Use of low dose naltrexone and hydroxycarbamide for mast cell disorders (ISM, MCAS, HaT)

B  Myers; P  Chudakou

doi:10.15406/jcpcr.2025.16.00591

Journal of

eISSN: 2373-633X

Cancer Prevention & Current Research

Mini Review Volume 16 Issue 5

Use of low dose naltrexone and hydroxycarbamide for mast cell disorders (ISM, MCAS, HaT)

B Myers, P Chudakou

University Hospitals of Leicester, UK

Correspondence: Dr Bethan Myers, University Hospitals of Leicester, UK

Received: December 09, 2025 | Published: December 12, 2025

Citation: Myers B, Chudakou P. Use of low dose naltrexone and hydroxycarbamide for mast cell disorders (ISM, MCAS, HaT). J Cancer Prev Curr Res. 2025;16(5):134‒135. DOI: 10.15406/jcpcr.2025.16.00591

Download PDF

Introduction

Mast cells (MC), in addition to being present in bone marrow, are ubiquitous lining the gut, lungs, uterus, bladder as well as the brain. MC can release >1000 mediators, causing multiple symptomologies resulting in difficulties in symptom control in mast cell disorders.

There are several mast cell disorders that cause mast cell symptoms resulting in difficulties in symptom control in mast cell disorders. There are several mast cell disorders that cause mast cell symptoms including Systemic Mastocytosis (ISM), Mast Cell Activation Syndrome (MCAS) and Hereditary alpha tryptasemia (HaT) Hydroxycarbamide together with low dose naltrexone (LDN) have been shown to be helpful together with antihistamines in mast cell patients, in calming their symptoms. Hydroxycarbamide is an old and well known drug in treatment of myeloproliferative conditions and also in Sickle Cell conditions, with cell load reduction and pain reduction in HbSS.

LDN is used as an extremely low dose compared to standard dose Naltrexone, and we prescribed it as 4.5mg od.

Method

Patients were identified from the local data base and review of all symptoms were recorded by patients (Table 1). All the patients in this study were female.

	Date:______/_____/_______
Mast cell activation syndrome symptom index
NAME:	NHS no.
Frequency: 0=never, 1 = once/mo., 2 = few times/mo., 3 = few times/wk., 4 = few times/day, 5 = constantly
Severity: 0 = never, 1 = mild, 2 = mild to moderate, 3 = moderate to severe, 4 = severe
GENERAL - Constitutional	Frequency	Severity
Chills
Fever
Fatigue
Weight loss
Skin
Flushing
Flushing with sweating
Itchy skin
Hives (red, itchy bumps)
Swelling of lips, eyes or face
Respiratory
Itchy eyes or nose
Runny nose
Blocked nose
Problems taking a deep breath (throat swelling)
Feeling short of breath
Hoarseness
Wheezing
Cardiovascular
Palpitations with rapid heart beats
Fainting or near fainting episodes
Chest pain
Gastrointestinal
Diarrhoea
Abdominal pain
Abdominal cramping
Bloating
Constipation and / or diarrhoea
Heartburn
Nausea
Neurology
Headaches
Tingling or numbness
Trouble with memory /thinking
Sleep problems
Dizziness (head spinning)
Anxiety or panic attacks / depression
Musculo-skeletal
Muscle pain and / or tenderness
Joint pain
Obstetric/Gynae
Heavy periods? Endometriosis? PCOS ?
Pregnancy issues
? EDS Y/N
? PoTs Y/N

Medications were commenced individually and gradually escalated, and patients completed document 1 again in clinic after treatment for three months.

The main aims of this project were to examine the use of LDN and Hydroxycarbamide in patients with mast cell disorders and also to assess clinical responses in patients with multiple symptoms.¹

Results

Forty MCAS patients received LDN alone and showed improvement in joint pains, fatigue, gut and skin symptoms, whereas 20 MCAS patients did not tolerate LDN.²

Two female patients with c-kit positive ISM had bone pain which responded to LDN as well as their gut symptoms improving in both cases. A further patient with MCAS received a combination of Hydroxycarbamide and LDN, again with significant improvement in bone pain, fatigue, gut and skin symptoms.³

All the patients received mast cell stabilisers and antihistamines in addition prior to starting LDN +/- hydroxyurea, and all on this last medication had regular FBC blood tests

Conclusion

Mast cell reactions are often difficult to manage, but the majority of our cohort benefitted from one or both of these drugs. LDN is an unfamiliar drug in most hospitals in the UK, but due to its positive effects in the majority of our patients, we have stocked it in our hospital pharmacy.

We recommend consideration of this drug combination and LDN can be sourced from Dickson’s Chemist in Glasgow, which has considerable experience of LDN over many years.