Split-thickness skin grafting in the management of cutaneous sequelae of intramuscular pentazocine injections: a novel approach.

INTRODUCTION: Pentazocine, a synthetic opioid with partial agonist and antagonist activity administered by parenteral injection, was used clinically in the 1970s. Dermatologic complications at injection sites were reported soon after its introduction. These complications are thought to be underreported. Many well-documented cases describe the development of fibrosis and calcinosis at the site of parenteral pentazocine injections, but few reports document management or successful treatment of the long-term sequelae of these manifestations. CASE REPORT: The successful use of STSG for the treatment of chronic nonhealing ulcers secondary to pentazocine-induced cutaneous fibrosis in a 78-year-old male is presented. In the early 1970s, he was started on 3-times-daily intramuscular pentazocine injections to treat pain secondary to ulcerative colitis. He injected himself in the proximal thighs and buttocks for a period of approximately 10 years. He gradually developed severe soft tissue calcifications of both buttocks and anterior thighs. In the mid-to-late 1980s, the pentazocine injections were discontinued. The diffuse sclerosis and disfiguring fibrosis remained. CONCLUSIONS: This case underscores the lasting effects of pentazocine-induced cutaneous sclerosis and fibrosis, with cutaneous complications manifesting in this patient even decades after use. It also highlights the novel use of STSG as a treatment strategy for these cutaneous complications.

Boerhaave's syndrome after pentazocine-induced vomiting in a 21-year-old male with asthma: a case report.

Boerhaave's syndrome is an uncommon syndrome characterized by spontaneous rupture of the oesophagus with a high mortality rate. While excessive alcohol intake and binge-eating are the classic precipitants of this syndrome, medication-induced vomiting causing Booerhave's is quite uncommon. Traditionally managed operatively, conservative management is being increasingly reported in selected cases. We report the case of 21-year-old male with who developed sudden onset chest pain and dyspnoea after pentazocine induced vomiting. He was referred after lack of response to initial treatment for acute severe asthma. A chest CT scan showed pneumomediastinum, subcutaneous emphysema and oesophageal tear. He was managed conservatively with oxygen therapy, nil per mouth and antibiotics with improvement of symptoms and discharge after 8 days.

Pentazocine, a Kappa-Opioid Agonist, Is Better Than Diclofenac for Analgesia in Acute Pancreatitis: A Randomized Controlled Trial.

OBJECTIVES: The ideal analgesic is not known for patients with acute pancreatitis (AP). Concerns have been raised about serious adverse effects of opioid analgesics increasing the severity of AP. We hypothesized that nonsteroidal anti-inflammatory drugs might be better analgesics because of their anti-inflammatory effect. Our objective was to compare pentazocine, an opioid, and diclofenac, a nonsteroidal anti-inflammatory drug, for adequate analgesia in patients with AP. METHODS: In a double-blind randomized controlled trial, patients with AP were randomized to either intravenous diclofenac 75 mg or pentazocine 30 mg. Fentanyl was given as a rescue analgesic through a patient-controlled analgesia pump. Primary outcome was pain relief measured objectively by the dose of fentanyl required as the rescue analgesic, pain-free period, and numbers of effective and ineffective demands of fentanyl. Secondary outcome was adverse events. RESULTS: Fifty patients were randomized, 24 to the pentazocine group and 26 to the diclofenac group. Baseline characteristics were comparable between the groups. Pentazocine was found to be better than diclofenac in terms of significantly lower dose of the rescue analgesic (fentanyl) required (126 µg (interquartile range (IQR) 65-218 µg) vs 225.5 µg (IQR 133-427 µg); P = 0.028) and longer pain-free period (31.1 ± 8.2 vs 27.9 ± 6.6 hours, P = 0.047). The number of effective and ineffective demands was lower in the pentazocine group compared with the diclofenac group (11.5 (IQR 8-15) vs 16 (IQR 13-20), P = 0.098) although not statistically significant. Adverse events were similar between the groups. CONCLUSIONS: Pentazocine, a kappa-opioid receptor agonist, was significantly better than diclofenac for pain relief in AP (Trial registration number: CTRI/2016/09/007326).

Off-label use of pentazocine and the associated adverse events among pediatric surgical patients in a tertiary hospital in Northern Nigeria: a retrospective chart review.

Background and aims: Pentazocine remains a widely used opioid pre-anesthetic medication and post-operative analgesic in low- and middle-income countries despite concerns. We assessed the adverse events (AEs) associated with off-label use of pentazocine in pediatric surgical patients and determined the possible risk factors associated with slow respiratory AEs.Method: Children ≤18 years old were administered pentazocine IM/IV as a pre-anesthetic medication or post-operative analgesic. Pertinent data including total daily dose and duration of use of pentazocine and its associated AEs were obtained from patients' case files. Risk factors associated with slow respiratory AEs were determined using logistic regression analyses.Results: One hundred and fifty-nine patients were included with a median age of 2 years; they were mainly males (52.8%). Pentazocine was administered off-label to all patients for post-operative pain management (96.2%) or pre-anesthetic medication (3.8%). All patients experienced at least one AE with most experiencing 2-7 AEs. Rapid breathing (120; 18.7%), followed by fast pulse (101; 15.7%) and sleepiness/sedation/drowsiness (81; 12.6%) were the most common AEs. None of the demographics and clinical variables significantly predicted the risk of slow respiratory AEs.Conclusion: Off-label use of pentazocine is common and associated with multiple AEs. Care is needed as no predictors of slow respiratory AEs were observed.

Clinical and socio-demographic determinants of pentazocine misuse among patients with sickle cell disease, Benin City, Nigeria: a case-control study.

INTRODUCTION: Opioids are a mainstay in sickle cell disease (SCD) pain care. Opioids are known to cause physical and/or psychological dependence. Increasingly, a significant number of Nigerian SCD patients ("Pentaholics") are observed to abuse pentazocine. This trend is associated with new patterns of medical complications. This study aimed to describe the local spectrum of pentazocine abuse complications and identify possible clinical and socio-demographic determinants. METHODS: We conducted a case control (age matched) study involving 50 booked SCD patients (25 cases and 25 controls) receiving care at the University of Benin Teaching Hospital, Benin City, Nigeria. Relevant clinical and socio-demographic details were collected and analyzed. Associations of categorical variables were tested using chi square or Fishers exact test. RESULTS: The median participants' age and duration of pentazocine abuse/self-use were 32 and 7 years respectively. Pentazocine injections were gotten from local pharmacies and patent medicine stores without any need for physician prescriptions (84% of cases). The buttocks, the thigh and the upper arm/deltoid were the commonest site of injection. Major complications observed were chronic ulcers on the thigh, deep wounds with abscess, healed scar at multiple sites, lower limb swelling and venous thrombosis. Working in healthcare fields/hospitals (Doctor, Nurses, Pharmacists) was significantly associated with pentazocine abuse. CONCLUSION: Health personnel or hospital workers living with SCD are more likely to abuse pentazocine. There is need for prompt triage and optimal control of acute sickle pain, institutional protocols for pain management and strict regulations on supply of prescription drugs such as pentazocine.

Thiamylal Plus Pentazocine Shows Similar Efficacy as Ketamine Plus Midazolam for Painful Procedures in Children With Leukemia.

This retrospective study compared the use of thiamylal plus pentazocine (TP) to ketamine plus midazolam (KM) in children with leukemia who were undergoing bone marrow aspiration and/or intrathecal chemotherapy. A total of 268 procedures in 35 children with leukemia were retrospectively analyzed for efficacy and adverse events. All procedures were successfully completed without severe adverse events. TP induced significantly faster sedation. The incidents of desaturation were significantly greater in the TP group, but were transient and recovered by oxygen supplementation alone. Therefore, TP can be a useful combination with a similar efficacy as KM for painful procedures in children.

Prophylactic Pentazocine Reduces the Incidence of Pruritus After Cesarean Delivery Under Spinal Anesthesia With Opioids: A Prospective Randomized Clinical Trial.

BACKGROUND: The incidence of pruritus after cesarean delivery under spinal anesthesia with opioids is high, ranging from 50% to 100%. Pruritus is difficult to prevent; however, pentazocine has been shown to be an effective treatment. Despite this, the prophylactic effect of pentazocine on pruritus has not been defined. This randomized double-blind trial aimed to evaluate the effect of intraoperative IV pentazocine on the incidence of opioid-induced pruritus within the first 24 hours after administration of neuraxial opioids. METHODS: We obtained institutional review board approval and written informed consent from the 122 patients (American Society of Anesthesiologists [ASA] physical status II; aged 20-40 years) scheduled for elective cesarean delivery who were included in this study. Spinal anesthesia was performed with 10 mg of 0.5% hyperbaric bupivacaine, 10 µg of fentanyl, and 100 µg of morphine. After delivery of the baby and placenta, the parturient women were randomized to intravenously receive 15 mg (1 mL) of pentazocine or 1 mL of saline. All women received postoperative analgesia with the epidural infusion of 0.15% levobupivacaine. The presence of pruritus within the first 24 hours after intrathecal administration of opioids was recorded, and severity of itch, numerical rating scale (NRS) for pain, and adverse effects were also recorded at the time of the arrival on the ward, as well as 3, 6, 12, and 24 hours after the intrathecal administration of opioids. RESULTS: A total of 119 women completed the study. IV pentazocine reduced the overall incidence of pruritus within the first 24 hours compared to IV saline, with an estimated relative risk of 69% (95% confidence interval [CI], 52%, 90%; P = .007). IV pentazocine also reduced the severity of pruritus. The incidence of nausea and vomiting was not significantly different. There were no significant differences in postoperative NRS scores. CONCLUSIONS: A single 15-mg dose of IV pentazocine after delivery can reduce both the incidence and severity of pruritus in women who have received subarachnoid opioids during cesarean delivery.

Sigma-1 Receptor Agonism Promotes Mechanical Allodynia After Priming the Nociceptive System with Capsaicin.

Sigma-1 receptor antagonists promote antinociception in several models of pain, but the effects of sigma-1 agonists on nociception (particularly when the nociceptive system is primed) are not so well characterized; therefore we evaluated the effects of sigma-1 agonists on pain under different experimental conditions. The systemic administration of the selective sigma-1 agonists (+)-pentazocine and PRE-084, as well as the nonselective sigma-1 agonist carbetapentane (used clinically as an antitussive drug), did not alter sensitivity to mechanical stimulation under baseline conditions. However, they greatly promoted secondary mechanical allodynia after priming the nociceptive system with capsaicin. These effects of sigma-1 agonists were consistent in terms potency with the affinities of these drugs for sigma-1 receptors, were reversed by sigma-1 antagonists, and were not observed in sigma-1 knockout mice, indicating that they are sigma-1-mediated. Repeated systemic treatment with PRE-084 induced proallodynic effects even 24 h after treatment completion, but only after the nociceptive system was primed. However, neither the presence of this drug in the organism nor changes in sigma-1 receptor expression in areas involved in pain processing explains its long-term effects, suggesting that sustained sigma-1 agonism induces plastic changes in the nociceptive system that promote nociception.

Mechanisms of pentazocine-induced ventilatory depression and antinociception in anesthetized rats.

This study was performed to clarify mechanisms underlying pentazocine-induced ventilatory depression and antinociception. Spontaneous ventilation and hind leg withdrawal response against nociceptive thermal stimulation were simultaneously recorded in anesthetized rats. Pentazocine decreased minute volume resulting from depression of the ventilatory rate and tracheal airflow, and prolonged the latency of withdrawal response. Pre-treatment of ß-funaltorexamine, but not nor-binaltorphimine, significantly attenuated pentazocine-induced ventilatory depression, while either antagonist weakened its analgesic potency. Comparing with effects of fentanyl and U50488, the present results suggest that ventilatory depression induced by pentazocine is mediated by mainly µ receptors and analgesia by both µ and κ receptors.

A randomized controlled trial comparing Pentazocine and Chamomilla recutita for labor pain relief.

BACKGROUND: Traditional birth attendants in Pakistan sometimes use a homeopathic remedy, Chamomilla for labor pain relief. Our study compares this homeopathic remedy for pain relief in labor with a commonly used parenteral analgesic in a hospital setting. No systematic study has been conducted previously to study the effect of chamomile, which may be affordable and available in community settings. METHODS: A double blind randomized controlled trial was carried out at Islamic International Medical College Trust. Ninety-nine normal pregnant women were randomly assigned into three groups. Each group received one of the three trial drugs; Chamomile, Pentazocine or placebo. The efficacy of labor analgesia was assessed by using Visual Analogue Scale (VAS) for pain intensity. Indicators of maternal and child health were recorded as were adverse effects of the drugs. RESULTS: Mean pain scores in the three groups were calculated and compared. The difference in mean VAS scores in Pentazocine and Chamomilla recutita group as compared with placebo was not statistically significant. No significant adverse effects were noticed in any group except slight headache and dizziness in three parturients in Pentazocine group. CONCLUSION: Neither Pentazocine, or Chamomilla recutita offer substantial analgesia during labor.

Pentazocine-induced contractures: Dilemma in management.

Pentazocine is a commonly used synthetic opioid analgesic for moderate to severe pain secondary to various conditions. Complications of parenteral opioid abuse including localized ulcerations, abscess, indurations, and sclerosis are well-documented. We present a rare case of drug abuse due to pentazocine (Fortwin) in a 32-year-old female, who had severe myogenic contractures of her knee joints.

κ Agonists as a novel therapy for menopausal hot flashes.

OBJECTIVE: The etiology of postmenopausal hot flashes is poorly understood, making it difficult to develop and target ideal therapies. A network of hypothalamic estrogen-sensitive neurons producing kisspeptin, neurokinin B and dynorphin-called KNDy neurons-are located adjacent to the thermoregulatory center. KNDy neurons regulate pulsatile secretion of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH). Dynorphin may inhibit this system by binding κ opioid receptors within the vicinity of KNDy neurons. We hypothesize that hot flashes are reduced by KNDy neuron manipulation. METHODS: A double-blind, cross-over, placebo-controlled pilot study evaluated the effects of a κ agonist. Hot flash frequency was the primary outcome. Twelve healthy postmenopausal women with moderate to severe hot flashes (aged 48-60 y) were randomized. Eight women with sufficient baseline hot flashes for statistical analysis completed all three interventions: placebo, standard-dose pentazocine/naloxone (50/0.5 mg), or low-dose pentazocine/naloxone (25/0.25 mg). In an inpatient research setting, each participant received the three interventions, in randomized order, on three separate days. On each day, an intravenous catheter was inserted for LH blood sampling, and skin conductance and Holter monitors were placed. Subjective hot flash frequency and severity were recorded. RESULTS: The mean (SEM) hot flash frequency 2 to 7 hours after therapy initiation was lower than that for placebo (standard-dose κ agonist, 4.75 [0.67] hot flashes per 5 h; low-dose κ agonist, 4.50 [0.57] hot flashes per 5 h; placebo, 5.94 [0.78] hot flashes per 5 h; P = 0.025). Hot flash intensity did not vary between interventions. LH pulsatility mirrored objective hot flashes in some--but not all--women. CONCLUSIONS: This pilot study suggests that κ agonists may affect menopausal vasomotor symptoms.

Parenteral pentazocine and diabetes mellitus: a double whammy for cutaneous complication.

Pentazocine, a non-narcotic analgesic, though has no addictive potential but abused frequently via parenteral route for its psychological dependence. It causes local sclerosis resulting in non-healing ulcer at injection sites. Diabetes mellitus suppress host immunity, making them vulnerable to various bacterial skin and soft tissue infection among which mkethicillin resistant staphylococcus aureus (MRSA) infection are predominant. We report a case, a 50-year-old shopkeeper who used to inject pentazocine primarily as analgesic, later became addicted to it. Blindly injecting the drug in any approachable soft tissue resulted in woody induration of local skin with multiple ulcers in his both arms. He later developed type 2 Diabetes mellitus which made the scenario even worser.

Administration of additional analgesics can decrease the incidence of paradoxical reactions in patients under benzodiazepine-induced sedation during endoscopic transpapillary procedures: prospective randomized controlled trial.

AIM: The aim of the present study was to evaluate the efficacy and safety of giving pentazocine as an analgesic with benzodiazepine during endoscopic retrograde cholangiopancreatography (ERCP). METHODS: The paradoxical reactions (PR) incidence was evaluated as an indicator of usefulness. Transcutaneous arterial carbon dioxide tension (PtcCO(2) ) was evaluated as an indicator of safety. A total of 160 patients were enrolled. Subjects were randomly divided into two groups; group 1 sedated with midazolam only and group 2 sedated both with midazolam and pentazocine (7.5 mg). RESULTS: The initial dosage introduced sedation before procedure was significantly higher in group 1. The occurrence rate of PR's in group 1 was significantly higher compared to that in group 2 (P = 0.0108). Although maximum PtcCO(2) observed during sedation did not differ between the two groups (48.7 ± 7.2, 50.3 ± 7.6 mmHg, respectively),maximum PtcCO(2) during the first 15 min after the start of sedation was significantly higher in group 2 than in group 1 (P = 0.0294). In multivariate analysis, procedure duration (odds ratio [OR] = 1.048) and midazolam dose (OR = 1.221) were predictive factors for PR. CONCLUSION: The administration of pentazocine is significantly reduced the incidence of PR's in patients under midazolam induced sedation during ERCP.