In the present study, the rhizome essential oil from Zingiber zerumbet (Zingiberaceae) was evaluated for antinociceptive activity using chemical and thermal models of nociception, namely, the acetic acid-induced abdominal writhing test, the hot-plate test and the formalin-induced paw licking test. It was demonstrated that intraperitoneal administration of the essential oil of Z. zerumbet (EOZZ) at the doses of 30, 100 and 300 mg/kg produced significant dose-dependent inhibition of acetic acid-induced abdominal writhing, comparable to that of obtained with acetylsalicylic acid (100 mg/kg). At the same doses, the EOZZ produced significant dose-dependent increases in the latency time in the hot-plate test with respect to controls, and in the formalin-induced paw licking test, the EOZZ also significantly reduced the painful stimulus in both neurogenic and inflammatory phase of the test. In addition, the antinociceptive effect of the EOZZ in the formalin-induced paw licking test as well as hot-plate test was reversed by the nonselective opioid receptor antagonist, naloxone suggesting that the opioid system was involved in its analgesic mechanism of action. On the basis of these data, we concluded that the EOZZ possessed both central and peripheral antinociceptive activities which justifying its popular folkloric use to relieve some pain conditions.
Elephantopus tomentosus is widely used in Asia, especially in Malaysia, for the treatment of pain and inflammation. In the present study, the analgesic and anti-inflammatory effects of a 95% ethanol extract of E. tomentosus were investigated in different experimental models. In the anti-inflammation study, 1000 mg/kg of extract significantly reduced carrageenan-induced hind paw edema (p < 0.05) and inhibited abdominal permeability compared with control (p < 0.01). The analgesic activity was assayed in several experimental models in mice: (1) hot plate, (2) tail flick, (3) writhing test; and rats: carrageenan-induced hyperalgesia pain threshold test. However, at the doses tested, no significant activity was found in the hot plate test and the tail flick test. E. tomentosus ethanol extract at 1000 mg/kg significantly (p < 0.05) increased hyperalgesia pain threshold and inhibited writhing activity. The results suggest that E. tomentosus ethanol extract at 1000 mg/kg dose is effective in anti-inflammatory and non-steroidal anti-inflammatory drug type anti-nociception activities.
The ethanolic extract of Alpinia conchigera Griff. leaves (EACL) was evaluated for its antinociceptive and anti-inflammatory activities in several in vivo experimental models. Antinociceptive activity was determined using the acetic acid-induced abdominal writhing test, the hot plate test and the formalin test. Anti-inflammatory activity was determined using the carrageenan-induced paw edema test. The extract (30, 100 and 300 mg/kg i.p.) was found to possess significant, dose-dependent inhibitory activity in all test models. In addition, the antinociceptive effect of the extract in the acetic acid-induced writhing and hot plate tests was reversed by naloxone, suggesting that this activity is mediated through activation of the opioid system. These findings suggest that EACL presents notable analgesic and anti-inflammatory activities, which support its folkloric use for painful and inflammatory conditions.
Anti-inflammatory and analgesic activities of a standardized Orthosiphon stamineus methanol:water (50:50 vol/vol) leaf extract (SEOS) were evaluated in animal models. Oral administration of SEOS at doses of 500 and 1,000 mg/kg significantly reduced the hind paw edema in rats at 3 and 5 hours after carrageenan administration (P < .01 and P < .01; P < .01 and P < .05, respectively). SEOS (1,000 mg/kg, p.o.) also produced significant (P < .05) analgesic activity in both the acetic acid-induced writhing test and the formalin-induced licking test (late phase) in mice and rats, respectively. However, SEOS showed no effect on the tail flick and hot plate tests in mice. The results of the present study support the proposal that O. stamineus has anti-inflammatory and non-narcotic analgesic activities. These findings justify the traditional use of the plant for treating pain and inflammation.
The antinociceptive effect of the ethanolic extract of Melastoma malabathricum (MME) was investigated using acetic acid-induced abdominal writhing test and hot-plate test in mice. It was demonstrated that the extract (30-300 mg/kg, i.p.) strongly and dose-dependently inhibited the acetic acid-induced writhing with an ED(50) of 100 (78-160) mg/kg i.p. It also significantly increased the response latency period to thermal stimuli. Furthermore, the nonselective opioid receptor antagonist, naloxone blocked the antinociceptive effect of the extract in both tests, suggesting that M. malabathricum may act both at peripheral and central levels.
There appears to be a general tendency towards under-usage of analgesics not only in children but also in adults. The aim of this study was to describe the pattern of analgesic usage in adults and children admitted for major intra-abdominal surgery. All patients who had intra-abdominal surgery at University Science Malaysia Hospital (USM Hospital) from 1st January to 31st March 1995 were included in the study. Children were patients of 12 years and below and adults were patients above 12 years of age. Data including age, sex, weight, type of analgesics used, the number of patients who had analgesics ordered and administered post-operatively were obtained from the patients' medical record. A total of 48 children and 67 adults were studied. Narcotic analgesics were the most common analgesics ordered both in adults (95.5%) and in children (97%). Post-operative analgesics were ordered significantly more often for adults 67 (100%) than for children 33 (69%) (p < 0.0001). In adults, 70% of patients who had analgesics ordered post-operatively had their analgesics administered, but in children only 39.4% of patients had their analgesics administered (p < 0.001). The most common route of administration was intramuscular in both adults (95.5%) and children (88%). Analgesics were more likely to be administered in the intensive care units (100%) than in the surgical wards (60%) (p = 0.049). Elective or emergency surgery and the time of day when surgery was performed did not affect the frequency of analgesics ordered or administered. In summary, children in this hospital had less analgesics ordered and administered following intra-abdominal surgery compared to adults. The results of this study imply that increased attention should be given to relieve postoperative pain with analgesic drugs in children.
One hundred and eighty-three patients undergoing surgery were interviewed twenty-four hours following surgery to assess the quality of pain relief they received in the immediate postoperative period. Interviews were conducted using a standard questionnaire for all patients. They were asked to (1) rate the quality of pain relief they obtained on a Visual Pain Analogue Scale (VPAS-0 being no pain and 10 being the worst imaginable pain); (2) state whether they were happy and satisfied with the pain relief they received; (3) if dissatisfied, they were asked to give their reasons. 37.7% (69 patients) had moderate to severe pain--pain score greater than 6 on the VPAS. Most of these patients had undergone abdominal or major orthopaedic surgery. 32.7% (60 patients) were unhappy with their postoperative pain control. The main reasons for complaint from the patients were that analgesic injections were either not given promptly or were not given at all. The survey also highlighted the inadequate under-administration of narcotic injections in the postoperative period despite orders being written up. It showed there is an urgent need for setting up an Acute Pain Service for better postoperative pain control. An anaesthesiology based Acute Pain Service was started in October 1992.
The pattern of analgesic use, abuse and incidence of analgesic-associated nephropathy in 79 patients with chronic headache was studied. Sixty-eight of these patients had migraine. Most patients had consumed a combination of analgesics (81%) while 19% had taken single analgesics for their headache. Nonsteroidal anti-inflammatory drugs were the most commonly used analgesics (96.2%) followed by paracetamol (70.9%) and aspirin, phenacetin and caffeine compounds (5.1%). Mefenamic acid was the commonest nonsteroidal anti-inflammatory drug consumed (97.4%). Analgesic abuse which was defined as a minimum total of 1 kg of analgesics such as paracetamol or aspirin, phenacetin and caffeine compounds or 400 capsules/tablets of nonsteroidal anti-inflammatory drugs was noted in 65 patients. Nonsteroidal anti-inflammatory drugs were the most commonly abused analgesics (89.2%) followed by paracetamol (38.5%). Forty-five of the 65 analgesic abusers had an intravenous urogram or ultrasound performed and renal papillary necrosis was documented in one patient. Three (4.6%) of the analgesic abusers had mildly raised serum creatinine levels. Mild proteinuria of less than 1 gm/litre was present in 27.7% of abusers. In conclusion, although analgesic use and abuse is common in patients with chronic headache, the short term incidence of analgesic-associated nephropathy (2.2%) and renal impairment (4.6%) was low. Prolonged observations will be necessary to ascertain the safety of these drugs for long term use.