Oral morphine represents a major progress in the treatment of pain, particularly in the cancer setting. The leading role in this progress has been played by British physicians and nurses (see introduction on palliative care and, in particular, the creation of a 'morphinic elixir' also known as 'St Christopher's elixir'). Slow release pills have also facilitated the larger and more practical use of morphine. French physicians have been generally more reticent in this field (poor teaching and practice, fear of toxicomania?), however morphine use is now the same throughout Europe and North America.
There are three different formulations:
Morphin elixir (St Christopher's elixir) which is a magistral preparation.
It associates morphine chlorhydrate (1 to 40 mg per ml) in 5‰ chloroform water. The patient generally drinks 10 ml of elixir every 4 hours (6 doses per day).
Regulat intake is the very basis of elixir morphine efficiency (short half life of morphine: generally 4h) and good tolerance (most side effects disappear quickly with the exception of constipation which should be prevented by lactulose).
Such regular intake (in particular night dosing) is a hindrance partly explaining the initial reluctance of French doctors to use this elixir (which has been used since 1934 at St Christopher's Hospital in London!).
The initial dosage is generally 6 x 10 mg per 24 hours.
Slow release oral formulations
Several commercial formulations of morphine sulfate are now available:
Moscontin (the first in use) is a tablet which should be administered every 12 hours, at a fixed time (for instance 8 AM - 8 PM). When changing from morphine elixir to Moscontin, the same dose should be prescribed (i.e. 30 mg twice a day is equipotent to 10 mg 6 times a day). Preventive laxative treatment is mandatory.
Skenan is a gelatine capsule containing a controlled-release suspension. The capsule can be opened and administered in an oral feeding catheter. Dosing and dosage are similar to Moscontin.
Kapanol is a slower release formulation (only one administration per day). However when titrating treatment, rapid-action formulations are generally necessary.
Rapid release oral formulations
They are most useful during the titration period of morphine (finding the right dosage).
They are used to rapidly balance severe pain and should be relayed by slow release formulations. They are also used to quickly relieve transitory acute pain attacks.
There are various formulations of this morphine sulfate: Sevredol and Actiskenan.
They are the same as for parenteral morphine. However, delay in their appearance may vary depending on formulations.
They are the same as for parenteral morphine: again, their appearance delay (longer) may vary with various formulations.
Same remarks.
Same remarks..
Generally, initial treatment involves a standard prescription: usually around 30 mg of Moscontin or equivalent twice daily for moderate to intense pain.
An oral form is given in the case of intercurrent pain. Usually, the patient may take 1/10th to 1/6th of the total daily slow release dosage (i.e. for a patient with 60 mg per day, the unit dosage of rapid morphine tablets is 10 mg) up to once every 4 hours.
We can take the example of a patient taking four doses of rapid morphine tablets in the next 24 hours (40 mg of morphine sulfate).
The following day; adjustment (50% of rapid morphine) will be made with slow release morphine (half dosage of 40 mg divided into two intakes: i.e. increase of 10 mg at each intake).
A laxative (lactulose) should always be simultaneously prescribed.
Oral morphine is a level III analgesic on the WHO ladder.
In most countries (as in France), oral morphine prescription is subject to specific legal guidelines.