# 14 - Gender differences in psychopharmacology

# Gender differences in psychopharmacology

© SPMM Course 
Gender differences in psychopharmacology 
 Antipsychotic response is shown to be superior in women 
 In chronically ill population, men are found to require twice as high a dose as women for 
effective maintenance. 
 Women have higher antipsychotic plasma levels than men after receiving the same dose 
of the drug. 
 The enzyme CYP1A2 appears to be less active in women than in men, leading to relatively 
higher blood concentrations of olanzapine and clozapine in women. 
 The volume of distribution of lipophilic drugs, such as antipsychotics, is greater in 
women than in men 
 In women, the blood volume is smaller, but lipid compartments are larger. This prolongs 
the half-life of antipsychotics in the body, leading to accumulation over time, a 
phenomenon that becomes important when administering depot injections. After a 
steady state is achieved, dosing intervals for women should be longer than for men. 
 Acute dystonia, long thought to be more prevalent among men, has been shown now to 
be more frequent in females at equivalent doses. Earlier clinical studies had not taken into 
account the fact that young male patients were commonly given higher doses than 
women. 
 Pulmonary embolism (a rare problem seen with drugs that have an affinity for the 
serotonin 5-HT2A receptor) and tardive dyskinesia appear to be more common in women.

© SPMM Course 
Notes prepared using excerpts from: 
 Appleby, L. et al (Ed) Postgraduate psychiatry: Clinical and scientific foundations. 2nd ed. Page 65 
 Bhugra, D & Bhui, K. Ethnic and cultural factors in psychopharmacology. Advances in Psychiatric 
Treatment (1999), vol. 5, pp. 89-95 
 http://www.dlc-ma.org/Resources/Health/Ethnic%20Psychopharmacology.html 
 Kaplan & Sadock's Synopsis of Psychiatry: Behavioral Sciences/Clinical Psychiatry, 10th Edition. 
Lippincott Williams & Wilkins 2007 
 Poolsup et al. Pharmacogenetics and psychopharmacology. Journal of Clinical Pharmacy and 
Therapeutics (2000) 25, 197-220 
 Seeman, M. (2004) Gender differences in the prescribing of antipsychotic drugs. Am J Psychiatry 
161:1324-1333. 
 Shiloh, R., Nutt, D. & Weizman, A. (2000). Atlas of psychiatric pharmacotherapy. Martin Dunitz, 
London. 
 Stahl, S. M. Essential psychopharmacology : neuroscientific basis and practical application 2nd ed 
Cambridge University Press 2000 
 Tsapakis, E. M., Basu, A. & Aitchison, K. J. (2004) Clinical relevance of discoveries in 
psychopharmacogenetics. Adv Psychiatr Treat, 10, 455-465. 
 Yudkin, P. (2004) Effectiveness of nicotine patches in relation to genotype in women versus men: 
randomised controlled trial. BMJ, 328, 989 -990. 
 Maixner D& Taylor MA. The efficacy and safety of electroconvulsive therapy. In Effective 
Treatments in Psychiatry. ed. Tyrer P. Cambridge University Press, 2008. 
 Wahlund, B., & von Rosen, D. (2003). ECT of major depressed patients in relation to biological and 
clinical variables: a brief overview. Neuropsychopharmacology: official publication of the American 
College of Neuropsychopharmacology, 28, S21-6. 
 Yatham, L. N., Liddle, P. F., Lam, R. W., Zis, A. P., Stoessl, A. J., Sossi, V., ... & Ruth, T. J. (2010). 
Effect of electroconvulsive therapy on brain 5-HT2 receptors in major depression. The British 
Journal of Psychiatry, 196(6), 474-479. 
 
DISCLAIMER: This material is developed from various revision notes assembled while preparing 
for MRCPsych exams. The content is periodically updated with excerpts from various 
published sources including peer-reviewed journals, websites, patient information leaflets and 
books. These sources are cited and acknowledged wherever possible; due to the structure of 
this material, acknowledgements have not been possible for every passage/fact that is 
common knowledge in psychiatry. We do not check the accuracy of drug related 
information using external sources; no part of these notes should be used as prescribing 
information.