piperidines and Addison-Disease

Loperamide is a peripheral opiate agonist able to inhibit ACTH secretion. In this work, the interactions between loperamide and two ACTH secretagogues, lysine vasopressin (LVP) and corticotropin-releasing hormone (CRH), were investigated in patients with Addison's disease. After loperamide (16 mg orally) or placebo administration, 5 patients received LVP (0.06 IU/kg i.v. over 1 h) and 6 patients received oCRH (1 micrograms/kg i.v. as bolus). In all patients loperamide induced a significant fall in plasma ACTH levels. LVP increased ACTH levels after both loperamide (from 48 +/- 17.3 to a peak of 95 +/- 21 pmol/l) and placebo (from 231 +/- 59.5 to 365 +/- 86.6 pmol/l): the interaction between treatments and time was not significant. CRH caused a rise in plasma ACTH after both loperamide (from 30 +/- 16.6 to a peak of 108 +/- 31 pmol/l) and placebo (from 98.5 +/- 47 to 211 +/- 61.7 pmol/l): the interaction between treatments and time was significant, and the first phase of CRH-induced ACTH secretion was significantly lower after loperamide. These data demonstrate that loperamide differently modifies the stimulatory action of LVP and CRH on ACTH secretion: namely, LVP and loperamide act in an additive manner, while CRH and loperamide interact in a non additive way. Although these findings might be explained by the involvement of different intracellular ACTH-secreting mechanisms, an influence of loperamide on some suprapituitary factors modulating the ACTH response is suggested.

Topics: Addison Disease; Adrenocorticotropic Hormone; Adult; Aged; Corticotropin-Releasing Hormone; Double-Blind Method; Drug Interactions; Female; Humans; Loperamide; Lypressin; Male; Middle Aged; Piperidines; Random Allocation

The effects of loperamide, an opiate analogue of the piperidine class on pituitary hormone secretion were evaluated in eight patients with Addison's disease. In all patients loperamide administration (16 mg orally) induced a marked fall in plasma ACTH levels (P less than 0.01), without affecting GH, PRL and LH levels. Plasma ACTH concentration fell significantly from 854 +/- 167 pg/ml (mean +/- SEM) to 460 +/- 123 pg/ml at 60 min (P less than 0.01). The inhibition persisted throughout the whole test period, the nadir being reached at 300 min. Low dose naloxone infusion 180 min after loperamide administration caused plasma ACTH to rise from 181 +/- 61 pg/ml to 539 +/- 99 pg/ml (P less than 0.01). The present data suggest that the opiate analogue loperamide is a potent inhibitor of ACTH secretion in patients with Addison's disease, which may be acting on mu receptors, since its effect is blocked by low doses of naloxone.

Topics: Addison Disease; Adrenocorticotropic Hormone; Adult; Aged; beta-Lipotropin; Depression, Chemical; Female; Humans; Loperamide; Male; Middle Aged; Piperidines; Random Allocation

Two tyrosine kinase inhibitors (TKIs), lenvatinib and vandetanib, are often used to treat advanced radioiodine-refractory differentiated thyroid cancer (RAI-R DTC) and medullary thyroid cancer (MTC), respectively. Fatigue is a common adverse event during treatment with these and other TKIs and a common cause of drug discontinuation or dosage reduction.. We evaluated the basal and stimulated adrenal function in 12 patients with advanced RAI-R DTC and MTC treated with lenvatinib or vandetanib, respectively. Ten patients complaining of fatigue showed a progressive ACTH increase with normal cortisol levels. Moreover, six of 10 patients had a blunted cortisol response after ACTH stimulation, thus confirming the diagnosis of primary adrenal insufficiency (PAI). The causal relationship between TKIs and PAI onset was also demonstrated by the repeated testing of adrenal function before and during treatment. Patients with PAI received cortisone acetate replacement therapy, with a substantial and prompt improvement in the degree of fatigue, as assessed by the Common Terminology Criteria for Adverse Events version 4.03, thus supporting the major impact of impaired adrenal function in the genesis of this adverse event.. We show that the occurrence of PAI may be a common cause of fatigue during lenvatinib and vandetanib treatment, and we therefore recommend testing adrenal function for a prompt start of replacement therapy to avoid treatment discontinuation, dosage reduction, and potentially severe PAI complications.

Topics: Addison Disease; Adult; Aged; Carcinoma, Neuroendocrine; Child; Cortisone; Dose-Response Relationship, Drug; Fatigue; Female; Follow-Up Studies; Humans; Male; Middle Aged; Phenylurea Compounds; Piperidines; Protein Kinase Inhibitors; Quinazolines; Quinolines; Thyroid Neoplasms; Treatment Outcome; Young Adult

The effect of loperamide - a peripheral opiate agonist - on plasma ACTH response to Corticotropin-releasing Hormone (CRH) has been investigated in 6 patients with Addison's disease. After placebo administration CRH induced a marked ACTH increase. After loperamide administration ACTH levels fell to a nadir of 135 +/- 76 pg/ml, and then CRH was still able to induce an ACTH increase; the pattern of ACTH response to CRH was slightly delayed. There was a significant difference between the two ACTH curves after CRH only in the early phase of the response. These data suggest that the inhibitory role of loperamide on ACTH secretion is exerted at supra-pituitary level, although a pituitary site of action can not be excluded.

Topics: Addison Disease; Adrenocorticotropic Hormone; Adult; Aged; Corticotropin-Releasing Hormone; Female; Humans; Kinetics; Loperamide; Male; Middle Aged; Piperidines