DOSAGE AND ADMINISTRATION
(SEE ALSO: CLINICAL PHARMACOLOGY, WARNINGS, AND PRECAUTIONS SECTIONS)
MS CONTIN IS AN OPIOID AGONIST AND A SCHEDULE II CONTROLLED SUBSTANCE WITH AN ABUSE LIABILITY SIMILAR TO OTHER OPIOID AGONISTS. MORPHINE AND OTHER OPIOIDS USED IN ANALGESIA CAN BE ABUSED AND ARE SUBJECT TO CRIMINAL DIVERSION.
MS CONTIN TABLETS ARE TO BE SWALLOWED WHOLE, AND ARE NOT TO BE BROKEN, CHEWED, DISSOLVED OR CRUSHED. TAKING BROKEN, CHEWED, DISSOLVED, OR CRUSHED MS CONTIN TABLETS LEADS TO RAPID RELEASE AND ABSORPTION OF A POTENTIALLY FATAL DOSE OF MORPHINE.
Physicians should individualize treatment in every case, initiating therapy at the appropriate point along a progression from non-opioid analgesics, such as non-steroidal anti-inflammatory drugs and acetaminophen to opioids in a plan of pain management such as those outlined by the World Health Organization, the Federation of State Medical Boards Model Guidelines, or the American Pain Society. Healthcare professionals should follow appropriate pain management principles of careful assessment and ongoing monitoring (see BOXED WARNING).
MS CONTIN® Tablets are a controlled-release oral formulation of morphine sulfate indicated for the management of moderate to severe pain when a continuous, around-the-clock analgesic is needed for an extended period of time. The controlled-release nature of the formulation allows it to be administered on a more convenient schedule than conventional immediate-release oral morphine products. (See CLINICAL PHARMACOLOGY; PHARMACOKINETICS AND METABOLISM.) However, MS CONTIN does not release morphine continuously over the course of a dosing interval. The administration of single doses of MS CONTIN on a q12h dosing schedule will result in higher peak and lower trough plasma levels than those that occur when an identical daily dose of morphine is administered using conventional oral formulations on a q4h regimen. The clinical significance of greater fluctuations in morphine plasma level has not been systematically evaluated.
As with any potent opioid drug product, it is critical to adjust the dosing regimen for each patient individually, taking into account the patient's prior opioid and non-opioid analgesic treatment experience. Although it is clearly impossible to enumerate every consideration that is important to the selection of initial dose and dosing interval of MS CONTIN, attention should be given to 1) the daily dose, potency, and precise characteristics of the opioid the patient has been taking previously (e.g., whether it is a pure agonist or mixed agonist/antagonist), 2) the reliability of the relative potency estimate used to calculate the dose of morphine needed [N.B. potency estimates may vary with the route of administration], 3) the degree of opioid tolerance, if any, and 4) the general condition and medical status of the patient.
The following dosing recommendations, therefore, can only be considered suggested approaches to what is actually a series of clinical decisions in the management of the pain of an individual patient.
During periods of changing analgesic requirements including initial titration, frequent contact is recommended between physician, other members of the healthcare team, the patient, and the caregiver/family.
Conversion from Immediate-Release Oral Morphine to MS CONTIN
A patient's daily morphine requirement is established using immediate-release oral morphine (dosing every 4 to 6 hours). The patient is then converted to MS CONTIN® in either of two ways: 1) by administering one-half of the patient's 24-hour requirement as MS CONTIN on an every 12-hour schedule; or, 2) by administering one-third of the patient's daily requirement as MS CONTIN on an every eight hour schedule. With either method, dose and dosing interval is then adjusted as needed (see discussion below). The 15 mg tablet should be used for initial conversion for patients whose total daily requirement is expected to be less than 60 mg. The 30 mg tablet strength is recommended for patients with a daily morphine requirement of 60 to 120 mg. When the total daily dose is expected to be greater than 120 mg, the appropriate combination of tablet strengths should be employed.
Conversion from Parenteral Morphine or Other Opioids (Parenteral or Oral) to MS CONTIN
MS CONTIN can be administered as the initial oral morphine drug product; in this case, however, particular care must be exercised in the conversion process. Because of uncertainty about, and intersubject variation in, relative estimates of opioid potency and cross tolerance, initial dosing regimens should be conservative. It is better to underestimate the 24-hour oral morphine requirement than to overestimate. To this end, initial individual doses of MS CONTIN should be estimated conservatively. In patients whose daily morphine requirements are expected to be less than or equal to 120 mg per day, the 30 mg tablet strength is recommended for the initial titration period. Once a stable dose regimen is reached, the patient can be converted to the 60 mg or 100 mg tablet strength, or an appropriate combination of tablet strengths, if desired.
Estimates of the relative potency of opioids are only approximate and are influenced by route of administration, individual patient differences, and possibly, by an individual's medical condition. Consequently, it is difficult to recommend any fixed rule for converting a patient to MS CONTIN directly. The following general points should be considered, however.
- Parenteral to oral morphine ratio: Estimates of the oral to parenteral potency of morphine vary. Some authorities suggest that a dose of oral morphine only three times the daily parenteral morphine requirement may be sufficient in chronic use settings.
- Other parenteral or oral opioids to oral morphine: Because there is lack of systematic evidence bearing on these types of analgesic substitutions, specific recommendations are not possible.
Physicians are advised to refer to published relative potency data, keeping in mind that such ratios are only approximate. In general, it is safer to underestimate the daily dose of MS CONTIN required and rely upon ad hoc supplementation to deal with inadequate analgesia. (See discussion which follows.)
Use of MS CONTIN as the First Opioid Analgesic
There has been no systematic evaluation of MS CONTIN as an initial opioid analgesic in the management of pain. Because it may be more difficult to titrate a patient using a controlled-release morphine, it is ordinarily advisable to begin treatment using an immediate-release formulation. (See Special Instructions for MS CONTIN® 100 and 200 mg Tablets)
Considerations in the Adjustment of Dosing Regimens
Whatever the approach, if signs of excessive opioid effects are observed early in a dosing interval, the next dose should be reduced. If this adjustment leads to inadequate analgesia, that is, "breakthrough" pain occurs late in the dosing interval, the dosing interval may be shortened. Alternatively, a supplemental dose of a short-acting analgesic may be given. As experience is gained, adjustments can be made to obtain an appropriate balance between pain relief, opioid side effects, and the convenience of the dosing schedule.
In adjusting dosing requirements, it is recommended that the dosing interval never be extended beyond 12 hours because the administration of very large single doses may lead to acute overdose. (N.B. MS CONTIN is a controlled-release formulation; it does not release morphine continuously over the dosing interval.)
For patients with low daily morphine requirements, the 15 mg tablet should be used.
Special Instructions for MS CONTIN 100 and 200 mg Tablets
(For use in opioid-tolerant patients only.)
MS CONTIN 100 mg and 200 mg tablets are for use only in opioid-tolerant patients requiring daily morphine equivalent dosages of 200 mg or more for the 100 mg tablet and 400 mg or more for the 200 mg tablet. It is recommended that these strengths be reserved for patients that have already been titrated to a stable analgesic regimen using lower strengths of MS CONTIN or other opioids.
Most patients given around-the-clock therapy with controlled-release opioids may need to have immediate-release medication available for exacerbations of pain or to prevent pain that occurs predictably during certain patient activities (including incident pain).
Continuation of Therapy
The intent of the titration period is to establish a patient-specific daily dose that will provide adequate analgesia with acceptable side effects and minimal rescue doses (2 or less) for as long as pain relief is necessary. Should pain recur, the dose can be increased to re-establish pain control as outlined above. During chronic, around-the-clock opioid therapy, especially for non-cancer pain syndromes, the continued need for around-the-clock opioid therapy should be reassessed periodically (e.g. every 6 to 12 months) as appropriate.
Cessation of Therapy
When the patient no longer requires therapy with MS CONTIN® tablets, doses should be tapered gradually to prevent signs and symptoms of withdrawal in the physically dependent patient.
Conversion from MS CONTIN to Parenteral Opioids
When converting a patient from MS CONTIN to parenteral opioids, it is best to assume that the parenteral to oral potency is high. NOTE THAT THIS IS THE CONVERSE OF THE STRATEGY USED WHEN THE DIRECTION OF CONVERSION IS FROM THE PARENTERAL TO ORAL FORMULATIONS. IN BOTH CASES, HOWEVER, THE AIM IS TO ESTIMATE THE NEW DOSE CONSERVATIVELY. For example, to estimate the required 24-hour dose of morphine for IM use, one could employ a conversion of 1 mg of morphine IM for every 6 mg of morphine as MS CONTIN. The IM 24-hour dose would have to be divided by six and administered on a q4h regimen. This approach is recommended because it is least likely to cause overdose.