Analgesic effect of paracetamol on cancer related pain in concurrent strong opioid therapy. A prospective clinical study.

INTRODUCTION: In palliative cancer care, when approaching death, swallowing difficulties and the burden of tablet intake frequently makes us reconsider each individual drug prescribed. Through the last two decades the routine of always combining a strong opioid with paracetamol has been widely spread in Sweden. Clinical experience has challenged this routine as many patients seem to manage equally well without paracetamol. To find out whether this might be of clinical importance, we wanted to perform a more systematic registration.
MATERIAL AND METHODS: Thirty-four incurable cancer patients with well controlled pain (NRSB4), treated by specialised palliative home care teams, with ongoing medication with the strong opioid paracetamol combination was recruited to this prospective clinical study. The effect of completely stopping paracetamol medication was evaluated four days later at follow-up.
RESULTS: At follow-up nine patients (26%) felt more pain compared to when they entered the study, two patients (6%) felt less pain and 23 (68%) felt no difference. When asked about their preference about future paracetamol treatment 18 patients (53%) wanted to stop taking it, six patients (18%) wanted to continue with regular paracetamol medication as before, and ten patients (29%) wanted to take paracetamol as needed. No clinical predictors of paracetamol response could be identified. DISCUSSION: The results of this study indicate that a critical evaluation, in every patient, of the subjective additive analgesic effect of paracetamol in concurrent strong opioid therapy is advisable and that stopping paracetamol medication not necessarily implies increased pain. Rather in some patients the cessation of paracetamol medication is experienced as a relief as pain control is maintained with a lesser tablet burden.