Therapeutic uses of Amphetamine?
was widely prescribed until the mid 1960s as a stimulant
and appetite-suppressant, until the dependence-potential
of amphetamine (and other stimulants) led to a falling
out of favour among the medical profession. Amphetamine,
although a controlled drugs, is still prescribable
for certain conditions (e.g. narcolepsy), and appears
in Schedule 2 of the Misuse of Drug Regulations 1985,
meaning that it can be prescribed for medical treatment
subject to proper monitoring and reporting criteria.
is a powerful central nervous system stimulant drug,
used recreationally for the euphoriant effects, as
well as "functionally" to ward off fatigue
and increase energy and capacity for physical activity.
The effects of amphetamine are similar to those of
cocaine, both affecting the same neural systems, amphetamine
stimulates catecholamine release, and cocaine reduces
reuptake - expressed simply, if the level of alertness
were to be represented by the water level in a bath,
amphetamine would act by turning on the taps, whereas
cocaine would act by putting in the plug.
effects of amphetamine have been studied for over
a century, although since it became a controlled drug
in most countries of the world, opportunities for
research on the effects on humans have been limited.
and Pain Relief
Studies: Animal studies have consistently found
stimulant drugs such as amphetamine and cocaine may
cause analgesia (typically measured by the length
of time an animal takes to respond to a painful stimulus).
Natsuoka et al reported "analgesic actions ((of
amphetamines) involve the participation of endogenous
serotonin and endogenous opioid peptides" Furst
suggested a relationship between the stimulant neurotransmitter
systems and opiate analgesia. A Russian study suggests
the analgesic effects may be influenced by psychosocial
factors. Amphetamine was found to decrease depression
of swimming endurace in mice treated with opiates,
suggesting the (similar/synergistic) analgesic effects
may be differentiated from the (opposite/antagonistic)
psychoactive effects of the two drug types. As with
humans, tolerance to the analgesic effects of both
amphetamine and morphine are reported in mice.
Studies in rats have suggested amphetamine-like compounds
can induce analgesic (pain-killing) effects potentiating
the analgesic effects of opiates, and that analgesia
from amphetamine may be counteracted by dopamine antagonists
- Clarke et al concluded: "dopamine innervation
of the nucleus accumbens... plays a major role in
the analgesic effect of amphetamine" - or
by destroying the dopamine-producing cells in brain-stem
nuclei. However, earlier studies suggested noradrenaline
rather than dopamine to be the mediating neurotranmitter
for amphetamine enhancement of opiate analgesia, that
amphetamine analgesia did not involve endogenous opiates
such that "amphetamine possesses intrinsic
contrasting effects on alertness of opiates and amphetamines
have been widely-noted: Borisenko, studying behavioural
effects and pain relief from opiates and amphetamine,
reported "the analgetic action and that activating
the positive emotion were independent effects of the
psychotropic agents.". The reversal of narcotic-induced
depression by amphetamine was also noted by Malec
et al and Lakin Et al. Miksic et al considered there
to be two distinct neural mechanisms underlying the
effects of analgesia and euphoria.
et al considered in 1986 that "opiate analgesia
is potentiated by concomitant d-amphetamine administration.
The mechanisms involved in this potentiation warrant
further investigation for the clinical management
Studies: In 1979, Shimm et al studied pain management
in chronic cancer patients and concluded "Stimulants
such as cocaine and amphetamines both potentiate narcotic
analgesia and reduce narcotic-induced somnolence and
respiratory depression" A 1967 study found
the analgesic affect of aspirin to be modified by
healthy male volunteers, Webb et al found amphetamine
and a non-opiate analgesic both increased pain thresholds,
the combination providing the greatest relief.
et al found the combination of amphetamine and morphine
to create greater euphoria among substance-abuser
than either drug alone, although the psychological
effects (stimulation, drowsiness) were mutually attenuated,
considering there to be a greater degree of abuse
potential from the combination of the two drugs.
a treatise on cancer pain, Mancini et al reported:
"Many drugs, such as nonsteroidal antiinflammatory
agents, tricyclic antidepressants, corticosteroids,
benzodiazepines, amphetamines, antiemetics, oral local
anesthetics and bisphosphonates have been suggested
to have adjuvant analgesic effects."
et al commented: "Studies with human subjects
have confirmed the enhancement of opioid analgesia
by amphetamines and, in addition, have demonstrated
that psychostimulant drugs produce a decrease in somnolence
and an increase in general cognitive abilities. The
greater cognitive alertness, moreover, allows the
use of larger opioid doses, which can produce a substantial
increase in analgesia."
et al observed: "amphetamines... have been
rarely used in the past, but have been recently introduced
in the palliative treatment in oncology. They have
stimulating, antidepressive and perhaps coanalgesic
effects. They can alleviate sleepiness related to
opiates analgesics which are given in chronic pain."
study of female migraine patients found they were
significantly more likely than controls to be using
amphetamine, although the authors did not indicate
whether this was considered a causative factor or
an attempt at self-medication.
a clinical study of cancer patients in Bristol, O"Neill
concluded: "Adjuvant analgesic drugs and non-drug
measures should be used whenever possible, and drugs
should be chosen that will not contribute to existing
difficulties. The appropriate use of psychostimulants
has yet to be established..."
and Intestinal function.
boosts the sympathetic (autonomic) nervous system
in a similar way to adrenaline, affecting many areas
of the bodily functions in addition to psychoactive
and central nervous system effects. Increased sympathetic
activity reduces gut motility, whereas parasympathetic
activity increases it.
and amphetamine-regulated transcript peptides (CART)
are found in areas of the intestines, and are thought
to be responsible for regulating the sympathetic nervous
system effects. Amphetamine has been shown to block
stimulation of intestinal activity by some neurotransmitters,
but not others: "d-amphetamine may act as
an antagonist to TRH without influencing the movement
of calcium ions in smooth muscle or muscarinic receptors
and that contractile responses to TRH-A are mediated
through TRH receptors in the myenteric cholinergic
et al reported a case history of ischaemic colitis
associated with use of oral (dextro)-amphetamine and
other sympathomimetic agents, causing abdominal pain
and rectal bleeding. A 1972 Polish study examined
the effects of chronic amphetamine exposure on the
digestive tract in rats. It has not been possible
to obtain a translated copy, or further details, of
this study at the present time.
- Amphetamine as Medcine
It is well-established within the scientific literature
that amphetamine can provide an analgesic (pain killing)
effect in its own right, and enhance the analgesic
effects of opiate painkillers (e.g. morphine, codeine).
developments in the treatment of the terminally ill
suggests amphetamines may have a role to play in the
management of severe pain as an adjunctive therapy,
by enhancing the effects of opiates. However, this
role is limited in long-term use by the high degree
of tolerance and dependence which frequently develops
with prolonged stimulant use.
are likely to cause drowsiness, reduced alertness
and impaired cognitive function - effects which are
reduced or reversed by amphetamine. The risk of respiratory
depression with high doses of opiates is also reduced
with amphetamine, allowing larger doses pain-relief.
analgesic role of stimulant drugs is thought to mimic
the effects during stress, where pain (e.g. from an
injury) is not experienced during crises such as armed
combat or other potentially life-threatening events
(such effects are even reported in sporting contests).
Tract: Amphetamine may reduce the symtoms of gastrointestinal
disturbance by reducing motility of the gut.
is insufficient evidence to determine whether or not
amphetamine may directly benefit coeliac disease,
or whether it may exacerbate the condition. No such
studies have been published in medical or scientific
journals over the past 25 years.