A comparison of buprenorphine and pentazocine for the relief of
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SAMJ VOLUME 69 4 JANUARY 1986 27 A comparison of buprenorphine and pentazocine for the relief of postoperative pain M. FREEDMAN Summary The analgesic potency, efficacy, duration of action and side-effects of buprenorphine (Temgesic) 0,3 mg and 0,6 mg were compared with those of pentazocine (Sosegon) 30 mg and 60 mg in 100 - male patients who had undergone orthopaedic surgical procedures. The drugs were given by intra- muscular injection 30 minutes before completion of the surgical procedure, and the quality of pain relief and incidence of side-effects were assessed at 30- minute intervals for at least 6 hours. Buprenorphine was shown to be safe, to be more potent and to have a longer duration of action than pentazocine, and to result in less nausea, vomiting and euphoria. but it was associated with a higher incidence of postoperative sedation than pen1azocine. S AIr lied J 19116; -= 27-28. the upper and lower limbs. All patients underwent a routine clinical examination before surgery and were judged to be fit for operation. Informed consent was obtained from eveey patient. Apart from the limitation that no narcotics were employed in the premedication or during surgery, no other restrictions were placed upon the anaesthetic technique. The patients were divided by blind random allocation into one of four groups, and received either pentazocine 30 mg, pentazocine 60 mg, buprenorphine 0,3 mg or buprenorphine 0,6 mg as an intramuscular injection approxi- mately 30 minutes before the completion of surgery. We considered it unethical to use a placebo control group. No atrempt was made to adjust the dose of the drug allocated according to the age or weight of the patient. Each dose was made up in an identical 2 ml syringe, neither the anaesthetist, the surgeon nor the patient being aware of which drug was being injected. Postoperatively all patients were transferred to the recovery room and the heart rate, blood pressure, respiratory rate, pupil size and level of consciousness recorded. All patients were returned to the ward within 60 minutes of receiving the narcotic analgesic. In the ward, pain was assessed subjectively by a trained medical orderly every 30 minutes for at least 6 hours. Each patient's pain was recorded on a scale of 0- 10 by their response to a visual analogue pain scale 4 .' (Fig. I). Fig. 1. A pain score was obtained by measuring the distance in centimetres between the mark made by each patient and the left- hand margin of this 10 cm long visual analogue pain scale. All side-effects, in particular hallucinations, dysphoria and euphoria, were noted. The nursing staff were informed that the patient had received an analgesic before h:aving the operating theatre, but were unaware of the nature or dose of the drug. Additional analgesia was given on patient request or when the sister on duty decided that a further dose of analgesic was needed. Once an additional dose of analgesic was given, the patient was considered for the purpose of the trial to have zero pain relief and was allocated a pain score of 10. The results obtained from the four groups at I hour, 3 hours and 6 hours after administration of the analgesic were compared using simple statistical methods. The Kruskall-Wallis one-way analysis of variance (P < 0,001) and median tests were used to compare the groups. Pairwise comparisons of treatment groups were made by using the Marm-Whitney U-test. Pentazocine (Sosegon), a synthetic partial agonist-antagonist compound, is one of the most widely available analgesics administered outside major medical centres. It has the theoreti- cal advantage of being safe when administered by trained paramedical personnel, and has been thought to be less addic- tive and possibly to cause less euphoria than other narcotics. However, its relatively slow onset of action, low potency and poor efficacy and short duration of action, and its side-effects, which include nausea, vomiting and dizziness, have prompted the search for new powerful analgesics. Clinical trials of the pharmacodynamic properties of buprenorphine have shown it to be a safe, potent long-acting analgesic. -3 A clinical trial was designed to explore further the possibili- ties of using this drug after surgery when patients are initially attended by trained paramedical personnel. This was done by constructing a comparative study in a selected group of patients using pentazocine and buprenorphine, both drugs being administered by intramuscular injection. Patients and methods The trial was conducted on 100 men aged 16 - 40 years, under- going elective and emergency orthopaedic procedures under general anaesthesia involving open reduction and fixation of fractures of No pain Worst pain Department of Anaesthesia, 1 Military Hospital, Voortrekkerhoogte, Pretoria M. FREEDMAN, M.B. B.CH., D.A. (S.A.), F.F.A. (S.A.), Specialise Anaeseheeise Results A pain score of < 2,5 was considered to represent good pain relief, while a score of> 7,5 was considered to represent severe pain. The mean-ranked pain scores obtained for each of the buprenor- phine groups were lower than those obtained for the pentazocine groups. This difference was not significant at I hour, but was
Transcript of A comparison of buprenorphine and pentazocine for the relief of
SAMJ VOLUME 69 4 JANUARY 1986 27
A comparison of buprenorphineand pentazocine for the relief ofpostoperative painM. FREEDMAN
Summary
The analgesic potency, efficacy, duration of actionand side-effects of buprenorphine (Temgesic) 0,3mg and 0,6 mg were compared with those ofpentazocine (Sosegon) 30 mg and 60 mg in 100
- male patients who had undergone orthopaedicsurgical procedures. The drugs were given by intramuscular injection 30 minutes before completion ofthe surgical procedure, and the quality of pain reliefand incidence of side-effects were assessed at 30minute intervals for at least 6 hours.
Buprenorphine was shown to be safe, to be morepotent and to have a longer duration of action thanpentazocine, and to result in less nausea, vomitingand euphoria. but it was associated with a higherincidence of postoperative sedation than pen1azocine.
S AIr lied J 19116; -= 27-28.
the upper and lower limbs. All patients underwent a routineclinical examination before surgery and were judged to be fit foroperation. Informed consent was obtained from eveey patient.
Apart from the limitation that no narcotics were employed inthe premedication or during surgery, no other restrictions wereplaced upon the anaesthetic technique. The patients were dividedby blind random allocation into one of four groups, and receivedeither pentazocine 30 mg, pentazocine 60 mg, buprenorphine 0,3mg or buprenorphine 0,6 mg as an intramuscular injection approximately 30 minutes before the completion of surgery. We consideredit unethical to use a placebo control group. No atrempt was madeto adjust the dose of the drug allocated according to the age orweight of the patient. Each dose was made up in an identical 2 mlsyringe, neither the anaesthetist, the surgeon nor the patient beingaware of which drug was being injected.
Postoperatively all patients were transferred to the recoveryroom and the heart rate, blood pressure, respiratory rate, pupilsize and level of consciousness recorded. All patients were returnedto the ward within 60 minutes of receiving the narcotic analgesic.
In the ward, pain was assessed subjectively by a trained medicalorderly every 30 minutes for at least 6 hours. Each patient's painwas recorded on a scale of 0 - 10 by their response to a visualanalogue pain scale4
.' (Fig. I).
Fig. 1. A pain score was obtained by measuring the distance incentimetres between the mark made by each patient and the lefthand margin of this 10 cm long visual analogue pain scale.
All side-effects, in particular hallucinations, dysphoria andeuphoria, were noted. The nursing staff were informed that thepatient had received an analgesic before h:aving the operatingtheatre, but were unaware of the nature or dose of the drug.
Additional analgesia was given on patient request or when thesister on duty decided that a further dose of analgesic was needed.Once an additional dose of analgesic was given, the patient wasconsidered for the purpose of the trial to have zero pain relief andwas allocated a pain score of 10.
The results obtained from the four groups at I hour, 3 hoursand 6 hours after administration of the analgesic were comparedusing simple statistical methods. The Kruskall-Wallis one-wayanalysis of variance (P < 0,001) and median tests were used tocompare the groups. Pairwise comparisons of treatment groupswere made by using the Marm-Whitney U-test.
Pentazocine (Sosegon), a synthetic partial agonist-antagonistcompound, is one of the most widely available analgesicsadministered outside major medical centres. It has the theoretical advantage of being safe when administered by trainedparamedical personnel, and has been thought to be less addictive and possibly to cause less euphoria than other narcotics.However, its relatively slow onset of action, low potency andpoor efficacy and short duration of action, and its side-effects,which include nausea, vomiting and dizziness, have promptedthe search for new powerful analgesics.
Clinical trials of the pharmacodynamic properties ofbuprenorphine (Tem~esic) have shown it to be a safe, potentlong-acting analgesic. -3
A clinical trial was designed to explore further the possibilities of using this drug after surgery when patients are initiallyattended by trained paramedical personnel. This was done byconstructing a comparative study in a selected group of patientsusing pentazocine and buprenorphine, both drugs beingadministered by intramuscular injection.
Patients and methods
The trial was conducted on 100 men aged 16 - 40 years, undergoing elective and emergency orthopaedic procedures under generalanaesthesia involving open reduction and fixation of fractures of
No pain Worst pain
Department of Anaesthesia, 1 Military Hospital,Voortrekkerhoogte, PretoriaM. FREEDMAN, M.B. B.CH., D.A. (S.A.), F.F.A. (S.A.), SpecialiseAnaeseheeise
Results
A pain score of < 2,5 was considered to represent good pain relief,while a score of> 7,5 was considered to represent severe pain.
The mean-ranked pain scores obtained for each of the buprenorphine groups were lower than those obtained for the pentazocinegroups. This difference was not significant at I hour, but was
28 SAMT DEEL 69 4 JANUARIE 1986
significant at 3 and 6 hours (P = 0,0036 and P = 0,0016)respectively.
However, many more patients in the pentazocine group (20%)than in the buprenorphine group (8%) had pain scores of> 7,5 atI hour. This difference is statistically significant.
As time elapsed, the superiority of buprenorphine over pentazocine was increasingly evident; 3 hours after administration, 62%of patients who had received pentazocine experienced severe pain,compared with 24% who had received buprenorphine, while after6 hours 58% of patients who had received buprenorphine still hadadequate pain relief, compared with 30% who had receivedpentazocine (Table I).
TABLE I. PAIN RELIEF* AT 1, 3 AND 6 HOURS
Pentazocine Buprenorphine
Pain score 30mg 60 mg 0,3 mg 0,6mg
1 hour0-2,5 16 16 19 192,6 - 7,5 4 4 3 5>7,5 5 5 3 1
3 hours0-2,5 6 6 12 112,6 - 7,5 4 3 6 9>7,5 15 16 7 5
6 hours0-2,5 2 4 9 112,6 - 7,5 "5 4 6 3>7,5 18 17 10 11
• 0 - 2,5 =good; 2,6 - 7,5 = moderate; > 7,5 = poor.
We were unable to demonstrate any significant differencebetween pentazocine 30 mg and pentazocine 60 mg or betweenbuprenorphine 0,3 mg and buprenorphine 0,6 mg at any of thetime intervals.
Buprenorphine 0,6 mg was superior to pentazocine 30 mg at allthree time intervals (P = 0,1658, P = 0,0042 and P = 0,0017respectively), whereas buprenorphine 0,3 mg gave significantlybener pain relief than pentazocine 60 mg at 3 and 6 hours (P =0,0316 and P = 0,0171).
Side-effectsSeven patients who received buprenorphine 0,6 mg and 6 who
received buprenorphine 0,3 mg were deeply sedated postoperatively. One patient who received buprenorphine 0,3 mgvomited postoperatively. No patient who received buprenorphineexperienced dysphoria or hallucinations.
In contrast, 5 patients who received pentazocine 60 mg and 4who received pentazocine 30 mg were deeply sedated, 3 patientswho received pentazocine 30 mg vomited, and I patient who
received pentazocine 60 mg and 3 who received pentazocine 30 mgexperienced hallucinations.
Discussion
Pain relief after acute trauma and after surgical procedures hasalways been of great concern to those anending to thesepatients. Although a large number of analgesic agents arepotentially available for the management of acute severe pain,much unnecessary suffering takes place.6
,7 The fear of addictionand side-effects has led to a limited arsenal of drugs beingavailable to paramedical personnel involved in the first line oftreatment. The introduction of a potent, non-addictive analgesicwith few serious side-effects would be a great advance.
Buprenorphine has been shown to be an effective analgesicagent, bener than pentazocine in the doses used and at thetimes chosen in this trial. The onset of analgesia was notdelayed with either drug. There was a low incidence of sideeffects other than sedation. A 0,3 mg dose of buprenorphine issufficient in most cases, suggesting that a second dose needonly be resorted to if the initial dose provides inadequateanalgesia.
The absence of psychotomimetic side-effects is notable,since these are considered to occur quite frequently withpentazocine.
I t would seem that the incidence of hallucinations, nauseaand vomiting was more closely correlated with severe painthan with a particular agent. In our experience respiratorydepression was not a problem, even when a high dose ofbuprenorphine (0,6 mg) was administered to a small patient(43 kg).
Sedation, as evidenced by difficulty in waking the patient,occurred most frequently with the higher dose of buprenorphine, but responded well to intravenous naloxone 0,4 mg.
The author is grateful to his colleagues Drs R. G. van Renen,A. P. Coetzer, H. Ingram and J. Smuts and to the medical orderlyobservers. Buprenorphine was supplied by Reckin & Colman,Pharmaceutical Division.
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