Researchers have discovered that modafinil, despite having been approved by the Food and Drug Administration as a drug to promote wakefulness, does raise blood pressure.
Modafinil is used in the treatment of hypersomnolence, such as in narcolepsy and in sleep apnea.
In order to determine whether or not there were any side effects of modafinil, researchers at the University of California San Diego studied six healthy subjects who took 200mg doses of modafinil daily for 21 days.
These subjects were monitored before they took the drug as well as during and after their regimen was completed.
After they had finished their regimen, researchers found that there was a significant increase in blood pressure among those who had taken modafinil compared to when they had taken a placebo pill.
The short-term increase ranged from 6% to 17%, during which time systolic blood pressure increased by 10mmHg. It should be noted that some individuals also experienced an increase in heart rate while on the drug, but it was not drastic enough for them to be considered clinically meaningful.
How It Affects The Body
Researchers state that they are not entirely sure how modafinil works and that is why they tested it on healthy subjects.
The drug is believed to work by increasing the amount of orexin in the brain, which helps stimulate wakefulness.
Researchers used an fMRI to track what happens in the brain when a person has a working memory task, such as counting backwards from 100 by 7s while looking at a screen displaying random numbers.
The results showed that there was a significant increase in activity in the prefrontal cortex among those who had been given modafinil compared to those who had taken placebo.
Mechanism of Action
Researchers believe that modafinil works like amphetamine or cocaine by increasing levels of the neurotransmitter norepinephrine in the brain.
They state that this would reduce the amount of alertness-related inhibition and allow a person to accomplish more tasks in less time.
However, they believe that there are important differences between modafinil and amphetamines or cocaine, which is why they tested it on healthy individuals.
Researchers say that there were no serious side effects in this study. However, they did note that 1 of the subjects had to discontinue treatment because of a headache. They also noted that some individuals experienced what they described as "dysregulation of mood."
They believe that this may be attributed to modafinil interacting with the neurotransmitter serotonin, which is why there were significant changes in mood, although it was not severe enough for them to give it a formal designation.
The researchers say that future studies should include larger groups of people who take modafinil and should be conducted over longer periods of time.
They also state that more research should be done on the drug's effects on blood pressure and its use by those who do not have a history of sleep apnea or insomnia.
Men and Women Differ In Effects Of Modafinil
It has also been known that women respond differently than men do when taking modafinil. Women experienced greater improvements of executive functioning, working memory and spatial planning than men did.
Additionally, women had higher increases in blood pressure after taking modafinil compared to men.
The researchers believe this could be attributed to women having naturally lower levels of orexin in their brains than men do. Women were also less likely than men to experience increases in heart rate after taking modafinil.
According to the researchers, these differences in the responses of women and men could account for some of the higher risks of cardiovascular problems seen among female patients who were using modafinil.
Private Practice Doctors Still Recommend Modafinil
Although it is possible that more research needs to be done on this subject, private practice doctors have not been put off by these findings.
However, they do recommend that people should still take modafinil only as prescribed by their doctors.
It is also recommended that those who are on it should continue eating healthy diets and exercising regularly to help control their blood pressure while taking it.
They also encourage anyone who takes blood pressure medication to make sure their doctor knows they are taking modafinil, so they can adjust their dosages accordingly if necessary.
A study published in February 2011 found that although modafinil is generally well tolerated, it can cause side effects such as headaches and insomnia, which can limit its use.
In addition, although modafinil may help many patients deal with sleepiness problems, some people may not be able to tolerate it.
In terms of its effects, researchers found that modafinil can cause an increase in blood pressure and heart rate.
However, this increase was not considered significant aside from the possibility of causing headaches and other side effects that can affect a person's quality of life.
The researchers conclude by recommending larger studies and more safety considerations of modafinil before it is recommended for widespread use.
- https://pubmed.ncbi.nlm.nih.gov/18548832/ (Effect of modafinil on cerebral blood flow in narcolepsy patients)
- https://pubmed.ncbi.nlm.nih.gov/18275558/ (Cerebral blood flow changes in man by wake-promoting drug, modafinil: a randomized double blind study)
- https://pubmed.ncbi.nlm.nih.gov/10096265/ (Does short-term treatment with modafinil affect blood pressure in patients with obstructive sleep apnea?)