Efficacy of theophylline in people with stable chronic obstructive pulmonary disease: a systematic review and meta-analysis

OBJECTIVES

To determine the efficacy of oral theophylline compared with placebo in people with stable chronic obstructive pulmonary disease (COPD).

METHODS

Systematic review of randomized-controlled trials comparing oral theophylline with placebo for a minimum of 7 days in people with stable COPD.

RESULTS

Twenty randomized-controlled trials were included in this review. The following outcomes showed significant improvement with theophylline compared with placebo: FEV1 and FVC both improved with theophylline (weighted mean difference [WMD] 0.10 L; 95% confidence interval [95% CI] 0.04-0.16 and WMD 0.21 L; 95% CI 0.10-0.32, respectively). VO2 max also improved with theophylline (WMD 195.27mL/ min; 95% CI 112.71-277.83), as did PaO2 and PaCO2 (WMD 3.18 mmHg; 95% CI 1.23-5.13 and WMD -2.36mmHg; 95% CI -3.52 to -1.21, respectively). Patients preferred theophylline over placebo (relative risk 2.27; 95% CI 1.26-4.11). Theophylline increased the risk of nausea compared with placebo (RR 7.67; 95% CI 1.47-39.94).

CONCLUSION

This review has shown that theophylline still has a role in the management of stable COPD, and is preferred by patients over placebo. However, the benefits of theophylline in stable COPD have to be weighed against the risk of adverse effects.

Effect of alkalinization on the local analgesic efficacy of ketamine in the abaxial sesamoid nerve block in horses

The objective of this study was to determine the effects of the alkalinization on the local analgesic efficacy of 1% ketamine in the abaxial sesamoid nerve block in horses. Thirty-six mature healthy horses were randomly assigned to four groups for the following treatments; an abaxial sesamoid block with 5 mL of saline solution (control saline); an abaxial sesamoid block with 5 mL of a solution containing 1% ketamine (KETs 1%); an abaxial sesamoid block with 5 mL of a solution containing saline solution and 0.5 mEq of sodium bicarbonate (control bicarbonate); and an abaxial sesamoid block with 5 mL of a solution containing 1% ketamine and 0.5 mEq of sodium bicarbonate (KETb 1%). All blocks were performed in one randomly selected front leg. To determine analgesia, hoof withdrawal from thermal stimulus from radiant heat lamp was assessed. Before each block, the hoof withdrawal reflex latency (HWRL) (time between lamp illumination and withdrawal of the hoof) was determined; after the block, local analgesic effects were determined using the heat lamp at 2 and 5 min after the injection and then every 5 min for 1 h. In KETs 1% group, there were significant increases in HWRL between basal values and values from 2 to 10 min after an abaxial sesamoid block. In KETb 1% group, significant increases in HWRL was collected between the basal value and values from 2 to 25 min following an abaxial sesamoid block. In KETs 1% group, of the nine horses, four had an abaxial sesamoid block that was unsuccessful. However, in KETb 1% group, only one of the nine horses had an abaxial sesamoid nerve block that was unsuccessful. The alkalinization of a 1% ketamine solution produced a more consistent and persistent local analgesia in horses when compared with 1% ketamine solution alone.

Oral theophylline for chronic obstructive pulmonary disease

BACKGROUND

Oral theophylline has, for many years, been used as a bronchodilator in patients with COPD. Despite the introduction of new drugs, and its narrow therapeutic index, theophylline is still recommended for COPD treatment.

OBJECTIVES

To determine the effectiveness of oral theophylline when compared to placebo in patients with stable COPD.

SEARCH STRATEGY

The Cochrane Airways Review Group and Cochrane Controlled Clinical Registers were searched.

SELECTION CRITERIA

All studies were randomised controlled trials (RCTs).

DATA COLLECTION AND ANALYSIS

Data were independently abstracted and the methodological quality assessed by two reviewers.

MAIN RESULTS

Twenty RCTs met the inclusion criteria. Concomitant therapy varied from none to any other bronchodilator plus corticosteroid (oral and inhaled). The following outcomes were significantly different when compared to placebo. FEV1 improved with treatment: Weighted Mean Difference (WMD) 100 ml; 95% Confidence Interval (95%CI) 40, 160 ml. Similarly for FVC: WMD 210 ml 95%CI 100, 320. Two studies reported an improvement in VO2max; WMD 195 ml/min, 95%CI 113,27). At rest, PaO2 and PaCO2 both improved with treatment (WMD 3.2 mmHg; 95%CI = 1.2, 5., and WMD -2.4 mmHg; 95%CI = -3.5, -1.2, respectively). Walking distance tests did not improve (4 studies, Standardised Mean Difference 0.30, 95%CI -0.01, 0.62), neither did Visual Analogue Score for breathlessness isn two small studies (WMD 3.6, 95%CI -4.6, 11.8). The Relative Risk (RR) of nausea was greater with theophylline (RR 7.7; 95%CI 1.5, 39.9). However, patients' preference for theophylline was greater than that for placebo (RR 2.27; 95%CI = 1.26, 4.11). Very few patient withdrew from these studies for any reason.

REVIEWER'S CONCLUSIONS

Theophylline has a modest effect on FEV1 and FVC and slightly improves arterial blood gas tensions in moderate to severe COPD. These benefits were seen in patients receiving a variety of different concomitant therapies. Improvement in exercise performance depended on the method of testing. There was a very low dropout rate in the studies that could be included in this review, which suggests that recruited patients may have been known by the investigators to be theophylline tolerant. This may limit the generalisability of these studies.

Lung cancer risk in Venice: a population-based case-control study

Populations resident in the historical town of Venice and in the inland industrial city of Mestre are at different risk of exposure to environmental pollutants. This case-control study compares the risk of developing lung cancer in the two populations in relation to known risk factors for this neoplasm. A retrospective study of 305 incident cases of lung and 447 frequency-matched population controls was conducted through a standard questionnaire on main risk factors for lung cancer. Completeness of cases was checked against the Venetian Cancer Registry files. The results indicate that lung cancer risk associated with tobacco smoking was high in both areas, although more elevated in Venice islands among heavy smokers. An elevation of risk was associated with housing without a heating system, possibly suggesting a role of worse hygienic conditions. An increased risk associated with exposure to occupational carcinogens was detected in the inland area. In conclusion, lung cancer risk due to tobacco smoking largely affects both the populations, while other risks such as occupation or housing conditions appear to be more population-specific.