Antalarmin

Overview
Antalarmin is a drug which acts as a CRF-1 antagonist.

Corticotropin releasing factor (CRF), also known as Corticotropin releasing hormone, is an endogenous peptide hormone which is released in response to various triggers such as chronic stress and drug addiction. This then triggers the release of corticotropin (ACTH), another hormone which is involved in the physiological response to stress. Chronic release of CRF and ACTH is believed to be directly or indirectly involved in many of the harmful physiological effects of chronic stress, such as excessive glucocorticoid release, stomach ulcers, anxiety, depression, and development of high blood pressure and consequent cardiovascular problems.

Antalarmin is a non-peptide drug which blocks the CRF-1 receptor, and consequently reduces the release of ACTH in response to chronic stress. This has been demonstrated in animals to reduce the behavioural responses to stressful situations, and it is proposed that antalarmin itself, or more likely newer CRF antagonist drugs still under development, could be useful for reducing the adverse health consequences of chronic stress in humans, as well as having possible uses in the treatment of conditions such as anxiety, depression and drug addiction.

Results so far have had limited success, with various CRF antagonists being tested, which showed some antidepressant effects, but failed to produce an effect comparable with conventional antidepressant drugs. However more positive results were seen when antalarmin was combined with an SSRI antidepressant, suggesting a potential for synergistic effect. Encouraging results have also been observed using antalarmin as a potential treatment for anxiety and stress-induced hypertension.

Chronic antalarmin treatment also showed antiinflammatory effects and has been suggested as having potential uses in the treatment of inflammatory conditions such as arthritis, as well as stress-induced gastrointestinal ulcers and irritable bowel syndrome.

Mixed results have been seen in research into the use of antalarmin and other CRF-1 antagonists in the treatment of drug addiction disorders. Tests of antalarmin on cocaine use in cocaine-addicted monkeys produced only slight reductions of use that were not statistically significant, however in tests on cocaine-addicted rats, antalarmin did prevent dose escalation with prolonged use, suggesting that it might stabilise cocaine use and prevent it increasing over time, although without consistently reducing it.

Antalarmin also showed positive effects in reducing withdrawal syndrome from chronic opioid use, and significantly reduced self-administration of ethanol in ethanol-addicted rodents.