Baaklini, L.G., Arruda, G.V., & Sakata, R.K. (2017). Assessment of the analgesic effect of magnesium and morphine in combination in patients with cancer pain: A comparative randomized double-blind study. American Journal of Hospice and Palliative Medicine, 34, 353–357.

To establish whether the analgesic effect of morphine improves in patients with cancer when administered in combination with magnesium

Patients with moderate or severe cancer pain and starting morphine were randomized to 656.6 mg sulfate BID or placebo.

• N: 40   
• AGE: Mean = 58.5 years in intervention group and 58.2 years in the placebo group
• MALES: 22 (55%)
• FEMALES: 18 (45%)
• KEY DISEASE CHARACTERISTICS: Not stated
• OTHER KEY SAMPLE CHARACTERISTICS: Only gender, age, height, and weight were reported. No information on current treatment

• SITE: Not stated/unknown   
• SETTING TYPE: Not specified    
• LOCATION: Not specified

PHASE OF CARE: Not specified

Prospective, randomized, double-blind trial

Pain intensity measured on 0 to 10 scale at baseline and weeks 1, 2, 3, and 4. Functional performance as assessed by Karnofsky and QOL assessed by the EORTC at first and last interview. Dose of morphine and side effects were recorded.

No difference in participant characteristic, pain intensity, morphine dose, functional performance, or QOL. Pain intensity was significantly reduced in both groups. No difference was found in the side effects of morphine except for constipation in week 1.

Morphine combined with magnesium did not lead to better analgesic effects, QOL, or functional performance.

• Small sample (< 100)
• Risk of bias (sample characteristics)
• Selective outcomes reporting
• Other limitations/explanation: Minimal details on study population

The use of morphine and magnesium did not induce a better analgesic effect or improve functional status or QOL.