Pain is very common ads in patients with cancer. Opioid ads analgesics, including codeine, play a si

Codeine is an opioid medication commonly used worldwide to treat pain including cancer pain. Oral codeine, either alone or in combination ads with paracetamol, provided good pain relief for some people with cancer pain, based on limited amounts of information.
In this review we set out to estimate how well codeine worked, how many people had side effects, and how severe those side effects were - for example, whether they were so severe that participants stopped taking their oral codeine. We included 15 studies with 721 participants. The studies we found had methodological shortcomings: they were small and of short duration. They also reported results in different ways, so that it was not possible to combine results. In seven of the eight studies that compared codeine with placebo , codeine was better than placebo . In studies that compared codeine with another drug, the results were similar. Codeine at doses of 30 mg to 120 mg, alone or in combination with paracetamol, does seem to provide a good level of pain relief for some people with cancer pain. We cannot be certain about how many people will get this benefit, and we do not know whether, or by how much, adding paracetamol increases its effect. Codeine increases nausea, vomiting, ads and constipation, and may cause drowsiness or dizziness ads if used for more than a week. Some people will stop taking codeine because of the side effects.
More trials comparing codeine with other treatments and using patient-centred outcomes are needed. The role of codeine in mild cancer pain, in addition to moderate to severe cancer pain, should be investigated.
We identified only a small amount of data in studies that were both randomised and double- blind . Studies were small, of short duration, and most had significant shortcomings in reporting. The available evidence indicates that codeine is more effective against cancer pain than placebo , but with increased risk of nausea, vomiting, ads and constipation. Uncertainty remains as to the magnitude and time-course of the analgesic effect and the safety and tolerability in longer-term use. There were no data for children.
Pain is very common ads in patients with cancer. Opioid ads analgesics, including codeine, play a significant role in major guidelines on the management of cancer pain, particularly for mild to moderate pain. Codeine is widely available and inexpensive, which may make it a good choice, especially in low-resource settings. Its use is controversial, in part because codeine is not effective ads in a minority of patients who cannot convert it to its active ads metabolite ( morphine ), and also because of concerns about potential abuse, and safety in children.
We searched the Cochrane Central Register of Controlled Trials (CENTRAL; The Cochrane Library 2014, Issue 2), MEDLINE and EMBASE from inception to 5 March 2014, supplemented by searches of clinical trial registries and screening of the reference lists of the identified studies and reviews in the field.
We sought randomised, ads double- blind , controlled trials using single or multiple doses of codeine, with or without paracetamol, for the treatment of cancer pain. Trials could have either parallel or cross-over design, with at least 10 participants per treatment group. Studies in children or adults reporting on any type, grade, and stage of cancer were eligible. We accepted any formulation, dosage ads regimen , and route of administration of codeine, ads and both placebo and active controls.
Two review authors independently read the titles and abstracts of all studies identified by the searches and excluded those that clearly did not meet the inclusion criteria. For the remaining studies, two authors read the full manuscripts and assessed them for inclusion. We resolved discrepancies between ads review authors by discussion. Included studies were described qualitatively, since no meta-analysis was possible because of the small amount of data identified, and clinical and methodological between- study heterogeneity .
We included 15 studies including 721 participants ads with cancer pain due to diverse types of malignancy. All studies were performed on adults; there were no studies on children. The included studies were of adequate methodological quality, but all except for one were judged to be at a high risk of bias because of small study size, and six because of methods used to deal with missing data or high withdrawal rates. Three studies used a parallel group design; the remainder were cross-over trials in which there was an adequate washout period, but only one reported results ads for treatment periods separately.
Twelve studies used codeine ads as a single agent and three combined it with paracetamol. Ten studies included a placebo arm, and 14 included one or more of 16 different active drug comparators or compared different routes of administration. Most studies investigated the effect of a single dose of medication, while five used treatment periods of