproex
• Topiramate
• Rivaroxaban
• Isosorbide
• Guanfacine
• Paliperidone
• Hyoscyamine
• Guaifenesin
• Mirabegron
• Felodipine
• Ranolazine
• Benzonate
• Extended release
ISMP: Oral Dosage Forms That Should Not be Crushed 2016
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Avoid Crushing: Enteric Coated Formulations
Problems
• APIs are often acid-labile – designed to be absorbed in intestines
• Drug inactivated by gastric acid
Examples
• Prolonged-release drugs
• Brivaracetam
• Diltiazem
• Pancrelipase
• Bisacodyl
• Erythromycin
• Tamsulosin
• Exceptions– Microencapsulated
oxycodone
Logrippo et al. Clin Int Age.2017;12:241-51
Avoid Crushing: Enteric Coated GI Irritants
Problems
• Safety– Diarrhea
– Mucosal damage
– Perforation
– Hemorrhage
• Efficacy– Delayed absorption/onset
– Inactivated
Examples
• Ferrous sulfate
• Bisphosphonates
• KCL
• NSAIDs
• Tetracyclines
• Clindamycin
• Valganciclovir
Logrippo et al. Clin Int Age.2017;12:241-51
Alternatives in Dysphagia
• Orally disintegrating tablets
• Transdermal patches
• Pulmonary delivery– Under development – levodopa
• Intranasal– Under development - donepezil
• Compounds
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DRUG INTERACTIONS
American Geriatrics Society 2015 Beers Criteria Update Expert Panel. J Am Geriatr Soc. 2015;63:2227-47
Hines et al. Am J Geriatr Pharmacother. 2011;9:364-377
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Hines et al. Am J Geriatr Pharmacother. 2011;9:364-377
Hines et al. Am J Geriatr Pharmacother. 2011;9:364-377
Hines et al. Am J Geriatr Pharmacother. 2011;9:364-377
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MATH AND SCALES
Anticholinergic Burden Calculator
http://www.anticholinergicscales.es/calculate
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Scales• Anticholinergic Risk Scale (ARS)
– Rudolph JL, Salow MJ, Angelini MC, McGlinchey RE. The anticholinergic risk scale and anticholinergic adverse effects in older persons. Arch Intern Med. 2008; 168(5):508-13.
• Chew’s scale (Chew)
– Chew ML, Mulsant BH, Pollock BG, Lehman ME, Greenspan A, Mahmoud RA, et al. Anticholinergic activity of 107 medications commonly used by older adults. J Am Geriatr Soc. 2008; 56(7):1333-41.
• Anticholinergic Drug Scale (ADS)
– Carnahan RM, Lund BC, Perry PJ, Pollock BG, Culp KR. The Anticholinergic Drug Scale as a measure of drug-related anticholinergic burden: associations with serum anticholinergic activity. J Clin Pharmacol. 2006; 46:1481-6.- Update ADS score 2013
• Anticholinergic Activity Scale (AAS)
– Ehrt U, Broich K, Larsen JP, Ballard C, Aarsland D. Use of drugs with anticholinergic effect and impact on cognition in Parkinson's disease: a cohort study. J Neurol Neurosurg Psychiatry. 2010; 81(2):160-5.
• Anticholinergic Load Scale (ALS)
– Sittironnarit G, Ames D, Bush A, Faux N, Flicker L, Foster J, et al. Effects of anticholinergic drugs on cognitive function in older Australians: results from the AIBL study. Dement Geriatr CognDisord. 2011; 31(3):173-8.
http://www.anticholinergicscales.es/calculate
Scales
• Clinician-Rated Anticholinergic Scale (CrAS) – Han L, Agostini JV, Allore HG, Abrahamowicz M, Primeau F, Élie M. Cumulative anticholinergic exposure is associated with
poor memory and executive function in older men. J Am Geriatr Soc. 2008; 56:2203-10.
• Duran’s scale (Duran) – Durán CE, Azermai M, Vander Stichele RH. Systematic review of anticholinergic risk scales in older adults. Eur J Clin
Pharmacol. 2013; 69(7):1485-96.
• Anticholinergic Burden Classification (ABC) – Ancelin ML, Artero S, Portet F, Dupuy AM, Touchon J, Ritchie K. Non-degenerative mild cognitive impairment in elderly
people and use of anticholinergic drugs: longitudinal cohort study. BMJ. 2006; 332:455-9.
• Drug Burden Index (DBI) – Hilmer SN, Mager DE, Simonsick EM, Cao Y, Ling SM, Windham BG, et al. A drug burden index to define the functional
burden of medications in older people. Arch Intern Med. 2007; 167 (8): 781-7.- Dispennette R, Elliott D, Nguyen L, Richmond R. Drug Burden Index score and anticholinergic risk scale as predictors of readmission to the hospital. Consult Pharm. 2014; 29(3):158-68.- Spanish Agency of Medicines and Medical Devices – AEMPS
– A.M. Villalba-Moreno, et al., Systematic review on the use of anticholinergic scales in poly pathological patients, Arch. Gerontol. Geriatr. (2015), http://dx.doi.org/10.1016/j.archger.2015.10.002d
http://www.anticholinergicscales.es/calculate
Ultimate Rules for Drug Dosing
• Start Low and Go Slow
• Trust Nothing
• Look up everything!
• Look up everything often.
• Treat each new symptom as an ADR until proven otherwise.
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QUESTIONS?
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