8th January 2024

Dosing

Starting on strong opioids can be with either immediate release or modified release preparations. Immediate release strategies are given as required for breakthrough pain, whereas modified release attempts to control patient’s pain over a 24-hour period. NICE recommends starting doses of:

• 5mg of oral morphine 4 hourly for immediate release strategy. or

• 15mg modified release morphine twice daily, plus 5mg immediate release as required for breakthrough pain.

The above demonstrates that even with a modified release strategy, it is important to co-prescribe an immediate release preparation. Typical teaching is that a breakthrough dose should be between 1/6 and 1/10th of the regular dose, with a maximum of 4 hourly. Taking a history will establish the dose that works for each individual patient – which could be higher or lower, and can be a guide.

Titration

Dose titration depends on the control of the patient’s pain and the medications they have required. Starting modified release preparation following an immediate-release strategy depends on the doses of immediate-release which have been required to control the pain. If a patient has taken four 5mg doses of immediate-release morphine in 24 hours:

• 4 x 5mg = 20mg daily morphine dose ÷ 2 = 10mg modified release twice a day
• 20mg morphine daily dose ÷ 6 = 3.3mg breakthrough dose

3.3mg is a difficult dose to draw up and give. Normally, morphine is given in measures of 1.25mg, so 2.5mg would be a good as required dose in this example.

Where modified release preparations have already been chosen but have been ineffective, dose increases will be based on breakthrough requirements. However, dose increases are usually kept at between 33-50% per day to avoid complications from rapid titration. Where the modified release dose is uptitrated, the breakthrough dose should also be increased if it is ineffective or not reaching the 1/6 – 1/10ᵗʰ thresholds.