The pain­ful truth about li­do­caine patches

Cur­rent ex­pen­di­ture on th­ese patches is ¤30m a year yet their ef­fec­tive­ness in the treat­ment of os­teoarthri­tis is not backed up by clin­i­cal ev­i­dence

The Irish Times - Tuesday - Health - - Health Pain Management - Ge­orge Win­ter

Pain is one sen­sa­tion we’ve all shared, yet our ex­pe­ri­ence of it is soli­tary. As Descartes didn’t say, “I hurt there­fore I’m alone”.

Pain was de­fined in 1979 by the In­ter­na­tional As­so­ci­a­tion for the Study of Pain as “an un­pleas­ant sen­sory and emo­tional ex­pe­ri­ence as­so­ci­ated with ac­tual or po­ten­tial tis­sue dam­age, or de­scribed in terms of such dam­age”, and is a com­mon rea­son for see­ing a doc­tor.

Yet when his­to­rian Prof Roy Porter (1946-2002) sought med­i­cal views on pain down the cen­turies, he “con­sulted the pick of the ref­er­ence books, Rod­er­ick McGrew’s En­cy­clopae­dia of Med­i­cal His­tory (1985). No en­try was to be found . . .”

“Pain,” con­cluded Prof Porter in the Lon­don Re­view of Books (Novem­ber 2nd, 1995), “ap­pears to have be­come an em­bar­rass­ment”.

Em­bar­rass­ment or not, pain is preva­lent and presents a sig­nif­i­cant pub­lic health prob­lem in Ire­land. For ex­am­ple, a study from the Cen­tre for Pain Re­search at NUI Gal­way found a 35 per cent preva­lence rate of chronic pain among adults. “The cost of chronic pain per pa­tient was ¤5,665 per year – ex­trap­o­lated to ¤5.34 bil­lion or 2.86 per cent of Gross Do­mes­tic Prod­uct per year.”

Arthri­tis is the sin­gle big­gest cause of dis­abil­ity in Ire­land, af­fect­ing al­most one mil­lion peo­ple and a 2015 re­port in the Euro­pean Jour­nal of Pub­lic Health stated that the over­all preva­lence of os­teoarthri­tis (OA) in Ire­land was 12.9 per cent (women, 17.3 per cent; men, 9.4 per cent).

Ac­cord­ing to the HSE, the med­i­cal treat­ment of OA in­cludes parac­eta­mol; opi­oids such as codeine; non-steroidal anti-in­flam­ma­tory drugs; cap­saicin cream; and in­jec­tions into the af­fected joint(s).

How­ever, one treat­ment not rec­om­mended for OA is the ap­pli­ca­tion of top­i­cal li­do­caine patches (TLPs), with the HSE stat­ing that TLPs are li­censed “ONLY in the treat­ment of neu­ro­pathic pain as­so­ci­ated with post-her­petic neu­ral­gia (PHN) and should be pre­scribed ONLY for this in­di­ca­tion” and that “pa­tients pre­scribed li­do­caine 5 per cent plas­ter for un­li­censed in­di­ca­tions should be re­viewed and treat­ment dis­con­tin­ued”.

No clin­i­cal ev­i­dence

There is no clin­i­cal ev­i­dence sup­port­ing the use of TLPs in the treat­ment of OA – or any other in­di­ca­tion be­sides PHN. Yet only 5 to 10 per cent of pa­tients on TLPs have PHN; the com­mon­est in­di­ca­tion for pre­scrib­ing TLPs in Ire­land is OA; and cur­rent na­tional ex­pen­di­ture on TLPs ex­ceeds ¤30 mil­lion an­nu­ally. Th­ese ob­ser­va­tions are cited by the au­thors of a re­cent ma­jor study, pub­lished in the Ir­ish Jour­nal of Med­i­cal Science.

They note that re­cent changes in na­tional health pol­icy limit the re­im­burse­ment of TLPs on the Drug Pay­ment Scheme to the treat­ment of PHN and in ex­cep­tional cir­cum­stances, but “this leg­is­la­tion af­fects only out­pa­tient pre­scrip­tions, and there is cur­rently no lim­i­ta­tion on in­pa­tient pre­scrib­ing”.

Se­nior au­thor Mr James Sproule of Tal­laght Univer­sity Hos­pi­tal’s Depart­ment of Or­thopaedics helped de­vise the study, which had two aims. First, to de­ter­mine how many pa­tients at Tal­laght Univer­sity Hos­pi­tal re­ceived TLP ther­apy and de­scribe the as­so­ci­ated pre­scrib­ing pat­terns. Sec­ond, “to de­ter­mine whether in­ap­pro­pri­ate pre­scrib­ing prac­tices could be re­duced by ed­u­ca­tion ses­sions de­liv­ered by peers”.

When 304 in­pa­tients were au­dited in Au­gust 2017, 52 (17 per cent) were on TLPs, mainly for mus­cu­loskele­tal pain, and – sig­nif­i­cantly – none had a his­tory of PHN. Fol­low­ing pre­scriber ed­u­ca­tion to in­terns – ju­nior doc­tors – on the proper use of TLPs, a re-au­dit of 300 in­pa­tients in Fe­bru­ary 2018 re­vealed that the num­ber of in­pa­tients on TLPs – most of whom had mus­cu­loskele­tal pain – had fallen to 18 (6 per cent): “The po­ten­tial sav­ings be­tween the study pe­ri­ods are there­fore ¤31,418-¤93,840 in to­tal and ¤23,100-¤69,000 in mus­cu­loskele­tal pa­tients.”

So, should all med­i­cal grades, in­clud­ing con­sul­tants, be ed­u­cated on the ap­pro­pri­ate pre­scrib­ing of TLPs? The study’s cor­re­spond­ing au­thor Dr Rosie McCol­gan said: “Most doc­tors in this coun­try move hos­pi­tal or depart­ment ev­ery six months, so de­liv­er­ing reg­u­lar ed­u­ca­tion on the topic would be a dif­fi­cult task.”

How­ever, she pointed out that al­though no clin­i­cal ev­i­dence sup­ports the use of TLP in os­teoarthri­tis, some pain spe­cial­ists be­lieve they may have a role in the man­age­ment of chronic pain con­di­tions: “If the pre­scrip­tion of TLP was lim­ited to anaes­thetic and pain con­sul­tants only, this should re­sult in a dra­matic re­duc­tion in in­ap­pro­pri­ate hos­pi­tal pre­scrib­ing and th­ese funds could be redi­rected to ev­i­dence-based in­ter­ven­tions for os­teoarthri­tis such as to­tal hip or knee re­place­ments.

“It is not un­com­mon,” she added, “to place lim­i­ta­tions on the pre­scrip­tion of cer­tain med­i­ca­tions to spe­cial­ist de­part­ments, eg cer­tain an­tibi­otics need ap­proval from mi­cro­bi­ol­ogy or in­fec­tious dis­eases.”

‘Un­nec­es­sary distress’

An­other ob­ser­va­tion made by the re­searchers is that those re­ceiv­ing TLPs as in­pa­tients “will be un­able to avail of it on the cur­rent Drug Pay­ment Scheme upon dis­charge. The prac­tice of com­menc­ing TLP in pa­tients who will be un­able to ac­cess them in the com­mu­nity causes un­nec­es­sary distress to pa­tients.”

Com­ment­ing fur­ther on this as­pect, Dr McCol­gan said lim­it­ing the pre­scrip­tion of TLPs to pain and anaes­thetic spe­cial­ties should re­duce the dis­crep­ancy be­tween in­pa­tient and out­pa­tient set­tings: “While re­cent pol­icy changes lim­it­ing the off-la­bel pre­scrip­tion of TLPs in the out­pa­tient set­ting are a pos­i­tive mea­sure, th­ese changes should be in­tro­duced across the en­tire health­care sys­tem.”

Dr McCol­gan re­it­er­ated that cur­rent ev­i­dence does not sup­port the use of TLPs for the man­age­ment of OA-as­so­ci­ated pain: “In­ter­na­tional ev­i­dence-based guide­lines such as the UK’s Na­tional In­sti­tute for Health and Care Ex­cel­lence, the Amer­i­can Academy of Or­thopaedics and the Euro­pean So­ci­ety for Clin­i­cal and Eco­nomic As­pects of Os­teo­poro­sis and Os­teoarthri­tis do not ad­vo­cate its use in OA. Ex­pen­di­ture lev­els on TLP in this coun­try are ex­ces­sive,” she said.

“Th­ese funds, she added, “are be­ing di­verted away from tack­ling im­por­tant is­sues in our health sys­tem, such as re­duc­ing the wait­ing list for ma­jor joint re­place­ment surgery, an in­ter­ven­tion that is proven to work.”

With no ev­i­dence sup­port­ing the use of TLPs to treat OA-as­so­ci­ated pain, it seems that this study has ex­posed a prac­tice that raises se­ri­ous fi­nan­cial im­pli­ca­tions for the health ser­vice.

If the pre­scrip­tion of TLP was lim­ited to anaes­thetic and pain con­sul­tants only, this should re­sult in a dra­matic re­duc­tion in in­ap­pro­pri­ate hos­pi­tal pre­scrib­ing

PHO­TO­GRAPH: ISTOCK

■ Arthri­tis is the sin­gle big­gest cause of dis­abil­ity in Ire­land, af­fect­ing al­most one mil­lion peo­ple.

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