Research Article - (2012) Volume 1, Issue 3

Drug Interaction in Psycho-Oncology: A Retrospective Glance over the Polymedication and Comorbidities in a Portuguese Psycho-Oncology Service

Margarida Duarte1*, Cristina Miguel2 and Emília Albuquerque3
1Leiria - Pombal Hospital Center, Montalvo, Portugal
2Coimbra University Hospital Center, Coimbra, Portugal
3Portuguese Institute of Oncology Francisco Gentil of Coimbra (IPOCFG), Coimbra, Portugal
*Corresponding Author: Margarida Duarte, Leiria-Pombal Hospital Center, Rua Do Tojal No6, 2250-241, Montalvo, Portugal Email:


Introduction: The evaluation and prescription of psychotropic drugs in oncologic setting is of particular importance because of cancer patient´s susceptibility to drug interactions.
Objectives: Describe the frequency and type of comorbidities and the standard prescription of pharmaceuticals in a sample of cancer patients. Secondarily, reflect on the importance of clinical pharmacological interactions in this context, particularly in the prescription of psychotropic drugs. Material/methods: Descriptive study of a sample of patients referred for the first time to the Psycho-Oncology Unit of IPOCFG, between October and December 2011. A retrospective collection of the socio-demographic and clinical variables was made by consulting the clinical processes.
Results: From the sample of 60 patients included for analysis, 48,3% of the patients were on antineoplasic medication, 46,7% had prior psychiatric history and 70% were on psychotropic drugs; 75% presented other comorbidities. Only 8,3% of patients were free of medication and, from those under it, 63,6% consumed three or more distinct pharmacological classes.
Conclusions: There is a high frequency of co-morbidities and co-prescription of several classes of drugs which pose cancer patients at risk of interactions. It is important that physicians are able to predict these phenomena to prevent the loss of efficiency and minimize the adverse effects, particularly of antineoplastic.

Keywords: Psycho-Oncology; Comorbidities; Polimedication; Drug interactions


Psychiatric morbidity is increasingly recognized and valued in oncology as a source of anguish and suffering and also because cancer patients who receive adequate treatment of their mental health are more compliant with chemotherapy, in addition to experiencing improved quality of life [1]. Reports also suggest that depression is associated with increased morbidity in cancer patients [2]. The mourning of current and anticipated losses, the fear of death, concerns with the loved ones, the effect of some chemotherapeutics in mood and biological characteristics of the tumor [1] have been implicated in the genesis of this suffering. According to the literature, about 50% of these patients are people with mental illness, mainly adjustment disorders (4-35%) followed by major depressive disorder (3-36%) [3,4-6] and, for some authors, delirium [7]. However, only 30% of the clinical psychiatric syndromes associated with cancer are identified by their doctors [8].

Depression is associated with lower quality of life, increased subjective perception of pain, suicidal thoughts, wish for hastened death and a worse prognosis [3,9-11].

In addition to the psychiatric context, psychoactive drugs are known to have a multiplicity of actions that can play a key role in the care of patients with cancer (e.g. in the control of anorexia, nausea, vomiting and pain management) [12]. However, drug interactions can lead to increased toxicity or loss of effectiveness when certain medications are prescribed at the same time [3]. Drugs such as antihypertensives, corticosteroids and/or antineoplastic agents (procarbazine, vincristine, L-asparaginase, interferon, tamoxifen) have been considered in several studies as medical risk factors for depression in patients with cancer [7,13].

Cancer patients are a physically vulnerable population, usually, taking several drugs and, therefore, in particular risk of drug interactions. It is particularly important to carefully evaluate and orientate psychopharmacologic treatment of these patients.

In the literature there are few studies with patient samples considering the importance of interactions and psychiatric comorbidities in cancer patients.

Materials and Methods

We made a descriptive analysis of a sample of patients referred for the first time to Psycho-Oncology Unit of the Portuguese Institute of Oncology Francisco Gentil in Coimbra, between October and December 2011. This is a pilot study where all the patients observed during this period, outpatient or inpatient care, were included. We looked for socio-demographic and clinical variables: psychiatric and medical comorbidities, nature and treatment of the disease cancer, psychiatric diagnosis and the categories of drugs taken by patients at the date of evaluation.


Of the 73 first queries recorded during the period in which the study took place, 13 clinical processes were excluded due to the absence of Oncologic pathology, because it was not the patient’s first contact with the unit or because the process was not available at the time of data collection. Thus, the final sample included 60 clinical cases (n = 60).

The sample was composed by 57% of female patients, with a mean age of 57,4 years; in about half of the cases (51,7%) the patients were referred to the Psychiatry Unit through the Oncologic service where a program of psychiatric morbidity screening is implemented using the Distress Thermometer [14]. On average, 22,7 months had lapsed between the diagnosis and the date of the first psychiatric consultation. Breast cancer was the most frequent diagnosis (36.7%), followed by the digestive system and genito-urinary tract cancer, both at 18.3% of cases. In most cases (70%) no remote metastases were detected. Concerning the disease stage, 36.7% of patients were in remission, 30% at initial treatment and 15% were under palliative care.

We found that 48% of patients were treated with some anticancer agent and 28% were still not treated with antineoplastic agents, however, an important portion could be medicated briefly, since 10% were in the process of exploration and study of its cancer disease. Of the total sample, only 8.3% of patients were not taking any pharmacological medication and, from the ones on medication, 63.6% were taking drugs from three or more distinct pharmacological classes.

In addition to the psychiatric pathology and cancer, hypertension, cardiac pathology, dyslipidemia, endocrine and liver diseases stand out as comorbidities (Table 1).

Comorbidities Other pharmacologic classes (number)
Psychiatric 51,7%
Hypertension 34,5%
Dyslipidaemia 34,5%
Endocrine pathology 13,8%
Cardiac disease 10,3%
Hepatic disease 3,4%
Others * 27,6%
No 27,6%
< 3classes: 27,6%
3 - 6 classes: 65,1%
> 6 classes: 6,9%
* Respiratory disease, benign prostatic hypertrophy, anemia, glaucoma, chronic renal failure, autoimmune pathology, stroke, fibromyalgia, chronic constipation

Table 1: Comorbidities and pharmacological drugs prescribed to patients treated with some antineoplastic drugs, 48% (n=29).

A history of prior psychiatric follow-up was found in 46.7% of patients and 70% of them were already on some class of psychoactive drugs.

A proportion of patients (18.3%) lacked psychiatric diagnosis, presenting symptoms considered to be adaptive and without causing significant emotional distress or functional deficits (examples: fear about the future, anxiety, death-related concerns with members of the family). Psychiatric pathology was present on 81.7% of patients, mainly, adjustment disorders (40.8%) and depressive disorders (30.6%) as shown in Figure 1 [diagnoses according to International Classification of Diseases, version 10 (ICD-10)] [15]. Of these patients, 27 (54%), reported history of psychiatric follow-up and 23 (46%) had no prior coverage.


Figure 1: Main Psychiatric diagnosis (ICD 10) of patients referred for the first time to Psycho-Oncology (Others: mainly bipolar disease and Organic disorders)

Discussion and Conclusions

Approximately half of the cases referred had pre-existing psychiatric pathology and more than two thirds had a psychiatric diagnosis at the moment of evaluation. Adaptation disorders and depression were the most common. As shown by our results, the Distress Thermometer was a useful tool implicated in the reference of patients assisted in Psychiatry Unit. Half of the patients were on antineoplastic treatment and more than half were taking more than three drug classes prescribed simultaneously including psychoactive drugs.

Given the increased vulnerability of these patients and the known adverse effects of some interactions, it is important that doctors know the rationale underlying mechanisms of biotransformation of drugs they prescribe as well as the possible interactions with other classes and iatrogenic effects of medication.

It is also important to consider the screening and treatments for distress in cancer setting other than psychopharmacologic drugs.

These results outline the importance of promoting the development of scientific research on drug interactions, crossing information from different therapeutic classes to provide adequate psychiatric treatment for patients with cancer.


Both the little sample size and the unicentric methodology used compromises the external validity of the study. The use of descriptive statistical methods limits the projection of the conclusions.


  1. Kadan-Lottick NS, Vanderwerker LC, Block SD, Zhang B, Prigerson HG (2005) Psychiatric disorders and mental health service use in patients with advanced cancer: a report from the coping with cancer study. Cancer 104: 2872-2881.
  2. Breitbart W, Bruera E, Chochinov H, Lynch M (1995) Neuropsychiatric syndromes and psychological symptoms in patients with advanced cancer. J Pain Symptom Manage 10: 131-141.
  3. Miguel C, Albuquerque E (2011) Drug interaction in psycho-oncology: antidepressants and antineoplastics. Pharmacology 88: 333-339.
  4. Pasquini M, Biondi M, Costantini A, Cairoli F, Ferrarese G, et al.(2006) Detection and treatment of depressive and anxiety disorders among cancer patients: feasibility and preliminary findings from a liaison service in an oncology division. Depress Anxiety 23: 441-448.
  5. Grassi L, Nanni MG, Uchitomi Y, Riba M, Kissane DW, et al. (2010 Pharmacotherapy of Depression in People with Cancer Depression and Cancer. Wiley.
  6. Massie MJ (2004) Prevalence of depression in patients with cancer. J Natl Cancer Inst Monogr 32: 57-71.
  7. Sadock B J, Sadock V A (2007) Kaplan & Sadock's: Compêndio de Psiquiatria - Ciência do Comportamento e Psiquiatria Clínica. Porto Alegre: Artmed 9: 892-893.
  8. Fallowfield L, Ratcliffe D, Jenkins V, Saul J (2001) Psychiatric morbidity and its recognition by doctors in patients with cancer. Br J Cancer 84: 1011-1015.
  9. Grassi L, Holland JC, Johansen C, Koch U, Fawzy F(2011) Psychiatric concomitants of cancer, screening procedures, and training of health care professionals in oncology: the paradigms of psycho-oncology in the psychiatry field. Advances in Psychiatry. 2: 59-66.
  10. Hjerl K, Andersen EW, Keiding N, Mouridsen HT, Mortensen PB, et al. (2003) Depression as a prognostic factor for breast cancer mortality. Psychosomatics 44: 24-30.
  11. Stommel M, Given BA, Given CW (2002) Depression and functional status as predictors of death among cancer patients. Cancer 94: 2719-2727.
  12. Stiefel FC, Kornblith AB, Holland JC (1990) Changes in the prescription patterns of psychotropic drugs for cancer patients during a 10-year period. Cancer 65: 1048-1053.
  13. Decat CS, Laros JA, Araujo TCCF (2009) Termômetro de Distress: validação de um instrumento breve para avaliação diagnóstica de pacientes oncológicos. Psico-USF. Itatiba 14: 253-260.
  14. Organização Mundial de Saúde (1992) Cid 10 - Classificação de Transtornos Mentais ede Comportamento da CID-10 Descrições Clínicas e Diretrizes Diagnósticas. Porto Alegre: Artmed.
  15. Gelder M G, Andreasen N C, López-Ibor Jr J J, Geddes J R (2009) New Oxford Textbook of Psychiatry. Oxford University Press 2: 1100-1105.
Citation: Duarte M, Miguel C, Albuquerque E (2012) Drug Interaction in Psycho- Oncology: A Retrospective Glance over the Polymedication and Comorbidities in a Portuguese Psycho-Oncology Service. Adv Pharmacoepidem Drug Safety 1:113.

Copyright: © 2012 Duarte M, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.