Loperamide,the “Poor Man’s Methadone”: Brief Review

Loperamide is widely available as an inexpensive, over-the-counter remedy commonly used for management of diarrhea. Although an opioid, at therapeutic doses it acts primarily on the gastrointestinal tissues; however, larger than recommended amounts facilitate central nervous system (CNS) penetration. Such high doses of loperamide have recently gained popularity among users of opioids to manage withdrawal symptomatology and, less frequently, to achieve psychoactive effects. Chronic loperamide use can result in development of tolerance and, upon abrupt cessation of use, withdrawal. With increasing prevalence of use, side-effects are noted, one particularly being life-threatening cardiac arrhythmias. Users are often not forthcoming and routine drug screens do not detect loperamide, so providers need to be alert to such practices in order to recognize intoxication, be able to screen for use, and facilitate entry into treatment.     

FOLFIRI方案联合西妥昔单抗治疗致反复严重腹泻1例

<正>FOLFIRI方案[伊立替康(irinotecan)、亚叶酸钙(calcium folinate)、氟尿嘧啶(fluorouracil)组成]联合西妥昔单抗(cetuximab)为KRAS野生型晚期结直肠癌患者首选治疗方案之一,对晚期大肠癌患者一线治疗有效率34.9%,中位疾病进展     

Loperamide improves anal sphincter function and continence after restorative proctocolectomy

The physiological and clinical effects of loperamide treatment versus placebo were investigated in a randomized, double-blind, crossover study in patients operated with restorative proctocolectomy. Sixteen patients operated with endoanal mucosectomy and a handsewn ileal pouch-anal anastomosis and 14 patients operated with abdominal proctocolectomy and stapling of the pouch to the top of the anal canal were studied. While loperamide treatment increased resting anal pressure in both groups of patients by approximately 20% (P<0.05), squeeze pressure was not affected. Loperamide did not affect pouch volume or contractility. Sensory thresholds and the recto/pouch-anal inhibitory reflex were not influenced by loperamide treatment. Clinical function was improved, with a reduced bowel frequency and an improved nighttime continence, with less soiling (P<0.05) as well as need to wear a protective pad.This investigation was supported by grants from the Swedish Medical Research Council (17X-03117), the University of Göteborg, Göteborgs Läkarsällskap, Assar Gabrielssons Fond, AB Skandias 100-årsfond and Ingabritt och Arne Lundbergs Forskningsfond.     

Loperamide Inhibits Replication of Severe Fever with Thrombocytopenia Syndrome Virus

Background: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne infectious disease caused by the SFTS virus (SFTSV). SFTS is mainly prevalent in East Asia. It has a mortality rate of up to 30%, and there is no approved treatment against the disease. In this study, we evaluated the effect of loperamide, an antidiarrheal and antihyperalgesic agent, on the propagation of SFTSV in a cell culture system. Methods: SFTSV-infected human cell lines were exposed to loperamide, and viral titers were evaluated. To clarify the mode of action of loperamide, several chemical compounds having shared targets with loperamide were used. Calcium imaging was also performed to understand whether loperamide treatment affected calcium influx. Results: Loperamide inhibited SFTSV propagation in several cell lines. It inhibited SFTSV in the post-entry step and restricted calcium influx into the cell. Furthermore, nifedipine, a calcium channel inhibitor, also blocked post-entry step of SFTSV infection. Conclusions: Loperamide inhibits SFTSV propagation mainly by restraining calcium influx into the cytoplasm. This indicates that loperamide, a Food and Drug Administration (FDA)-approved drug, has the potential for being used as a treatment option against SFTS.     

Stimulation of gastrointestinal motility by loperamide in dogs

The effects of loperamide on gastrointestinal motility were investigated in conscious fasted dogs chronically fitted with strain-gauge transducers on the antrum, the jejunum, and the colon. Oral administration of loperamide (0.1 mg/kg) induced, after a delay of 20–30 min, a long-lasting (8–12 hr) stimulation of gastrointestinal motility associated with a disorganization of the cyclic activity at the three levels investigated. These effects were reproduced by a subcutaneous administration at the same dose and were antagonized by previous intravenous administration of naloxone or a quaternary opiate antagonist. Intracolonic administration (0.1 mg/kg) stimulated, after a delay of 20–30 min, colonic motility only. Intracerebroventricular loperamide (1 g/kg) induced a long-lasting (15–20 hr) inhibition of the gastric motility and a short (2-hr) disorganization of the jejunal motor profile. These data show that oral loperamide stimulates gastrointestinal motility in dogs and involves peripheral opiate receptors.     

Racecadotril versus loperamide: antidiarrheal research revisited

Racecadotril is an enkephalinase inhibitor, presented as a purely antisecretory agent with advantages over the opiate-receptor agonist loperamide in the treatment of diarrhea. A critical review of the literature and the models used was performed. Although pretreatment with high doses of racecadotril reduced cholera toxin-induced secretion and although clinical efficacy was demonstrated in young infants—a population characterized by 10-fold higher plasma enkephalin concentrations compared with adults, the analysis calls into question the peripheral antisecretory selectivity and relative clinical efficacy. Conversely, loperamide can be proposed as an antisecretory agent at therapeutic concentrations. Its efficacy is well established in acute and chronic diarrhea. Current experimental and clinical comparative studies of both drugs have problems with regard to the selection of the doses, the validity of models, and/or the trial design. The conclusion is that more research is needed before reliable conclusions can be drawn on the place of racecadotril in diarrhea treatment.     

Effects of the prodrug loperamide oxide,loperamide, and placebo on jejunal motor activity

This crossover, double-blind study investigated the effects of single oral doses of the prodrug loperamide oxide, which is reduced gradually to loperamide in the intestine, and loperamide on jejunal motor activity in 12 fasting healthy men. Five minutes after a phase III of the migrating motor complex (MMC), 2 mg loperamide oxide, 4 mg loperamide oxide, 4 mg loperamide, or placebo were administered. Thereafter, motor activity 10–30 cm aborad the ligament of Treitz was recorded with five catheter orifices at 3-cm intervals over 4 hr. Number of contractions and area under curve increased significantly with 4 mg loperamide and 4 mg loperamide oxide, the increases with loperamide oxide occurring more gradually. Placebo and 2 mg loperamide oxide had no discernible effects. With both 4 mg loperamide and 4 mg loperamide oxide, phase I of the MMC was slightly prolonged and phase II and the time from drug administration to the onset of the first phase III slightly shortened. The percentage of aborally propagated contractions in phase II increased with all active treatments, whereas the occurrence of phases III was not altered.Presented in poster form at the European Digestive Disease Week, Vienna, Austria, June 5–9, 1990Supported by Janssen Pharmaceutica, Beerse, Belgium.     

Interference of antimycotics and other drugs with methohexital hypnosis in rats

Compounds of various pharmacological and chemical classes were studied for their interaction with methohexital hypnosis. Rats were treated daily for 5 days with an oral dose of a test compound or solvent. On days 1, 5, and 8 methohexital was injected intraperitoneally and the duration of hypnosis was measured. Three types of interaction with methohexital hypnosis were observed. Acute prolongation of hypnosis on day 1 was the most marked effect of fluconazole (median effective dose, ED₅₀: 8.66 mg/kg), but this occurred also with phenobarbital (ED₅₀: 26.4 mg/kg) and diphenylhydantion (ED₅₀: ～ 160 mg/kg). Tolerance to prolongation, i.e., a decrease of the hypnosis time by more than 50% from day 1 to day 5, was most marked with phenobarbital (ED₅₀: 12.6 mg/kg) and diphenylhydantion (ED₅₀: 113 mg/kg) but was also found with fluconazole (ED₅₀: 22.6 mg/kg). Shortened hypnosis times on day 8 occurred with phenobarbital (ED₅₀: ～ 40.0 mg/kg) and diphenylhydantoin (ED₅₀: ～ 160 mg/kg). The antimycotic itraconazole, the antidiarrheal loperamide, the thymosthenic agent ritanserin, and the antiallergics astemizole and levocabastine were devoid of interactions with methohexital. When compared with the basic activity of the tested compounds in rats, interference with methohexital hypnosis was most pronounced with phenobarbital (ratio 3.13) followed by fluconazole (ratio: 3.28) and diphenylhydantoin (ratio: 5.07).