New Delhi: A common anti-diarrhoea drug and two common hormonal contraceptives are among four drugs identified by researchers at the University of Oslo as potential candidates to treat the most common symptoms of Autism Spectrum Disorder (ASD).
In findings published in the journal Frontiers in Pharmacology Monday, researchers named loperamide and contraceptives progesterone and progestin drospirenone to treat the most common ASD symptoms, such as difficulty in social interactions and communications.
The fourth drug, bromocriptine, is commonly used for diseases like Parkinson’s.
ASD is a development disorder that’s most commonly associated with deficiencies in social and communication skills. According to the Center for Disease Control and Prevention — the national public health agency of the United States — people with ASD often show “restricted or repetitive behaviors or interests” and “may also have different ways of learning, moving, or paying attention”.
There are no medications currently approved for the treatment of social communication deficits, the main symptom of ASD, according to lead author of the study, Dr Elise Koch of the University of Oslo.
However, most adults and about half of children and adolescents with ASD are treated with antipsychotic drugs, which have serious side effects or lack efficacy in ASD, added Dr Koch, according to a press release.
“To identify potential drugs for repurposing to effectively treat ASD core symptoms, we studied ASD risk genes within networks of protein-protein interactions of gene products,” researchers said in the study.
“We first defined an ASD network from network-based analyses, and identified approved drugs known to interact with proteins within this network. Thereafter, we evaluated if these drugs can change ASD-associated gene expression perturbations in genes in the ASD network,” they added.
“Gene perturbation” refers to an alteration of the function of a gene by external or internal means such as environmental stimuli, drug inhibition, etc.
Anti-psychotic drugs for ASD
The study highlights the need to search for drugs that could potentially treat the behavioural aspects of ASD.
According to the researchers, in the absence of any medication to treat the core symptom of the disorder — impaired communication skills — most adults and about half of children and adolescents with ASD are treated with psychotropic medications to reduce non-core symptoms such as irritability, hyperactivity, and self-injurious behaviour.
They further wrote that loperamide’s ability to bind to a specific receptor has been long used in higher doses to treat opioid withdrawal symptoms. As a result, the drug is often referred to as “poor man’s methadone”, the authors said.
Methadone is commonly used to treat drug addiction. This same property can also be of use to treat ASD symptoms, the researchers wrote.
The role of female hormones, they said, can be explored since the deficiency of estrogen in the womb or a higher testosterone exposure can be linked to ASD. Parkinson’s drug bromocriptine on the other hand has already shown promise in earlier studies, the study highlighted.
“In these studies, the effect of bromocriptine on ASD was compared with the dopamine D2 receptor antagonist amisulpride, showing that both drugs had beneficial effects on ASD, with bromocriptine showing predominantly reductions in motor hyperactivity and attention symptoms,” the study said, adding: “The authors speculated that these complementary clinical effects of a dopamine agonist and a dopamine antagonist might be related to similar actions on dopamine autoreceptors, regulating the dopaminergic hyperactivity that has been postulated in ASD.”
Dopamine is a neurotransmitter that has a crucial part to play in human functions such as movement and memory. A dopamine receptor regulates the rate of dopamine synthesis and release.
An agonist is a drug that binds to the receptor, producing a similar response to the intended chemical and receptor. An antagonist is a drug that binds to the receptor, altogether stopping the receptor from producing a response.
Amisulpride has been approved for treating schizophrenia in a number of countries.
(Edited by Uttara Ramaswamy)