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Clinical Experiences with Lidocaine as a Local Anesthetic
CLIN ICA L EXPERIENCES WITH LIDOCAINE AS A LO CA L ANESTHETIC* Ralph S. Lloyd.f D.D.S., and James O . Blythe, Jr.,f D.D.S., Baltimore
h a v e had the opportunity to test ob jectively a local anesthetic agen t w h ich has been developed in Sw eden. I t is called “ lidocaine” and m arketed u n der the trade nam e “ X ylo cain e.” E rd tm an and L ôfgren , in 1937, showed that a series of acetanilid d eriva tives displayed local anesthetic qualities. In subsequent investigations L ô fgren and L u n d q vist synthetized co-diethylamino2.6-dim ethylacetanilid, called “ L .L -3 0 ” or lidocaine, and fou n d that this com pound m ight be of clinical im portance as a local anesthetic. T h e new local a n esthetic agent was subjected to p h arm a cologic and clin ical investigations b y G old b erg and G ord h .1 D u rin g the last several m onths solu tions o f lidocaine anesthetic w ere tested in the fields o f m edicine, surgery and dentistry a t the U n ited States M a rin e H ospital, B altim ore, to determ ine its e f ficiency and to discover any u n tow ard results. F or the experim ent in the D en ta l Service it was decided that a 2 per cent solution o f lidocaine hydrochloride w ith 1:100,000 epinephrine w ou ld be used. T h is solution w ould be com pared w ith -a 2 per cent solution of procaine h yd ro chlorid e w ith nordefrin ( “ C ob efrin ” ) i : 10,000 w h ich is currently being used in the D en tal Service at ou r hospital. W e w ere using nordefrin as a vasocon strictor instead o f epinephrine because a series of patients exhibited un tow ard sym ptom s such as nervousness and syn cope w h en w e used epinephrine in 1:5 0 ,000 dilution as a vasoconstrictor. S o lu tions o f i : 10,000 nordefrin and 1 ¡50,000 epinephrine have approxim ately the sam e vasoconstricting pow er.2 e
W
.
296
In form u latin g the clinical experim ents it w as not planned th at all the cases in w h ich local anesthetics w ere used w ould be tabulated. D u rin g the course o f the experim ent lidocaine was adm inistered abou t 900 times. H ow ever, fo r tabulation w e selected as m any cases as possible in w h ich bilateral injections cou ld be given a t the sam e tim e. Procaine was then given on one side and lid ocaine on the other in order to elim inate the hum an factor. T h is seemed to us a fa ir w ay to com pare the efficiency and results of the anesthetic. W e tried n ot to let the patien t know th at an experim ent was in progress or th a t different anesthetics w ere used. T h e patients’ reactions w ere recorded before they w ere dismissed. L id o cain e was supplied in 1.8 cc. cart ridges and procaine was supplied in 2.4 cc. cartridges. Less than one cartridge was used fo r each injection. I t is esti m ated th at the average am ount o f lid o caine used was 60 per cent that o f p ro caine, both in infiltration and block anesthesia. In some cases only 0.75 cc. o f lidocaine w as used. T h e tim e from injection to operation or supposed depth of anesthesia was re corded, and the patients w ere asked to
*Xylocaine is the registered trade name in Sweden, with U . S. trademark application pending. fSenior dental surgeon, chief of D ental Service, U . S. M arine Hospital, Baltimore. fD en ta l surgeon, assistant to chief o f D ental Service, U . S. M arine Hospital, Baltimore. 1. Björn, H ., and H uldt, S., T h e Efficiency of Xylocaine as a Dental Term inal Anesthetic Compared to T h a t of Procaine. Svensk Tandläkare-Tidskrift 40:831, 1947. 2. Nevin, M ., and Puterbaugh, P. G ., Conduction, Infiltration and General Anesthesia in Dentistry, ed. 4. Brooklyn: Dental Items o f Interest Publishing C om pany, In c., pp. 262-278.
Lloyd-Blythe
A N E S T H E S IA
J .A .D .A ., V ol. 39, Septem b er 1949 . . . 29
1
NO. C A SES
UDOCAINE INFILTRATION PROCAINE INFILTRATION UDOCAINE CONDUCTION BLOCK PROCAINE CONDUCTION BLOCK
Fig. i . — Average time to redch depth of anesthesia
inform us w hen the anesthesia w ore off. T h e progress o f anesthesia produced by the tw o anesthetic solutions was de term ined both by questioning the patients and by testing the periodontal tissue w ith the point of an explorer or cotton plier. Six differen t dentists, fou r of w hom w ere interns, cooperated in this experi m ent. T h e dentist w as aw are o f the type of anesthetic b eing used, bu t he was cautioned not to inform the patients. T h e results of the experim ent w ere tabu lated and condensed into graphs (Figs. i and 2 ). W h en infiltrated, lidocaine produced
the d ep th of anesthesia approxim ately one m inute sooner than procaine. W hen used in nerve block, lidocaine produced the d ep th of anesthesia in less than h a lf of the tim e required by procaine. T h e tim e required for lidocaine to produce the d ep th o f anesthesia in nerve block w as less than the tim e required for pro caine to be effective w hen infiltrated. T h e average duration o f anesthesia w ith infiltration was approxim ately the same w ith lidocaine and procaine. T h e duration of anesthesia fo r lidocaine block w as apparently one hour longer' than procaine block.
NO. CASES
LIDOCAINE INFILTRATION PROCAINE INFILTRATION LIDOCAINE CONDUCTION BLOCK
17
PROCAINE CONDUCTION BLOCK
Fig. 2.— Average duration of anesthesia
298
The Jo u rn al o f th e A m erican D ental A ssociation
Limits of time required for induction of depth of anesthesia
duced on the side in w h ich lidocaine was given. 2. Som e patients com plained th at the side in w hich lidocaine w as used was cold and felt “ w ooden” or “ hard as a b rick.” Som e said the anesthesia was too dense. T h is w as given as an objection. 3. S everal patients said there was no pain on thé side in w h ich lidocaine was used and th at there Was some pain on th e opposite side, in w h ich procaine was used. 4. W hen lidocaine had been used previously, some patients requested that the operator give h im “ the stu ff you gave m e the other tim e.” 5. O n e patien t w h o h a d a severe toothach e from acu te pulpitis was re lieved in 60 seconds by the injection of lidocaine. 6. T w o patients experienced m ore pain on the side in w hich lidocaine was used. 7. O n the w hole, lidocaine was m uch m ore effective in the drilling experim ents than procaine. Several patients com plained of pain caused by d rilling and air w hen procaine was used. O n ly one patien t com plained of slight pain from d rilling and air w hen lidocaine was used, bu t in one case it was necessary to w ait five m inutes fo r com plete anesthesia. It is the general opinion of the den tists w ho p articip ated in th e experim ent that lidocaine is an effective local anes thetic. I t seems to h ave some advantages over procain e w ith n ordefrin and, ap parently, its objectionable characteristics are not greater. It is believed th at lid o caine w arrants fu rther trial as a dental anesthetic.
Anesthesia Infiltration Lidocaine Procaine Block Lidocaine Procaine
Shortest time
Longest time
25 sec. I min.
3 min., 40 sec. 4 min., 50 sec.
45 sec. 2 mm.
7 min., 15 sec. 7 min., 45 sec.
T h e upper and low er lim its o f tim e required to reach depth of anesthesia are shown in the table. T h e anesthesia w h ich w as produced by lid ocaine was profound. I t was a com m on observation o f patients th at the numbness was m arked and that they did not feel a thing. T h e d ep th of anesthesia obtained w ith lid ocaine was apparently greater than the depth o f anesthesia ob tained w ith procaine. S ligh t sensationwas often reported b y patients w hen procain e w as used. In three patients, p ain fu l superficial ulceration developed a t the point o f in jection . L id o cain e had been used in tw o of these cases, procaine in one. L id ocain e was used tw ice as often as procaine. T w o patients fain ted im m ediately after the anesthetic was injected. O n e of these patients h a d lidocaine, and the oth er had procaine one d ay and lid o caine the n ext day. A t the tim e, these reactions w ere thou ght to be due to psychic causes. Som e typical reactions o f the patients w ho h a d lidocaine injected on one side and procain e on the oth er sim ultaneously are as follow s: i.
M o re profound anesthesia was in
h a v e had the opportunity to test ob jectively a local anesthetic agen t w h ich has been developed in Sw eden. I t is called “ lidocaine” and m arketed u n der the trade nam e “ X ylo cain e.” E rd tm an and L ôfgren , in 1937, showed that a series of acetanilid d eriva tives displayed local anesthetic qualities. In subsequent investigations L ô fgren and L u n d q vist synthetized co-diethylamino2.6-dim ethylacetanilid, called “ L .L -3 0 ” or lidocaine, and fou n d that this com pound m ight be of clinical im portance as a local anesthetic. T h e new local a n esthetic agent was subjected to p h arm a cologic and clin ical investigations b y G old b erg and G ord h .1 D u rin g the last several m onths solu tions o f lidocaine anesthetic w ere tested in the fields o f m edicine, surgery and dentistry a t the U n ited States M a rin e H ospital, B altim ore, to determ ine its e f ficiency and to discover any u n tow ard results. F or the experim ent in the D en ta l Service it was decided that a 2 per cent solution o f lidocaine hydrochloride w ith 1:100,000 epinephrine w ou ld be used. T h is solution w ould be com pared w ith -a 2 per cent solution of procaine h yd ro chlorid e w ith nordefrin ( “ C ob efrin ” ) i : 10,000 w h ich is currently being used in the D en tal Service at ou r hospital. W e w ere using nordefrin as a vasocon strictor instead o f epinephrine because a series of patients exhibited un tow ard sym ptom s such as nervousness and syn cope w h en w e used epinephrine in 1:5 0 ,000 dilution as a vasoconstrictor. S o lu tions o f i : 10,000 nordefrin and 1 ¡50,000 epinephrine have approxim ately the sam e vasoconstricting pow er.2 e
W
.
296
In form u latin g the clinical experim ents it w as not planned th at all the cases in w h ich local anesthetics w ere used w ould be tabulated. D u rin g the course o f the experim ent lidocaine was adm inistered abou t 900 times. H ow ever, fo r tabulation w e selected as m any cases as possible in w h ich bilateral injections cou ld be given a t the sam e tim e. Procaine was then given on one side and lid ocaine on the other in order to elim inate the hum an factor. T h is seemed to us a fa ir w ay to com pare the efficiency and results of the anesthetic. W e tried n ot to let the patien t know th at an experim ent was in progress or th a t different anesthetics w ere used. T h e patients’ reactions w ere recorded before they w ere dismissed. L id o cain e was supplied in 1.8 cc. cart ridges and procaine was supplied in 2.4 cc. cartridges. Less than one cartridge was used fo r each injection. I t is esti m ated th at the average am ount o f lid o caine used was 60 per cent that o f p ro caine, both in infiltration and block anesthesia. In some cases only 0.75 cc. o f lidocaine w as used. T h e tim e from injection to operation or supposed depth of anesthesia was re corded, and the patients w ere asked to
*Xylocaine is the registered trade name in Sweden, with U . S. trademark application pending. fSenior dental surgeon, chief of D ental Service, U . S. M arine Hospital, Baltimore. fD en ta l surgeon, assistant to chief o f D ental Service, U . S. M arine Hospital, Baltimore. 1. Björn, H ., and H uldt, S., T h e Efficiency of Xylocaine as a Dental Term inal Anesthetic Compared to T h a t of Procaine. Svensk Tandläkare-Tidskrift 40:831, 1947. 2. Nevin, M ., and Puterbaugh, P. G ., Conduction, Infiltration and General Anesthesia in Dentistry, ed. 4. Brooklyn: Dental Items o f Interest Publishing C om pany, In c., pp. 262-278.
Lloyd-Blythe
A N E S T H E S IA
J .A .D .A ., V ol. 39, Septem b er 1949 . . . 29
1
NO. C A SES
UDOCAINE INFILTRATION PROCAINE INFILTRATION UDOCAINE CONDUCTION BLOCK PROCAINE CONDUCTION BLOCK
Fig. i . — Average time to redch depth of anesthesia
inform us w hen the anesthesia w ore off. T h e progress o f anesthesia produced by the tw o anesthetic solutions was de term ined both by questioning the patients and by testing the periodontal tissue w ith the point of an explorer or cotton plier. Six differen t dentists, fou r of w hom w ere interns, cooperated in this experi m ent. T h e dentist w as aw are o f the type of anesthetic b eing used, bu t he was cautioned not to inform the patients. T h e results of the experim ent w ere tabu lated and condensed into graphs (Figs. i and 2 ). W h en infiltrated, lidocaine produced
the d ep th of anesthesia approxim ately one m inute sooner than procaine. W hen used in nerve block, lidocaine produced the d ep th of anesthesia in less than h a lf of the tim e required by procaine. T h e tim e required for lidocaine to produce the d ep th o f anesthesia in nerve block w as less than the tim e required for pro caine to be effective w hen infiltrated. T h e average duration o f anesthesia w ith infiltration was approxim ately the same w ith lidocaine and procaine. T h e duration of anesthesia fo r lidocaine block w as apparently one hour longer' than procaine block.
NO. CASES
LIDOCAINE INFILTRATION PROCAINE INFILTRATION LIDOCAINE CONDUCTION BLOCK
17
PROCAINE CONDUCTION BLOCK
Fig. 2.— Average duration of anesthesia
298
The Jo u rn al o f th e A m erican D ental A ssociation
Limits of time required for induction of depth of anesthesia
duced on the side in w h ich lidocaine was given. 2. Som e patients com plained th at the side in w hich lidocaine w as used was cold and felt “ w ooden” or “ hard as a b rick.” Som e said the anesthesia was too dense. T h is w as given as an objection. 3. S everal patients said there was no pain on thé side in w h ich lidocaine was used and th at there Was some pain on th e opposite side, in w h ich procaine was used. 4. W hen lidocaine had been used previously, some patients requested that the operator give h im “ the stu ff you gave m e the other tim e.” 5. O n e patien t w h o h a d a severe toothach e from acu te pulpitis was re lieved in 60 seconds by the injection of lidocaine. 6. T w o patients experienced m ore pain on the side in w hich lidocaine was used. 7. O n the w hole, lidocaine was m uch m ore effective in the drilling experim ents than procaine. Several patients com plained of pain caused by d rilling and air w hen procaine was used. O n ly one patien t com plained of slight pain from d rilling and air w hen lidocaine was used, bu t in one case it was necessary to w ait five m inutes fo r com plete anesthesia. It is the general opinion of the den tists w ho p articip ated in th e experim ent that lidocaine is an effective local anes thetic. I t seems to h ave some advantages over procain e w ith n ordefrin and, ap parently, its objectionable characteristics are not greater. It is believed th at lid o caine w arrants fu rther trial as a dental anesthetic.
Anesthesia Infiltration Lidocaine Procaine Block Lidocaine Procaine
Shortest time
Longest time
25 sec. I min.
3 min., 40 sec. 4 min., 50 sec.
45 sec. 2 mm.
7 min., 15 sec. 7 min., 45 sec.
T h e upper and low er lim its o f tim e required to reach depth of anesthesia are shown in the table. T h e anesthesia w h ich w as produced by lid ocaine was profound. I t was a com m on observation o f patients th at the numbness was m arked and that they did not feel a thing. T h e d ep th of anesthesia obtained w ith lid ocaine was apparently greater than the depth o f anesthesia ob tained w ith procaine. S ligh t sensationwas often reported b y patients w hen procain e w as used. In three patients, p ain fu l superficial ulceration developed a t the point o f in jection . L id o cain e had been used in tw o of these cases, procaine in one. L id ocain e was used tw ice as often as procaine. T w o patients fain ted im m ediately after the anesthetic was injected. O n e of these patients h a d lidocaine, and the oth er had procaine one d ay and lid o caine the n ext day. A t the tim e, these reactions w ere thou ght to be due to psychic causes. Som e typical reactions o f the patients w ho h a d lidocaine injected on one side and procain e on the oth er sim ultaneously are as follow s: i.
M o re profound anesthesia was in