Considerations about Prescribing Adult Doses of Stimulants for Adults
The highest dose of stimulants approved by the FDA (US Food and Drug Administration) for children is 60 mg per day. The FDA has established no upper dose limit for adults. That does not mean there is no limit to the dose adults can take. It just means that the pharmaceutical companies that produce these medications have not submitted safety studies to the FDA for approval. Dosage limits for adults have been developed by practicing clinicians, but in the absence of a ruling from an accepted governing organization, there is no universally agreed upon maximum treatment dose for adults.
Many clinicians who are not familiar with the effects of the stimulants (or the FDA position) restrict their prescriptions to the FDA’s maximum children dose. Others set maximum doses somewhat higher. There is relatively little information published in the scientific literature about the effects of higher doses on adults seen in typical adult ADD clinic or practice.
There are a number of reasons why the average and maximum doses for adults might be higher than those of children.
- on average, adults weigh more than children, and dosing is, in part, weight related
- adults need treatment coverage for more hours per day than do children as their work days are longer, they often have family or other responsibilities in the evening, and they stay awake later in the evening
- clinical experience has shown that optimal doses required for adults are higher than those required for children
Nonetheless, there is enough concern among professionals who don’t have much experience treating adult ADD about prescribing higher-than-child doses that a number of issues should be considered before prescribing such doses.
Might a higher dose pose a health problem for the patient?
May the patient be feigning a need for higher doses in order to obtain stimulants to distribute.
Might the patient be abusing their medication?
What if the patient discovers on his own that a higher dose of medication is more helpful?
Might prescribing a higher dose trigger an inquiry from the Drug Enforcement Administration?
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Might a higher dose pose a health or welfare problem for the patient?
It seems generally true that in any individual patient a higher dose is more likely to induce side effects that a lower dose. However, there is great variability among patients in the dose required to cause side effects. This can be understood in terms of the ratio of the adrenalin-like effects of the stimulants on the mind and on the body. In the best of circumstances the effect on the body is minimal and that on the brain sufficient to be effective. But not infrequently patients have a reverse ratio and experience a preponderance of adrenalin-like side effects with minimal or no beneficial cognitive effects. I have seen many patients who develop side effects like increased heart rate or sleeplessness on what might seem to be a very low dose (e.g. 2.5 mg of amphetamine) while others seem impervious to side effects at high doses (e.g. 160 mg per day of amphetamine). This being true, all things being equal, it seems best to follow the standard procedure of starting treatment with a low dose and increasing it slowly within the limits of tolerance until an effective dose is achieved.
The more serious adverse effects of stimulants are paranoia and rare fatal cardiac events. In patients with a previous history, they may activate seizures, psychosis, and bipolar symptoms. Other reported adverse effects are aggression and visual disturbances.
In my experience, paranoia has occurred at both usual and high dose levels (from 40 mg per day to 180 mg per day). I do not known whether paranoia is dose related, but in the absence of evidence to the contrary, it is probably best to assume that it is. In my experience, a small number of patients taking low dose levels for a relatively short period of time required hospitalization for their paranoia. In a few of these cases, stimulant induced sleeplessness seemed to be a factor in precipitating the paranoia. One patient taking 180 mg per day became suspicious of her husband’s fidelity for a number of months. When couple’s therapy suggested that there was no real basis for her suspicions, her dose of amphetamines was reduced to 160 mg per day, and the suspicions disappeared.
Adverse cardiac events have occurred largely among patients with known or occult cardiac disorders that usually involve structural abnormalities or conduction defects. Many of these were diagnosed only post-mortem. To minimize the likelihood of such effects, clinicians should ask about a family history of early cardiac death among blood relatives, as these cardiac conditions may be hereditary. Higher doses are probably more risky in those over 55 years of age or so, and these patients deserve to have a cardiac exam including an EKG before starting stimulants. All patients should be informed of the possibility of death from cardiac complications before starting stimulants. (I have been surprised that no patients of mine have refused treatment after being told this. Perhaps they have been inured to such warning by television advertisements about other medications.) For self protection, clinicians may want to have their patients, especially older patients, sign an informed consent statement acknowledging and accepting the risks that were discussed with them.
Historically, care has been taken in prescribing stimulants when there is a history of bipolar disorder because of the fear they may exacerbate manic symptoms. Some bipolar patients will become manic whether or not they are taking stimulants. When they are taking stimulants and become manic, stimulants may be blamed for the episode though the association may be coincidental. There is little if any evidence from controlled studies that stimulants do precipitate manic episodes and a few studies that suggest they do not. Nonetheless, caution is warranted when considering prescribing stimulants for bipolar patients; many clinicians prescribe mood stabilizers for bipolar patients before starting stimulants though there is no clear research evidence to my knowledge supporting this as a standard practice, and the mood stabilizers carry risks of their own.
May the patient be feigning a need for higher doses in order to obtain stimulants to distribute?
This is a particularly thorny problem when prescribing for students. I know of no way to determine whether a patient may be diverting his medication and have been fooled a few times by “good” patients who were taking usual doses of stimulants and giving them away or selling them. (On the other hand, I always harbored a suspicion that two of my patients who were taking around 200 mg per day of stimulants may have been diverting them. Both were in somewhat difficult financial straits, both were slightly eccentric. I was relieved when circumstances required both of them to transfer their treatment elsewhere.)
The problem faced by clinicians is that they usually must rely almost solely on the patient’s report of the effects of the medication at different doses. It can be difficult to tell a patient who has taken a higher dose than you prescribed and swears that only the higher dose works that the dose must be reduced. I have received plaintive email notes to this web site from a number of people throughout the country who found on their own that only a higher dose worked for them but were rebuffed by their prescribing clinician when they asked for a prescription for that dose. Many of these patients reported taking what they experience as a helpful dose half the month and going without for the rest of the month. I believed their stories, particularly since none of them asked me to prescribe for them.
Might the patient be abusing their medication?
In my experience in a private practice, this has occurred to my knowledge only among students who were using the medication to study or party into the night. I have not found these patients request higher doses. More often they just don’t take their medications when they don’t think they need them and use them to excess when they want to. I don’t know how to avoid this. There are other practice setting where abuse may be a common problem, but I would guess that most patients who abuse their medication get them illicitly or by going to multiple clinicians, or by claiming falsely that they have lost their supply of medications.
If a patient does have a serious adverse effect from taking a higher dose, may it put the clinician at risk for a malpractice suit?
While this risk is reduced if an informed consent discussion has been held and documented, a suit could be brought even if this discussion was documented. As community and national practice standards have increasingly supported doses in adults than are higher than the FDA approved children’s dose levels, clinicians have more support than in the past for using such doses. However, it is still not established what the limits of acceptably high doses are. Any clinician who has concerns about this issue should probably consult with colleagues who are experienced in treating ADD and with his or her malpractice carrier for counsel on this topic.
Might the Drug Enforcement Agency question a clinician’s prescribing practices if he prescribed higher doses?
I am not an expert in this area but do have some personal experience. I received a call from the DEA about a prescription for a patient who was taking 180 mg per day of stimulants. The agency had been called by the patient’s pharmacist who was concerned that the dose was greatly over the 60 mg per day maximum for children noted in the PDR. I explained to the agent that prescribing such doses was not my usual practice but that I did so with a certain portion patients whom I thought required it. I described the literature that suggested higher doses are usually needed by adults and by people who need coverage for 14 hours a day or so. The agent was satisfied with my explanation, and I never heard from the DEA again.
If you are a clinician with other thoughts about, or experiences with, prescribing “high” doses, please feel free to contact me at MarcDSchwartzMD@GMail.com
What if the patient discovers on his own that a higher dose of medication is more helpful?
One dosing problem faced by clinicians is that they must rely almost solely on the patient’s report of the effects of the medication at different doses in orfder to determine an optimal dose. It can be difficult to tell a patient who has taken a higher dose than you prescribed and that he tells you is the dose that really works for him to reduce it. I regularly receive plaintive emails from people throughout the country who found on their own that a higher dose worked for them but were rebuffed by their prescribing clinician when they asked for a prescription for that dose. (Since there would be no benefit in their midsleading me about this issue, I assume they were telling me the truth.) Many of these patients reported taking what they experience as a helpful dose half the month and going without for the rest of the month.
Clinicians are faced with the dilemma that they may be depriving some patients of the benefit of the stimulants in order to prevent others from diverting or abusing them. There are many views of how to deal with this issue, but mine is to err on the side of helping patients while remaining alert to the possibility that I may be fooled by a small minority who are diverting their medications.
Might prescribing a high dose pose legal problems for the clinician?
The FDA has set certain limits on what is an approved level of stimulant medication dosing for children. It has not set any upper limit for adults as no studies were submitted to it by pharmaceutical companies seeking approval for the use of stimulants with adults. I examine this issue at some length on the Dosing page of this site. Here I will restrict myself to the concerns clinicians might have about the consequences on their practice for prescribing higher doses than those approved by the FDA for children.
If a patient does have a serious adverse effect from taking what is regarded as some as a high dose of stimulants, it may put the clinician at risk for a malpractice suit. While this risk is greater if no informed consent discussion has been held and documented, a suit might be brought even if this discussion was documented. As community and national practice standards have increasingly supported doses in adults that are higher than the FDA approved children’s dose levels, the clinician has more support than in the past for using such doses. However, it is still not established what the limits of acceptably high doses are. Any clinician who has concerns about this should probably consult with his or her malpractice carrier for counsel on this topic.
Clinicians may be concerned that the Drug Enforcement Agency may question their prescribing practices if they use higher doses. I am not an expert in this area but do have some personal experience. I received a call from the DEA about a prescription for a patient who was taking 180 mg per day of stimulants. The Agency had been called by the patient’s pharmacist who was concerned that the dose was greatly over the 60 mg per day maximum noted in the PDR. I explained to the agent that prescribing such doses was not my usual practice but that I did so in a small percent of patients whom I thought required it. I described the literature that suggested higher doses are usually needed by adults and by people who need coverage for 14 hours a day or so. The agent was satisfied with my explanation, and I never heard from the DEA again.
