Receptors, adrenergic opioid antagonists

As an opioid antagonist, alvimopan interacts selectively with gastrointestinal p opioid receptors with no central nervous system activity. It has not shown affinity for non-opioid receptors such as adrenergic, dopaminergic, histaminergic, GABAergic, or cholinergic receptors [1,2,4]. 

Opioids, benzodiazepines, barbiturates, corticosteroids, dopamine agonists (e.g., amantadine, bromocriptine, levodopa, pergolide, pramipexole, ropinirole), H2-receptor antagonists, anticholinergics (e.g., diphenhydramine, trihexylphenidyl), P-adrenergic blockers, clonidine, methyldopa, carbamazepine, phenytoin, baclofen, cyclobenzaprine, lithium, antidepressants (e.g., tricyclic antidepressants, selective serotonin reuptake inhibitors), and interleukin-2... 

Ondansetron Alcohol Ondansetron is a serotonin 5-HT3 receptor antagonist, with low affinity for al-adrenergic, 5-HTiB, 5-HTiC, and J-opioid receptors [251]. It is used primarily to treat nausea and vomiting (antiemetic) following chemotherapy. 

The physical and the subjective symptoms that follow withdrawal of opioids from the dependent subject are rapidly reversed by clonidine (12.53) without causing euphoria. This result seems to be connected with a finding that chronic morphine administration in the rat increases the number of a-adrenergic receptors in the brain, and that clonidine is an efficient antagonist for these receptors (Redmond and Kleber, 1980). Some clinics are using clonidine as part of their withdrawal programme. 

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