From the times of Aristotle, “what came first: the chicken or the egg?” was one of the regular questions in the question file. Scientists have now concluded that the egg came first. Similarly, talking about dopamine makes more sense than introducing dopaminergic drugs right off, since dopamine came first.
Dopamine, a popular chemical in regards to neuroscience, is the central driver for all the functions that your brain performs. Without dopamine, we would all be less of a human and more of some un-human creature. Researchers are continually looking for ways how things work inside the human body and how things interact to create human behaviors. Dopamine has answered many of such questions for them.
It may sound crazy, but from your dreams to the biggest secrets you have, dopamine is involved in almost everything. Talk about learning, love, motivation, pleasure, attention, behavior, movement, sleep, addiction, and even spirituality, and you’ll see dopamine in the discussion.
In one sentence, dopamine is the neurotransmitter (or chemical, if you like) that helps in sending signals across the brain.
What are dopaminergic drugs?
These are pharmaceutical substances that influence the levels and functions of dopamine. The deficiency or excess of dopamine can cause health problems, such as Parkinson’s disease (a movement disorder) and schizophrenia (a psychiatric disorder), respectively.
Dopaminergic drugs are used when problems related to dopamine arise. This article will take you through four dopaminergic drugs that agonize the effects of dopamine and three drugs that antagonize it. But let’s first talk about how a change in dopamine levels affects your health.
10 ways dopamine affects your health
Absence or deficiency of dopamine can wreak havoc in the body. Research has discovered dopamine problems in various conditions, such as Alzheimer’s, Parkinson’s, binge eating, addiction, Attention Deficit Hyperactivity Disorder (ADHD), depression, schizophrenia, bipolar disorders, and gambling. Moreover, at the developmental stage, lack of dopamine can result in mental retardation.
Low sex drive
Dopamine has a marked effect on the modulation of sex drives via multiple mechanisms. Loss of libido and reduced desires for sexual activity are linked to dopamine deficiency – loss of libido is a sexual dysfunction characterized by lack of sexual desire despite the presence of a sexual stimulant.
Through various studies, it is found that desensitization to dopamine or low dopamine levels is the frequent cause of reduced sex drive in humans. Specific areas in the brain release dopamine when a man anticipates sex. In the absence of dopamine, there is no way to communicate this message to the brain. In contrast, when dopamine is released, it sends a signal to the brain which in turn activates sexual motivation.
No dopamine = NO libido, NO desire, and NO aggression.
Erectile dysfunction
In the act of penile erection, dopamine is the first chemical to set off a series of important chemical interactions leading to an erection. Be it libido or erection, dopamine is an all-important neurotransmitter to control sexual function, according to research.
Restless leg syndrome
As you might have assumed from its name, restless leg syndrome (RLS) is particularly depicted by the strong desire to move legs. This sort of urge arises especially at rest and is completely or partially relieved by some movement. Symptoms are at peak during the night which makes quality sleep impossible.
RLS is mainly caused by the deficiency of dopamine. Individuals have seen a marked improvement in their symptoms upon taking dopamine agonists. Similarly, various drugs that block the dopamine pathway produce symptoms of RLS. Now you can easily establish a conclusion, i.e., accurate dopamine levels can prevent and treat restless leg syndrome.
Attention-deficit hyperactivity disorder – ADHD
Attention deficit hyperactivity disorder (ADHD) is a brain disorder. Individuals with ADHD have difficulty paying attention for longer periods or may have episodes of hyperactivity, both of which interfere with their daily life. It is sometimes referred to as attention deficit disorder (ADD), but ADHD is medically accepted term.
Many studies have found that a commonly involved neurotransmitter in ADHD is dopamine. Like I said before, dopamine contributes to attention and focus. Moreover, impulsive and behavioral problems have also shown to have links with dopamine deficiency.
Narcolepsy
You might have come across some people who sleep anywhere at any time of the day, no matter whatever activity is going on. These individuals do not intentionally nod off in the middle of a conversation. It’s a proper medical condition – a neurological disorder termed as narcolepsy. Narcolepsy is characterized by excessive daytime sleepiness, uncontrollable sleep episodes, cataplexy (sudden loss of muscle tone), hallucinations (delusional experiences), and sleep paralysis resulting in a brief inability to speak or move while trying to sleep or waking up.
Other symptoms include loss of posture and difficulty in waking up. The chemicals that trigger sleepiness and cataplexy in this disorder are still unknown. One of the main reasons for human narcolepsy is hypocretin/orexin neurons deficiency, but various irregularities in dopaminergic neurotransmission also contribute to displaying the symptoms.
Irritability and aggression
Dysregulation of the dopamine system is linked to irritability and aggression. Feelings of anger and a frequent feeling of being deprived of energy along with lack of motivation to do anything that requires physical and mental effort is a typical presentation of irritability and aggression. These two correlates closely with each other and usually occur together.
Psychosis
Psychosis is an abnormal mental state that results from complex mechanisms, but broadly speaking, symptoms occur when there is dysregulation of dopamine and its role in the brain.
Individuals with psychosis have difficulties telling between reality and otherwise. Symptoms include one or more of the following:
- False beliefs
- Seeing things that are not there
- Hearing voices that others cannot hear
Anxiety
Well-documented studies have implicated dopamine, serotonin, and norepinephrine in the pathogenesis of anxiety. Researchers believe that the severity of anxiety is linked to dopaminergic dysregulation in response to social stress.
Depression
Motivation, activity, focus, and pleasure are all regulated in part by dopaminergic responses and impairment of these four characteristics are prominently observed in depression. Although the pathophysiology of depression has been studied in greater detail in terms of other chemicals like serotonin and norepinephrine, research now suggests dopaminergic dysregulation as a contributing factor in depression.
Exhaustion and fatigue
Dopamine dysregulation also plays a role in fatigue and exhaustion.
How dopaminergic drugs work?
It’s always good to know the phenomena behind actions and effects of things. But you might wonder why use dopaminergic drugs when we can give dopamine to the patient?
It is because dopamine cannot cross the blood-brain barrier. No, it’s not another complicated concept from the world of neurophysiology. It is simply a barrier that separates your brain and its surrounding fluid (cerebrospinal fluid) from blood for protection sake. Contrary to dopamine, dopaminergic drugs can cross this blood-brain barrier and produce desired results.
Dopamine agonists
Agonists are the synergists that enhance the function of a neurotransmitter/chemical either by acting in its place or by increasing sensitivity of receptors towards that chemical. Dopamine agonists mimic dopamine. They bind to the dopamine receptors and activate them. Receptor activation, in turn, provides relief from problems with balance and movement control.
Dopamine antagonists
Contrary to agonists, antagonists have the opposite effect. They bind to the receptors and block them. Dopamine antagonists are the pharmaceutical chemicals that block the dopamine receptors and prevent their activation from dopamine.
Dopamine agonists
Drugs that increase dopamine levels
Pramipexole (Brands: Miramax, Mirapexin, and Sifrol)
Various brands of this drug are used to treat Parkinson’s disease and restless legs syndrome. It works in place of dopamine and improves bodily movements. Pramipexole has the same effects as of dopamine.
Side effects
You know well how various medicines can cause side effects. Most probably, you have already experienced a few of these effects. While some drugs may produce simple side effects such as constipation, nausea, and dry mouth, others will make you sleepy or insomniac. Drugs might also force you to run to the bathroom every few minutes.
The list of side effects goes on and on. But let’s find out about the side effects of Pramipexole.
The more common side effects include orthostatic hypotension (lightheadedness and feeling dizzy when standing from sitting or lying position), drowsiness, sleep issues, nausea, weakness, hallucinations, and unusual body movements like twitching and twisting. Of the less common side effects are dysphagia (swallowing difficulty), cough, changes in vision, confusion, bouts of sleepiness, frequent urination, troubled breathing, and fever.
Rare side effects may include chest pain, swelling of body parts, bloody urine, loss of bladder control, abnormal thinking, and anxiety. Should any of these side effects occur it’s recommended to get in contact with your doctor.
Pramipexole dosage
This drug is started at a low dose of 0.125 mg given three times daily. Based upon the clinical results and patient’s response the dose is adjusted to a higher side. After some time, the patients are put on the maintenance dose which is 1.5 to 4.5 mg in the case of Parkinson’s disease.
Reviews of Pramipexole
On WebMD website, it is rated an average of 4.03 out of 5 stars for effectiveness, with a total of 80 reviews.
Another review:
Ropinirole (Brands: Requip, Requip XL, and Repreve)
This drug is also used to treat Parkinson’s disease and restless legs syndrome. It mimics the action of dopamine and provides the much-needed effects of controlled movements.
Side effects of Ropinirole
Just like pramipexole, ropinirole has some side effects. They range from as simple as nausea, vomiting, and constipation to complex issues like movement difficulties and chest pain.
Typical symptoms are as follows:
- Drowsiness
- Dizziness
- A headache
- Dry mouth
- Excess sweating
- Nausea
- Vomiting
- Constipation
Patients may also experience a sudden drop in blood pressure resulting in dizziness and fainting. To prevent such fainting episodes, do not get up fast from a sitting or lying position. Drop in blood pressure is more likely when the medicine is first started or the dose is increased. It improves after some time. Serious side effects of ropinirole include mental changes, muscle spasms, swelling of the feet, fast or slow heartbeat, visual disturbances, and strong urges, such as high sex drive or increased gambling.
But here’s the good news. You don’t have to worry much because not every patient experiences these side effects. But since some report them, it is mandatory to mention these effects and give patients a heads up so they can monitor for any bad signs.
Ropinirole dosage
This drug is started at a low dose and based upon the clinical results and patient’s response the dose is adjusted to a higher side. The typical dosage for the treatment of Parkinson disease is 1 to 2 mg given three times a day. It may be given in combination with other drugs like levodopa or carbidopa. For the treatment of restless legs syndrome, ropinirole is specifically given 1 to 3 hours before bedtime (0.25 mg). The dose is slowly increased keeping in view the clinical response and tolerance.
Reviews of Ropinirole
On WebMD website, it’s rated an average of 3.50 out of 5 stars for effectiveness, with a total of 206 reviews.
Another review:
Bromocriptine (Brands: Parlodel and Cycloset)
Bromocriptine is a dopamine receptor agonist. It is used to treat hyperprolactinemia – a condition in which there is an excess of prolactin hormone. The excess level of this hormone results in infertility, lack of menstruation, and nipple discharge. But that’s not it.
Bromocriptine is also used to treat other conditions like acromegaly (too much growth hormone), Parkinson’s disease, and to control blood sugar levels in type 2 diabetes.
Side effects of Bromocriptine
The usual side effects of bromocriptine are lightheadedness and nausea. Less common effects reported mainly in patients with Parkinson’s disease include the following:
- Hallucinations
- Uncontrolled body movements
- Confusion
Bromocriptine dosage
For Parkinson’s disease, this drug is started at a low dose and then gradually increased based on the clinical results and patient’s response. The typical dosage for the treatment of Parkinson disease is 10 to 40 mg per day. It may be given in combination with other drugs like levodopa or carbidopa.
Reviews of Bromocriptine
On WebMD website, it’s rated an average of 3.39 out of 5 stars for effectiveness, with a total of 58 reviews.
Another review:
A third review:
Cabergoline (Brands: Dostinex and Cabaser)
This dopamine receptor agonist decreases prolactin release from the pituitary gland. Like bromocriptine, cabergoline is also used to treat hyperprolactinemia.
Side effects of Cabergoline
Although it is useful in the treatment of hyperprolactinemia, cabergoline does cause some unwanted effects.
Bloating, swelling of various body parts, itching, prickling, numbness, or tingling sensation in feet, cold sweats, chills, weight gain/loss, fast heartbeat, dizziness, and confusion are among the less common side effects of cabergoline. Seek immediate help if you notice any of these symptoms.
Cabergoline dosage
Cabergoline is not a drug to be used daily. It is taken twice weekly for 6 months. The usual dose is 0.25 mg. The maximum safe dose is 1 mg taken twice a week.
Reviews of Cabergoline
On WebMD website, it’s rated an average of 4.04 out of 5 stars for effectiveness, with a total of 80 reviews.
Another review:
Dopamine antagonists
Drugs that decrease dopamine levels
Chlorpromazine (Brands: Thorazine and Largactil)
Chlorpromazine belongs to a group of antipsychotic medications known as phenothiazines. It is used in the treatment of schizophrenia, bipolar disorders, and manic depression.
Chlorpromazine is also used to treat pre-operative anxiety, nausea, and vomiting. You will also find its use in treating chronic hiccups, tetanus, and acute intermittent porphyria (a genetic metabolic disorder). It helps to reduce nervousness, aggressive behavior, and hallucinations.
Side effects of Chlorpromazine
Common side effects of chlorpromazine include nausea, lightheadedness, dizziness, tiredness, constipation, sleep disturbances, weight gain, and dry mouth. While taking this medicine, you may be at an increased risk of falling. Get up slowly from sitting or lying position to prevent falling episodes.
Stop using the drug, and call for medical help if you experience any of these serious side effects:
- Muscle stiffness and spasms
- Anxiety and agitation
- Difficulty in swallowing
- Sudden weakness/numbness on one side of the body
- Mask-like facial expression
- Tremors
- Uncontrollable movements like mouth puckering
- Restlessness
- A butterfly-shaped rash on face
- Joint pain
- Feeling hot or cold
Chlorpromazine dosage
Chlorpromazine is available as tablets, extended-release capsules, and syrup. The following dosage forms of asenapine are available:
- 10 mg
- 25 mg
- 50 mg
- 100 mg
- 200 mg
- 300 mg
The maintenance dose can be anywhere between 100 to 200 mg and is given once daily.
Reviews of Chlorpromazine
On WebMD website, chlorpromazine has rated an average rating of 4.38 out of 5 stars for effectiveness, with a total of 34 reviews.
Another review:
Asenapine (Brands: Saphris and Sycrest)
Asenapine is an antipsychotic medication that changes the action of certain chemicals in the brain. It is typically used for treating psychiatric disorders like schizophrenia and bipolar I disorder.
Side effects of Asenapine
Common side effects of asenapine include dizziness, feeling restless, tingling around the mouth, constipation, diarrhea, sleep disturbances, weight gain, and dry mouth.
Stop using the drug, and call for medical help if you experience any of these severe side effects:
- Allergic reaction (breathing difficulty, hives, and swelling on face, lips, tongue, or throat).
- High fever
- Uneven heartbeats
- Difficulty in swallowing
- Sudden weakness/numbness on one side of the body
- Vision problems and imbalance
- Seizures
- Hallucinations
Asenapine dosage
This drug was first approved for use in the US in 2009. Asenapine is available as sublingual tablets. The following doses of asenapine are available:
- 2.5 mg
- 5 mg
- 10 mg
The maintenance dose can be anywhere between 2.5 to 10 mg and is given two times a day.
Reviews of Asenapine
On WebMD website, asenapine has an average rating of 3.67 out of 5 stars for effectiveness, with a total of 3 reviews.
Another review:
Amoxapine (Brands: Ascendin)
Amoxapine belongs to a category of drugs known as tricyclic antidepressants (TCAs). It restores the balance of certain chemicals in the brain and is used to treat symptoms of
- depression
- anxiety
- agitation
Amoxapine has some effects similar to anti-anxiety drugs. Therefore, it works best in patients who have depression along with anxiety.
Side effects of Amoxapine
Treating depression can come with a price, but here’s the deal. First, you read the side effects and then we’ll give you tips to prevent them.
Amoxapine has the following side effects:
- Constipation
- Blurring of vision
- Weight changes
- Changes in appetite
- Headache
- Weakness
- Four D’s (dizziness, drowsiness, dry mouth, and difficulty in passing urine)
If any of these symptoms stay for long, inform your doctor or pharmacist. Some possible home remedies include sucking on a sugarless candy or gum to relieve dry mouth. But Do not opt for sugar products. They can cause swelling of oral tissues, especially the tongue if taken in large quantities. You can also use a saliva substitute.
To keep constipation at bay, include more fiber in your diet and drink plenty of water. Do exercise. If the problem persists, you may consider using laxatives.
Get immediate medical help if any of the following serious side effects occur (Note: These effects are unlikely):
- Hallucinations
- Fainting
- Severe vomiting
- Abdominal pain
- Swelling of arms and legs
- Seizures
- Chest pain
- Weakness on one side of the body
- Slurred speech
- Changes in heartbeat
- Ringing in ears
Amoxapine dosage
This drug was first approved for use in the US in 1992. Amoxapine is available under the brand name Ascendin. Manufacturers produce the following doses:
- 25 mg
- 50 mg
- 100 mg
- 150 mg
The recommended number of tablets per day depends on the potency of tablets you buy. Usually, the doctor will advise 50 mg dose twice or thrice daily. Later on, the dose may be increased based upon how well the drug performs and the tolerance of the patient. The dosage can go as high as 300 mg per day.
Reviews of Amoxapine
There were no negative reviews about amoxapine on WebMD website. All users seemed to be satisfied with this drug. Here’s a positive review:
Another positive review by a patient (age: 65-74) who has been on the treatment for 10 or more years.
Should you take dopaminergic drugs?
Almost all drugs have certain interactions with other medications, and some drugs are not suitable if a patient has certain medical history, such as liver or kidney disease.
It is not your job to decide whether a specific medicine is suitable for you or not. Always buy dopaminergic drugs on doctor’s prescription. Your doctor will prescribe dopamine medications only if the benefit is far greater than the risk n your case. If prescribed, you should take them.
Where to buy dopaminergic drugs?
You can buy dopaminergic agonists and antagonists from a local pharmacy or an online drug store. However, practice caution when buying drugs online. The U.S. Food and Drug Administration has warned against rogue online pharmacies.
Valid and authentic online pharmacies will have the following features:
- They do NOT sell drugs without a prescription from a licensed healthcare provider.
- They have a U.S. licensed pharmacist to answer your queries.
- They provide the street address and are located in the U.S.
- They carry a Verified Internet Pharmacy Practice SitesTM Seal (VIPPS® seal). Click here to find verified and safe online pharmacies.
Bottom Line
Now that you know of seven commonly used dopaminergic drugs, help your friends and family in pointing out any serious side effects. Dopaminergic drugs are safe for use in intended cases, but some individuals might report severe unwanted effects that require prompt medical action. Please consult your doctor if you notice any bad outcomes of these drugs.
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