Pre­scrip­tion drugs

Side ef­fects ver­sus out­comes

The Irish Times - Tuesday - Health - - Front Page - Dr Muiris Hous­ton

My ex­pe­ri­ence as a pa­tient pre­scribed the drug Pre­ga­balin (Lyrica) – Med­i­cal Mat­ters, Oc­to­ber 25th, 2016 – sparked a con­sid­er­able reader re­ac­tion. You re­sponded to my ex­pe­ri­ence of feel­ing an un­pleas­ant “muzzi­ness” in my head while tak­ing the drug. And my de­scrip­tion of re­duc­ing the dose also struck a chord:

“Some strange symp­toms emerged. I de­vel­oped aches and pains all over, as you would with a dose of the flu. The muzzi­ness became a strange kind of float­ing feel­ing ac­com­pa­nied by in­ter­mit­tent dizzy spells. And I felt in­cred­i­bly tense, as if pres­sure was build­ing up in­side my head.”

The col­umn also trig­gered a re­sponse from med­i­cal col­leagues. A Dublin GP said, “I have had mul­ti­ple prob­lems with its [pre­ga­balin] price, its gas­troin­testi­nal side ef­fects, its weight prob­lems and its titra­tion down­wards.”

Dr Ea­mon Shana­han, a GP in Far­ran­fore, Co Kerry, kindly searched his prac­tice data­base and reck­ons about 2-5 per cent of pa­tients tak­ing pre­ga­balin ex­pe­ri­ence a side ef­fect. “Look­ing down the list of pa­tients who are tak­ing pre­ga­balin, the vast ma­jor­ity of those were given it for neu­ro­pathic pain,” he said.

Lin­ger­ing pain post shin­gles in­fec­tion was the most com­mon rea­son read­ers said they were tak­ing Lyrica. One man in his 70s ex­pe­ri­enced good pain re­lief in the first week, but then no­ticed quite spe­cific prob­lems with his mem­ory. He was es­pe­cially upset at not be­ing able to re­mem­ber prayers and po­ems he has re­cited since he was a child.

With­drawal symp­toms

A wo­man who was told to come off Lyrica “cold turkey” said she nearly “went mad” with with­drawal symp­toms, in­clud­ing aches all over, shiv­ers, cry­ing and light­head­ed­ness. Another reader said she was in a haze while tak­ing the drug. “I de­scribed it at the time as feel­ing drunk at all times – my think­ing was com­pro­mised.”

Mean­while, another cor­re­spon­dent praised Lyrica for en­abling her to sleep de­spite pain “but within a month I no­ticed that I felt ‘not quite with it’, as if I was walk­ing round in a fog. This got worse, to the point where it was af­fect­ing my work.” How­ever, she had no prob­lem com­ing off the drug.

For a younger man, even though Lyrica didn’t erad­i­cate his back pain, “I ac­tu­ally did not care be­cause I felt re­ally good. It was like be­ing in a fog com­pletely stoned.” He was em­phatic he wouldn’t take the med­i­ca­tion again.

A grand­mother with low back pain said she stopped Lyrica with­out any wean­ing: “I def­i­nitely no­ticed an im­me­di­ate re­ac­tion – not in pain levels [slightly up] but in mood. I was most def­i­nitely de­pressed, thank­fully not for long, a few weeks]. . . I felt very low, a cloud of sad­ness hung over me and I was close to tears a lot.”

Another reader, tak­ing a small dose at night, said she felt “dopey” and spaced out in the morn­ing. “As you de­scribed, I thought my head would ex­plode and only I have low blood pres­sure I would have thought I was about to have a stroke. The slight­est stress raised anx­i­ety levels.”

An 88-year-old man said Lyrica did not elim­i­nate pain but al­lowed him sit com­fort­ably. How­ever, he felt he was faced with Hob­son’s Choice given the side ef­fects he ex­pe­ri­enced which in­cluded se­vere con­sti­pa­tion, dizzi­ness, tremor, weight gain and sleep dis­tur­bance.


My de­scrip­tion of muzzi­ness res­onated with a num­ber of cor­re­spon­dents. “I couldn’t con­tinue with the muzzi­ness and gen­eral pe­cu­liar feel­ing in my head which you de­scribed so well,” said one.

A re­tiree who went back to study got a shock when he sat an exam while pre­scribed Lyrica: “I was sur­prised by how I felt dur­ing the writ­ten exam – my writ­ing was aw­ful, my think­ing was slow even though the pa­per suited me. Your word ‘muzzi­ness’ is the best I can use to describe it. I was phys­i­cally ex­hausted af­ter­wards.”

While some of the sto­ries you shared res­onated with mine, oth­ers wrote to say how they had no prob­lems when pre­scribed Lyrica – as was the case for this wo­man with post shin­gles pain:

“I found them ex­tremely ef­fec­tive, and stopped them once I no longer needed them. I no­ticed no side ef­fects, and had no with­drawal prob­lems. I was very con­scious of this, as a friend of mine had been pre­scribed them af­ter back surgery and found the side ef­fects so bad she stopped im­me­di­ately.”

A 69-year-old male started tak­ing Lyrica in 2009 and stopped abruptly last year. He went from a dose of 150mg three times a day to zero “and since then have had no re­ac­tion that I am aware of”. And a 91-year-old said of his two years tak­ing pre­ga­balin – “Works and no side ef­fects.”

Mean­while, a 66-year-old cor­re­spon­dent said Lyrica pre­scribed for her resid­ual pain af­ter shin­gles “worked very well. Was only mildly woozy for a day or two at first. So was pleased with out­come.”

A cou­ple of read­ers de­scribed clas­sic al­ler­gic re­ac­tions to the drug, com­plete with swelling of the tongue and an ex­ten­sive skin rash, which set­tled once they stopped tak­ing pre­ga­balin.

For some cor­re­spon­dents, the drug sim­ply didn’t work. A wo­man who was pre­scribed Lyrica af­ter a bout of shin­gles said: “It isn’t re­ally do­ing any­thing to al­le­vi­ate the pain so I’m think­ing of com­ing off it, fol­low­ing my next con­sul­ta­tion with my doc­tor. I don’t at all like the ‘zom­bie’-like feel­ing it gives me.”

Drugs not work­ing and caus­ing al­ler­gic re­ac­tions are, of course, not unique to pre­ga­balin. Re­search sug­gests that, in gen­eral, med­i­ca­tion for chronic pain tends not to work in the longer term.


Ac­cord­ing to the Euro­pean Medicines Agency (EMA), in 10 stud­ies in­volv­ing more than 3,000 pa­tients with pe­riph­eral neu­ro­pathic pain, 35 per cent of pa­tients treated with Lyrica had a de­crease in pain scores of 50 per cent or more, com­pared with 18 per cent of the pa­tients treated with placebo.

In a smaller study in­volv­ing 137 pa­tients with cen­tral neu­ro­pathic pain due to a spinal cord in­jury, 22 per cent of pa­tients treated with Pfizer’s ver­sion of the drug had a de­crease in pain scores of 50 per cent or more, com­pared with 8 per cent of the pa­tients treated with placebo.

In the Repub­lic, the Health Prod­ucts Reg­u­la­tory Agency (HPRA) has re­ceived 303 re­ports of sus­pected ad­verse events and events as­so­ci­ated with the use of Lyrica – from the time the drug was first au­tho­rised in 2004 up to the end of Novem­ber 2016. Just over a half oc­curred in fe­males.

Ac­cord­ing to the agency’s direc­tor of hu­man medicines, Dr Joan Gil­varry, the ma­jor­ity of re­ports re­ceived by the HPRA have been con­sis­tent with the ex­pected pat­tern of ad­verse ef­fects for the drug.

“Gas­troin­testi­nal and ner­vous sys­tem dis­or­ders, such as vom­it­ing, nau­sea, di­ar­rhoea, dizzi­ness and headache, have been among the most com­monly re­ported ef­fects.

Other com­monly re­ported symp­toms in­clude malaise, headache, dizzi­ness, som­no­lence and tremor,” she told The Ir­ish Times.

“There have also been some re­ports de­scrib­ing psy­chi­atric-type re­ac­tions such as anx­i­ety, con­fu­sion, hal­lu­ci­na­tion and drug abuse or de­pen­dence. Is­sues with drug with­drawal have also been re­ported.”

In gen­eral, pa­tients were pre­scribed Lyrica for ei­ther neu­ro­pathic pain or gen­er­alised anx­i­ety dis­or­der, she added.

Abuse con­cerns

There is con­cern among GPs and doc­tors work­ing in ad­dic­tion medicine about pre­ga­balin’s grow­ing pop­u­lar­ity as a drug of abuse. Usu­ally part of mul­ti­ple drug ad­dic­tion, pre­ga­balin is also a primary ad­dic­tive sub­stance and wean­ing ad­dicts off it is dif­fi­cult. There has been a five-fold in­crease in the num­ber of re­ports of “abuse”, “mis­use” and “de­pen­dence” for gabapenti­noids as part of ad­verse drug re­ac­tion re­port­ing in the UK since 2010. Re­searchers from the Na­tional Drug Treat­ment Cen­tre, writ­ing in the Ir­ish Med­i­cal Jour­nal last Jan­uary, flagged their con­cerns about pre­ga­balin.

“Our study [which showed a mis­use rate of 7 per cent] con­firms that pre­ga­balin abuse is tak­ing place among the ad­dic­tion ser­vices pop­u­la­tion. We be­lieve that mis­use of this pre­scrip­tion drug is a se­ri­ous emerg­ing is­sue which should be mon­i­tored care­fully.”

It’s a point echoed by Dr Shana­han: “Given that pre­ga­balin has a street value and there are case re­ports of de­pen­dence, fur­ther work needs to be done to min­imise th­ese out­comes.”

Asked if the com­pany had been ap­proached by ei­ther the HPRA or Euro­pean reg­u­la­tors with con­cerns about ei­ther the side ef­fects or ad­dic­tion po­ten­tial of Lyrica, a spokes­women for Pfizer said: “Pfizer re­views all safety data on Lyrica with the Euro­pean reg­u­la­tors in ac­cor­dance with leg­isla­tive and reg­u­la­tory re­quire­ments. The Sum­mary of Prod­uct Char­ac­ter­is­tics presents the rel­e­vant in­for­ma­tion for doc­tors to pre­scribe Lyrica ap­pro­pri­ately.”

She also con­firmed that the pre­scrib­ing of Lyrica was not re­stricted to specialist doc­tors any­where in the Euro­pean Union.

Pfizer and the man­u­fac­tur­ers of generic pre­ga­balin are obliged to con­duct post-mar­ket­ing sur­veil­lance of the drug.

Given the drug’s ad­dic­tion po­ten­tial, in par­tic­u­lar, it would be help­ful if the phar­ma­ceu­ti­cal firms could deepen this data col­lec­tion and share the re­sults di­rectly with con­sumers (as well as with reg­u­la­tors).

Such a move would add a fur­ther layer of pa­tient safety for those le­git­i­mately pre­scribed pre­ga­balin and other gabapenti­noids.

* I would like to thank the many read­ers who took the time to share their ex­pe­ri­ences with me.

There have been re­ports de­scrib­ing psy­chi­atric-type re­ac­tions such as anx­i­ety, con­fu­sion, hal­lu­ci­na­tion and drug abuse or de­pen­dence, as well as is­sues with drug with­drawal

The Health Prod­ucts Reg­u­la­tory Agency has re­ceived 303 re­ports of sus­pected ad­verse events and events as­so­ci­ated with the use of Lyrica. Just over a half oc­curred in fe­males.

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