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.

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