Simultaneous Use of Stimulants and Opioids
It’s a puzzling situation. History and science are pretty clear: the simultaneous use of stimulants and opioids have, for over a century, been reported to be a superior combination for pain relief. 1 So, based on history, why isn’t every patient who’s taking opioids also taking a stimulant? For example, in 1977 the renowned analgesic researcher, William Forest, led a national cooperative study which clearly showed that a dose of dextroamphetamine with morphine increased morphine’s pain-relieving potency one and a half to two times. 2 Forest and colleagues posited that the great therapeutic benefit of the combination of dextroamphetamine and morphine wasn’t widely used because, “We suspect that the combination has not been accepted clinically at least, in part, because physicians do not want to subject their patients to the risk of abuse if these drugs (dextroamphetamine and morphine) are used.”
Although these pioneering researchers lamented the non-use of this combination in their seminal study, it turns out that they may, after all, get their wish. Sophisticated pain practitioners everywhere are starting to use various combinations of stimulants and opioids to enhance their pain therapeutics. What’s more, all parties concerned—including those who foot the bill—are benefitting.
An Old History of Use and Effectiveness
It has been long-established that amphetamines and other stimulants have an analgesic effect in their own right and significantly enhance the analgesic effects of opioids. 1-9 The first person to suggest this combination was probably Dr. Herbert Snow of London (in 1896) who recommended an oral mixture of morphine and cocaine for patients suffering in agony from an advanced disease. 1 In the 1920s, the “Brompton Cocktail” was invented at the Royal Brompton Hospital in London. 1 The cocktail consisted of morphine or diacetylmorphine (heroin), cocaine, ethyl alcohol, and chlorpromazine (e.g., Thorazine ® ) for nausea. It was usually reserved for terminally ill patients with cancer or tuberculosis. Dextroamphetamine and morphine were found to be an excellent combination for pain relief during World War II. 3 Also, during this war-time period, it was found that stimulants would counteract the respiratory depression and sedation of opioids. 4,5 Although the use of this combination was known, it was seldom used clinically and essentially unreported in the medical literature after the war. Instead, researchers, commercial producers, and practitioners turned their attention to combining stimulants, including caffeine, into single commercial products. 6-8 This interest led to the development of popular combination drugs consisting of weak stimulants with opioids and/or inflammatory agents. The combination products of codeine with aspirin or acetaminophen and caffeine are widely known and have been highly prescribed for over two generations.
Although not yet widely adopted, a number of excellent studies on stimulants and opioids were done between 1950 and the end of the last century. 10-16 All of these studies—whether done in animals or humans—showed remarkable enhancement of pain relief when stimulants were combined with opioids. 8-14 One of the surprising and positive finding in these studies was that stimulants not only gave better pain relief but subjects (animals and humans) routinely performed mentally and physically better and had less respiratory depression and sedation than with opioids alone. 15-19 Clinical studies outside the seminal study by Forrest et al 2 are sparse but those that have been reported show the significant advantage of the simultaneous use of opioids and stimulants. 10,17 Even obstetrical analgesia is enhanced by this combination. 20
Why a Need for Stimulants?
The “Decade of Pain” has brought opioids to the forefront of chronic pain treatment. It is estimated that about 10 million patients in the United States now use them. The exposure of millions to opioids has given us a population of patients who now know that the opioid class of drugs is indispensable for their pain relief. Although hardly news, practitioners, patients, and families are now beginning to observe the complications of opioids including sedation, fatigue, mental dullness, constipation, falls, and hormone suppression. Since no caring practitioner or patient who experiences pain relief with opioids is about to give them up, a stimulant added to the opioid regimen can enhance pain relief, limit opioid dosage, and prevent some opioid complications.
Mechanism Of Action
Too often it is perceived that the endogenous endorphin-opioid receptor system is the only pain control mechanism in the central nervous system. 21,22 In reality, multiple neurochemical systems are at play in pain relief. 22 They include, among others, the serotonergic, gamma-amino-butyric acid (GABA-ergenic), and adrenergic (norepinephrine-dopamine)systems. 8,21-23 Pain relief with stimulants appears to be primarily mediated by norepinephrine and not dopamine. 23 It is the simultaneous triggering of the endorphin and adrenergic neurochemical systems that gives the combined administration of opioids and stimulants a pain-relieving effect much greater than either one alone. 8,13,17
When a chronic pain patient on opioids adds a stimulant to their regimen, they and their observing family usually note less fatigue and lethargy and accompanied by intellectual awakening and more energy. Patients will frequently report less depression, better memory and more intense concentration ability (see Table 1). Enhanced pain relief may occur with the first dosage of stimulant. Stimulants can also lower an opioid daily dosage and ease the discomfort of opioid rotation or forced withdrawal due to loss of financial support of an expensive opioid.
How To Administer
Stimulants generally fit a dose response curve. They are not effective until the dosage reaches a specific level for a patient’s specific need. For safety, start with a low dosage and titrate upward over four to eight weeks until a therapeutic effect is reached. Stimulants can be given on their own fixed schedule such as two or three times a day or they can be simultaneously given with an opioid dosage. Table 2 presents several tips on how to administer stimulants.