Ulnar neuropathy (UN) is the second most common entrapment neuropathy, typically resulting from trauma, fractures, compression, dislocations, repetitive elbow movements, or congenital malformations secondary to previous injuries. However, it may also arise as a complication of substance abuse. We report the case of a 45-year-old male with bilateral ulnar neuropathy secondary to 22 years of intravenous pentazocine (Sosegon) abuse, highlighting repeated local tissue injury and fibrosis as potential pathogenic factors. The patient presented with progressive swelling, numbness, and pain in both upper extremities, along with a bilateral flexion contracture of the left fourth and fifth digits. Nerve conduction studies (NCS) revealed severe left ulnar neuropathy at the elbow distal to the branch of the flexor carpi ulnaris, and moderate-to-severe right ulnar neuropathy at the elbow proximal to the same branch. Needle electromyography (EMG) demonstrated significant denervation in muscles innervated by the ulnar nerve. After preoperative evaluation, the patient underwent successful ulnar nerve transposition followed by physiotherapy, resulting in symptomatic improvement at six-month follow-up. This case highlights chronic pentazocine abuse as a rare but significant cause of bilateral ulnar neuropathy, likely due to repeated local trauma and fibrosis. Early recognition and a multidisciplinary management strategy involving neurosurgery, addiction medicine, and physiotherapy to address both the neurological sequelae and the underlying substance abuse are essential to optimizing long-term functional and clinical outcomes.

Opioid use disorder (OUD) is an emerging public-health challenge in Nigeria, driven largely by non-medical use of tramadol and codeine and compounded by limited access to evidence-based care. This narrative review synthesises evidence on the epidemiology, patterns, harms and treatment gaps for OUD in Nigeria and identifies priorities for policy and research. We searched PubMed/MEDLINE, Embase, PsycINFO, the Cochrane Library, African Journals Online, Google Scholar and grey literature from 2005 to 2024 for Nigerian data on non-medical opioid use, clinical harms, opioid agonist therapy (OAT) services, barriers and community supports. Findings were thematically synthesised using Braun and Clarke's framework, with quality appraisal using Joanna Briggs Institute tools and the SANRA scale. Thirty studies were included. The 2019 national drug use survey estimated past-year opioid use at 4.7% (approximately 4.6 million people), with institution-based surveys reporting high lifetime misuse among undergraduates. Reported harms included overdose, seizures, psychiatric comorbidity and injectable pentazocine dependence with severe soft-tissue infections. OAT availability remains highly centralised, with limited community recovery infrastructure. Nigeria's OUD burden is substantial but unevenly characterised, highlighting the need to decentralise OAT, integrate addiction training, strengthen surveillance and expand community supports.

Retinopathy of prematurity (ROP) remains a leading cause of childhood blindness. Although current therapies effectively suppress pathological neovascularization, many patients continue to exhibit persistent visual dysfunction despite regression of active disease, highlighting an unmet need for neuroprotective interventions. Sigma 1 receptor (Sig1R), an endoplasmic reticulum-mitochondrial chaperone and regulator of cellular stress responses, has emerged as a promising therapeutic target in neurodegenerative and retinal diseases. Here, we investigated whether Sig1R activation confers sustained neuroprotection following neonatal ischemic retinal injury. Wild-type and Sig1R knockout mice were subjected to oxygen-induced retinopathy (OIR) and treated systemically with the high-affinity Sig1R agonist (+)-pentazocine [(+)-PTZ]. Retinal structure and visual function were assessed longitudinally through 20 weeks of age using visual acuity, contrast sensitivity, electroretinography (ERG), pattern ERG (PERG), spectral-domain optical coherence tomography (SD-OCT), and histological analyses. Chronic Sig1R activation significantly preserved visual acuity, contrast sensitivity, rod- and ganglion cell-mediated retinal function, retinal ganglion cell survival, and inner retinal architecture in OIR mice. These protective effects were abolished in Sig1R-deficient mice, demonstrating a requirement for Sig1R in mediating neuroprotection. Mechanistically, Sig1R activation reduced apoptotic signaling, attenuated oxidative and nitrosative stress, improved mitochondrial respiratory function, and enhanced endogenous antioxidant pathways. Collectively, these findings demonstrate that Sig1R activation provides durable, receptor-dependent neuroprotection following neonatal ischemic retinal injury by coordinating redox, mitochondrial, and cell-survival pathways. These results identify Sig1R as a promising therapeutic target for preserving retinal neuronal integrity and long-term visual function in retinopathy of prematurity.

Pain is often the presenting symptom of acute pancreatitis (AP) and has a prognostic significance, with poorly treated pain affecting patient outcomes. Despite this, there are currently no international recommendations for pain management in patients admitted with AP. This current guideline was developed following the United European Gastroenterology framework for the development of high-quality clinical guidelines. Nine working groups were formed to develop statements on pain management in AP from admission to discharge. After systematic literature reviews, the evidence was evaluated according to the Grading of Recommendations Assessment, Development, and Evaluation methodology, as appropriate. Statements and comments were developed by the working groups and voted using three rounds of Delphi method. The guidelines concluded that acute postoperative pain management guidelines are applicable for treating acute pain due to AP. The numerical rating scale is preferred for pain assessment because of better compliance. Opioids currently form the cornerstone of severe pain management. Potent opioids such as buprenorphine and pentazocine provide superior pain relief over non-opioid medications and decrease the need for rescue analgesia. Current evidence does not consistently demonstrate harm from opioids in AP. In patients with severe pain, safety concerns should not delay the timely use of opioids to ensure adequate pain management. Specific recommendations concerning the use of epidural analgesia, acupuncture and management of pain in the paediatric population and during pregnancy are provided based on evidence and expert opinions. Finally, the unmet needs for future research were discussed and proposed.

The sigma-1 receptor (S1R) is an endoplasmic reticulum transmembrane protein implicated in a wide range of physiological and pathological processes, including neurodegeneration, cancer, and pain modulation. Although X-ray crystallography has revealed S1R as a trimeric assembly with a distinctive triangular architecture, the dynamic behavior of this oligomeric state and its modulation by ligands and membrane composition remain poorly understood. In particular, agonists and antagonists have been experimentally proved to differentially regulate S1R oligomerization, although the underlying molecular mechanisms are still obscure. Here, we present one of the first atomistic molecular dynamics studies of the human S1R trimer; the system is embedded in a cholesterol-containing lipid membrane, which provides a more physiologically relevant environment. Using a total of 12 μs of simulation time, we investigate the impact of membrane composition, with a specific focus on cholesterol, as well as the conformational response of S1R to pharmacologically distinct ligands: the agonist (+)-pentazocine and the antagonist haloperidol. Our simulations reveal how ligands can alter S1R interprotomer interaction through a mechanism involving the β6 strand of the protein and in particular W136, data that correlate with experimentally observed differences in S1R oligomerization. These findings provide new molecular-level insights into S1R regulation and establish a framework for rationalizing the distinct functional outcomes induced by agonists and antagonists.

Despite the clinical importance of combining acetaminophen and opioids in multimodal analgesia, their compatibility has not been determined. This study aimed to investigate the stability and feasibility of mixing acetaminophen injection with six commonly used opioid drugs. Acetaminophen injection was mixed with each of the six opioid drugs at room temperature (25°C). Changes in appearance, pH, and acetaminophen concentrations were monitored at different time intervals to evaluate compatibility. Compatibility was defined as no visible changes, pH variation <1.0, and acetaminophen concentration ≥90% of baseline. The results indicated that acetaminophen injection, when mixed with six commonly used opioid drugs, remained stable for up to 48 h at room temperature. No significant changes were observed in the appearance of the mixtures, which remained clear and free of precipitation. The pH of the mixtures fluctuated by less than 1.0 unit, and the acetaminophen concentration remained above 90% of the baseline value, with a variation of less than 10%. Acetaminophen injection was compatible with morphine, sufentanil, hydromorphone, pentazocine, butorphanol, and nalbuphine for at least 48 h at 25°C, supporting their co-use in patient-controlled intravenous analgesia. Further studies should define pharmacokinetics and adverse effects of these combinations.

No information is available on the use of pentazocine during breastfeeding. Maternal use of oral narcotics during breastfeeding can cause infant drowsiness, central nervous system depression and even death. Newborn infants seem to be particularly sensitive to the effects of even small dosages of narcotic analgesics. Once the mother's milk comes in, it is best to provide pain control with a nonnarcotic analgesic and limit maternal intake of pentazocine to a few days at a low dosage with close infant monitoring. If the baby shows signs of increased sleepiness (more than usual), difficulty breastfeeding, breathing difficulties, or limpness, a physician should be contacted immediately. Other agents are preferred over pentazocine during breastfeeding.[1]