Combinational drug therapy has been used for years as a mechanism for either pharmacologically addressing conditions presenting multiple symptoms, or for providing greater relief of a single symptom without overdose. One classic example of combinational therapy for addressing multiple symptoms can be found in many over-the-counter cold and flu medicines. Such medicines often combine a nasal decongestant, such as pseudoephedrine with a cough suppressant, such as dextromethorphan HBr, and an analgesic/antipyretic agent, such as acetaminophen.
Pain is one example of a single symptom that can be treated with combinational therapy in order to avoid overdose or to at least minimize the total dose of a single analgesic agent and thereby potentially avoid or reduce adverse effects. Acute pain, often the result of a traumatic event, can be effectively treated with doses of short acting analgesics, such as opioids. Chronic pain, however, because of its occurrence frequency and/or sustained presence, requires either multiple daily doses of short acting analgesics, or longer acting analgesic formulations in order to obtain effective management.
Long acting or “sustained release” formulations have in fact, been found to be desirable in treating many chronic conditions, such as chronic pain, that would otherwise require inconvenient multiple daily doses. However, oral dosage sustained release formulations are often complicated in their design, and while effective for many single drug therapies, may present a number of challenges when attempting to formulate combinational drug therapy.
As a result, sustained release formulations that are simple in design and construction that can effectively accommodate multiple active agents in a stable manner, and which can provide effective combination drug therapy over sustained periods continue to be sought.