Contribution of nociceptin/orphanin FQ receptors to the anti-nociceptive and hypothermic effects of dipyrone

Endocannabinoid and N-acylethanolamide levels in rat brain and spinal cord following systemic dipyrone and paracetamol administration

The cannabinoid system has been suspected to play a role in the mechanisms of action of dipyrone and paracetamol. Our purpose was to measure the local endocannabinoid and N-acylethanolamide levels in the brain and spinal cord of rats following dipyrone and paracetamol administration. Nociception was assessed 1, 5, and 12 h following drug injections in Wistar rats, using tail-flick and hot-plate tests. The antinociceptive effects of dipyrone (150, 300, and 600 mg/kg, i.p.) and paracetamol (30, 100, and 300 mg/kg, i.p.) were observed. After administration of the highest doses of dipyrone and paracetamol, endocannabinoid (N-arachidonoylethanolamide (AEA), 2-arachidonoylglycerol (2-AG)) and N-acylethanolamide (palmitoylethanolamide (PEA), oleoylethanolamide (OEA)) levels were measured in the periaqueductal gray (PAG), rostral ventromedial medulla (RVM), and spinal cords of rats using tandem mass spectrometry with liquid chromatography. Increased 2-AG levels were observed in the PAG and the RVM 12 h after paracetamol injection; dipyrone exerted no action on 2-AG levels. Analgesic administrations led to a reduction in AEA levels in the RVM and spinal cord; similar decreases in PEA and OEA levels were observed in the RVM and the spinal cord. Dipyrone and paracetamol administrations appear to exert complicated effects on endocannabinoid and N-acylethanolamide levels in rats.

Dipyrone is the preferred nonopioid analgesic for the treatment of acute and chronic pain. A survey of clinical practice in German-speaking countries

PURPOSE

Nonopioid analgesics are frequently used for the treatment of acute and chronic pain. Dipyrone is an alternative to NSAIDs and paracetamol, however, data on the frequency of its usage by anaesthesiologists in the perioperative and chronic pain setting are lacking and its adverse reactions are a matter of debate.

METHODS

The link to a questionnaire on the use of nonopioid analgesics (NSAIDs, COX-2 inhibitors, paracetamol, dipyrone) and the safety of dipyrone in the perioperative and chronic pain setting was mailed to anaesthesiologists and pain physicians.

RESULTS

A total of 2237 responses were analysed. About 97.4% of the respondents used nonopioid analgesics for the treatment of acute pain, with 93.8% administering dipyrone, 54.0% NSAIDs, 41.8% COX-2 inhibitors and 49.2% paracetamol. Nonopioid analgesics were administered preoperatively by 22.3%, intraoperatively by 86.1% and postoperatively by 73.0% of the respondents. For chronic pain management, 76.7% of the respondents prescribed oral dipyrone in combination with other nonopioid analgesics; 19.9% used dipyrone as sole nonopioid, whereas 2.9% denied its use. Cases of dipyrone-associated agranulocytosis were observed by 3.5% of the respondents of the acute and 1.5% of the chronic pain questionnaire, respectively. The majority of respondents (acute pain: 73.0%, chronic pain 59.3%) performed no blood cell counts to monitor dipyrone therapy. Patients were rarely informed about possible adverse drug reactions.

CONCLUSIONS

Dipyrone is the preferred nonopioid analgesic in the perioperative and chronic pain setting. Although cases of agranulocytosis occur, benefits apparently outweigh the risks according to anaesthesiologists. Measures like patient information may improve safety.

SIGNIFICANCE

A survey of anaesthesiologist in German-speaking countries revealed dipyrone as preferred nonopioid analgesic for the treatment of acute and chronic pain. Benefits seem to outweigh the risks, specifically the risk of agranulocytosis. Information of medical staff and patients on adverse drug reactions and symptoms of agranulocytosis should be implemented.

Endogenous Opiates and Behavior: 2015

This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.

Metamizole/dipyrone for the relief of cancer pain: A systematic review and evidence-based recommendations for clinical practice

BACKGROUND

Dipyrone (metamizole) is one of the most widely used non-opioid analgesics for the treatment of cancer pain.

AIM

Because evidence-based recommendations are not yet available, a systematic review was conducted for the German Guideline Program in Oncology to provide recommendations for the use of dipyrone in cancer pain.

DESIGN

First, a systematic review for clinical trials assessing dipyrone in adult patients with cancer pain was conducted. Endpoints were pain intensity, opioid-sparing effects, safety, and quality of life.

DATA SOURCES

The search was performed in MedLine, Embase (via Ovid), and the Cochrane Library (1948-2013) and additional hand search was conducted. Finally, recommendations were developed and agreed in a formal structured consensus process by 53 representatives of scientific medical societies and 49 experts.

RESULTS

Of 177 retrieved studies, 4 could be included (3 randomized controlled trials and 1 cohort study, n = 252 patients): dipyrone significantly decreased pain intensity compared to placebo, even if low doses (1.5-2 g/day) were used. Higher doses (3 × 2 g/day) were more effective than low doses (3 × 1 g/day), but equally effective as 60 mg oral morphine/day. Pain reduction of dipyrone and non-steroidal anti-inflammatory drugs did not differ significantly. Compared to placebo, non-steroidal anti-inflammatory drugs, and morphine, the incidence of adverse effects was not increased.

CONCLUSION

Dipyrone can be recommended for the treatment of cancer pain as an alternative to other non-opioids either alone or in combination with opioids. It can be preferred over non-steroidal anti-inflammatory drugs due to the presumably favorable side effect profile in long-term use, but comparative studies are not available for long-term use.