About Our Practice

Established in 1989


The Clinic was established in 1989 by Dr Noreen O’Hanrahan and relocated to its current premises in 2006.  Dr Noreen O’Hanrahan was joined by Dr Gillian McLaughlin in 2010 and Dr Thomas O’Byrne in 2018. After a long successful career Dr Noreen O’Hanrahan retired in 2022 and will be missed both by her patients and the clinic. 

Along with Dr Noreen O’Hanrahan, practice manager Brendan Geraghty and secretary Ann Keegan have also both recently retired and will be missed. 

Our clinic has continued with Dr Gillian McLaughlin and Dr Thomas O’Byrne, our practice nurse Vanessa Mulcahy, supported by our dedicated administration team of secretaries Kristina O’Regan, Patricia Haughton and practice manager Anne Burns.

Meet Our Staff

Dr Gillian McLaughlin

Dr Gillian McLaughlin

(BSc, MBChB, DRCOG, DCCH, MRCGP) graduated from the University of St Andrews University and then from Manchester University.

Gillian completed her General Practice training in Edinburgh and worked as a GP partner in London before moving with her family to Dublin in 2005. Gillian has been working in Mount Merrion Medical Clinic since 2009.   

Gillian has a special interest in all aspects of Woman’s Health including contraception, pre-conception investigations, ante-natal and postnatal care and menopause management plus child health – from the new-born baby to the adolescent.  She is also interested in ongoing chronic disease management, having completed a Certificate in Diabetes care in 2019.

Dr Thomas O'Byrne

Dr Thomas O'Byrne

(MICGP, MB BCh, BAO, DRCOG) is a graduate of University College Dublin.

Following two years of surgical training Thomas decided to specialise in general practice and completed postgraduate training with the south east GP training scheme.

He gained international experience by working in Australia for three years prior to returning to Dublin to join Mount Merrion Medical Clinic in 2018.

He manages patients for the full range of issues that arise in general practice and has a special interest in chronic disease management, men’s health and minor surgical procedures.


Vanessa Mulcahy


Nurse Vanessa Mulcahy joined our practice in 2020. Vanessa is a highly experienced nurse, and has worked in acute hospitals in Ireland and abroad. 

She has a special interest in cardiology, and operates the ECG, vaccine, phlebotomy and cervical smear clinics as well as assisting with minor surgical procedures.

Mairead Keys

Mairead Keys

Foot Health Practitioner (RGN MCFHP MAFHP)

Mairead is a member of the British Institute of Chiropodists and Podiatrists and the College of Foot Health Practitioners.  Building on years of experience as a General Nurse in Ireland and overseas, she has specialised in foot health care for the last eight years.

As a keen walker and aspiring golfer, she stresses to her patients the importance of looking after their feet and maintaining mobility into later life.


Dr Noreen O’Hanrahan (Retired 2022)

(MB, BCh, BAO, LRCSI, LRCPI, DCH, D Obs, FPC) is a graduate of the Royal College of Surgeons in Ireland - Retired 2022.

Dr Noreen worked in several Irish hospitals and established the practice in 1989.  She has post-graduate qualifications in infertility, family planning, contraception, child health, dermatology.

She has a special interest in antenatal care, mother and baby health, paediatrics, and adolescent health.  “Being a mother really helped me as a GP” says Dr Noreen, “having to combine clinical work and family life, I can better understand the demands on families”.

She also takes an interest in HRT, the menopause, and care of the older patient.  She has worked extensively with the “Living Well With Dementia” project locally. She will be missed both by her patients and the clinic following her retirement in 2022. 

Dr Thomas O'Byrne

Brendan Geraghty (Retired 2022)

BA, MSc Practice Manager

Brendan is a Work and Organisational Psychologist and was with the practice from the outset until his retirement in 2022.

Ann Keegan

Ann Keegan (Retired 2022)


Ann Keegan joined us in 2007 from St Vincent’s University Hospital, intending to work here for 2 years but stayed until her retirement in 2022. 

As the first point of contact for many patients, Ann was a key member of our team, bringing empathy, tact, communication and organisational skills, a friendly nature and attention to detail to her role.