A Brief Review of Basic Psych Pharmacology

Pharmacodynamics refers to what the drug does to the body at 4 specific target sites; receptors, ion channels, enzymes, and transport pumps. Think of pharmacodynamics as chemical reactions within our fragile bodies so the ideal with medications is not to explode with creativity but to be mindful and cautious with treatment.

Receptors

Psychiatric medications produce a wide variety of effects on neurotransmitter (NT) receptors. EACH neurotransmitter has several types of receptors and for each one, there may be multiple subtypes with different actions.

Therefore, one drug can have multiple different actions in the brain, depending on the distribution of that neurotransmitter pathway and receptors.  Newer drugs are more selective to hopefully minimize the side-effects but nevertheless, every drug causes a response. Types of receptors:

• Agonist: naturally occurring NT’s stimulate receptors, thus called agonists. Drugs that mimic the same action of that NT is also called agonists. Your body does not know the difference between the drug and your body’s NT, it just knows when its too much or not enough of it and tries to balance and regulate the NT.
• Antagonists: what blocks the actions of the agonists (only in the presence of the agonists). In the absence of the agonist, the antagonist has no effects i.e. naloxone (Narcan) is an opioid agonist and only works if an opioid is in the body. If there’s no heroin, Narcan will not work or wake the patient up.
• Inverse agonists: drugs that have the opposite actions of their agonists.
• Partial agonists: drugs that stimulate receptors only partially or less than the natural NT.

In General, the MOST concerning side-effects and causes

• Anticholinergic: acetylcholine (muscarinic) receptor blockage (antagonism)
• Extrapyramidal Side-Effects (EPS): dopamine receptor blockage (antagonism)
• Orthostatic Hypotension: adrenergic receptor blockage (antagonism)
• Sedation: histamine receptor blockage (antagonism)
• Sexual AE’s, anxiety, akathisia, insomnia, GI upset, and diarrhea: serotonergic receptor excessive activation (agonism)

Ion Channels

Ion channels exist for many ions, including the major electrolytes; calcium, chloride, potassium, and sodium. For example, calcium-channel blockers act by blocking the movement of calcium through channels. However, NT’s interacts with the receptor, causing it to change its configuration called “gating”. The effects of this action depend upon whether the NT is excitatory or inhibitory at the receptor sites. For example, glutamate is excitatory and one of its receptors (N-nitrosodimethylamine or NMDA) gates a calcium channel. Thus, when glutamate interacts with the NMDA receptor, calcium is allowed in, depolarizing the postsynaptic cell.

Enzymes

Enzymes are proteins that are important for metabolizing drugs i.e. monoamine oxidase (MAO) is an enzyme that metabolizes the monoamine NT’s serotonin, dopamine, and norepinephrine. MAO is located inside the terminals of catecholamine neurons. After the NT is released into the synaptic cleft and completes its action, it is pumped back into the terminal can destroy it (MAO inhibitors), by decreasing the NT being metabolized. More information about enzymes and P450

Transport Pumps

Proteins that actively carry NT molecules out of the synapse and back into the presynaptic neuron are another important form of medication. For example, selective reuptake inhibitors (SSRIs) block the reuptake to make serotonin levels increase with depressive disorders.

Major Classes of Medications Commonly used in Mental Health

• Anticholinergics: side-effects that develop with most psychotropics
• Antipsychotics, Neuroleptics, Tranquilizers: for psychosis, bipolar disorder, aggression, tic disorders
• Anticonvulsants, Mood Stabilizers: for bipolar disorder, aggression, mood disorders
• Anxiolytics, sedative-hypnotics: for anxiety, sleep disorders or insomnia, substance withdrawal
• Psychostimulants, Stimulants: for attention-deficit hyperactivity disorder, narcolepsy
• Cognitive enhancers: for dementia.

–Kim Hutchins, 2015

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An Overview of Psych Medications

Medications can play a role in treating several mental disorders and conditions. Treatment may also include psychotherapy (also called “talk therapy”) and brain stimulation therapies (less common). In some cases, psychotherapy alone may be the best treatment option. Choosing the right treatment plan should be based on a person’s individual needs and medical situation and under a mental health professional’s care.

The National Institute of Mental Health (NIMH), a federal research agency, does not provide medical advice or referrals. Resources that may help you find treatment services in your area are listed on our Help for Mental Illnesses web page.

NIMH also does not endorse or recommend any particular drug, herb, or supplement. Results from NIMH-supported clinical research trials (What are Clinical Research Trials?) that examine the effectiveness of treatments, including medications, are reported in the medical literature. This health topic webpage is intended to provide basic information about mental health medications. It is not a complete source for all medications available and should not be used as a guide for making medical decisions.

Information about medications changes frequently. Check the U.S. Food and Drug Administration (FDA) website for the latest warnings, patient medication guides, or newly approved medications. Brand names are not referenced on this page, but you can search by brand name on MedlinePlus Drugs, Herbs, and Supplements Drugs website. The MedlinePlus website also provides additional information about each medication, including side effects and FDA warnings.

Antidepressants

What are antidepressants? Antidepressants are medications commonly used to treat depression. Antidepressants are also used for other health conditions, such as anxiety, pain, and insomnia. Although antidepressants are not FDA-approved specifically to treat ADHD, antidepressants are sometimes used to treat ADHD in adults.

The most popular types of antidepressants are called selective serotonin reuptake inhibitors (SSRIs). Examples of SSRIs include:

• Fluoxetine
• Citalopram
• Sertraline
• Paroxetine
• Escitalopram

Other types of antidepressants are serotonin and norepinephrine reuptake inhibitors (SNRIs). SNRIs are similar to SSRIs and include venlafaxine and duloxetine.

Another antidepressant that is commonly used is bupropion. Bupropion is a third type of antidepressant that works differently than either SSRIs or SNRIs.  Bupropion is also used to treat seasonal affective disorder and to help people stop smoking.

SSRIs, SNRIs, and bupropion are popular because they do not cause as many side effects as older classes of antidepressants and seem to help a broader group of depressive and anxiety disorders.

Older antidepressant medications include tricyclics, tetracyclics, and monoamine oxidase inhibitors (MAOIs). For some people, tricyclics, tetracyclics, or MAOIs may be the best medications.

How do people respond to antidepressants?

According to a research review by the Agency for Healthcare Research and Quality, all antidepressant medications work about as well as each other to improve symptoms of depression and to keep depression symptoms from coming back. For reasons not yet well understood, some people respond better to some antidepressant medications than to others.

Therefore, it is important to know that some people may not feel better with the first medicine they try and may need to try several medicines to find the one that works for them. Others may find that a medicine helped for a while, but their symptoms came back. It is important to carefully follow your doctor’s directions for taking your medicine at an adequate dose and over an extended period of time (often 4 to 6 weeks) for it to work.

Once a person begins taking antidepressants, it is important to not stop taking them without the help of a doctor. Sometimes people take antidepressants to feel better and stop taking the medication too soon, and the depression may return. When it is time to stop the medication, the doctor will help the person slowly and safely decrease the dose. It’s important to give the body time to adjust to the change. People don’t get addicted (or “hooked”) to these medications, but stopping them abruptly may also cause withdrawal symptoms

What are the possible side effects of antidepressants?

Some antidepressants may cause more side effects than others. You may need to try several different antidepressant medications before finding the one that improves your symptoms and that causes side effects that you can manage.

The most common side effects listed by the FDA include:

• Nausea and vomiting
• Weight gain
• Diarrhea
• Sleepiness
• Sexual problems

Call your doctor right away if you have any of the following symptoms, especially if they are new, worsening, or worry you(U.S. Food and Drug Administration, 2011):

• Thoughts about suicide or dying
• Attempts to commit suicide
• New or worsening depression
• New or worsening anxiety
• Feeling very agitated or restless
• Panic attacks
• Trouble sleeping (insomnia)
• New or worsening irritability
• Acting aggressively, being angry, or violent
• Acting on dangerous impulses
• An extreme increase in activity and talking (mania)
• Other unusual changes in behavior or mood

Combining the newer SSRI or SNRI antidepressants with one of the commonly-used “triptan” medications used to treat migraine headaches could cause a life-threatening illness called “serotonin syndrome.”

A person with serotonin syndrome may be agitated, have hallucinations (see or hear things that are not real), have a high temperature, or have unusual blood pressure changes. Serotonin syndrome is usually associated with the older antidepressants called MAOIs, but it can happen with the newer antidepressants as well if they are mixed with the wrong medications.

Antidepressants may cause other side effects that were not included in this list. To report any serious adverse effects associated with the use of antidepressant medicines, please contact the FDA MedWatch program using the contact information at the bottom of this page. For more information about the risks and side effects of each medication, please see Drugs@FDA.

Anti-Anxiety Medications

What are anti-anxiety medications? Anti-anxiety medications help reduce the symptoms of anxiety, such as panic attacks, or extreme fear and worry. The most common anti-anxiety medications are called benzodiazepines. Benzodiazepines can treat generalized anxiety disorder. In the case of panic disorder or social phobia (social anxiety disorder), benzodiazepines are usually second-line treatments, behind SSRIs or other antidepressants.

Benzodiazepines used to treat anxiety disorders include:

• Clonazepam
• Alprazolam
• Lorazepam

Short half-life (or short-acting) benzodiazepines (such as Lorazepam) and beta-blockers are used to treat the short-term symptoms of anxiety. Beta-blockers help manage physical symptoms of anxiety, such as trembling, rapid heartbeat, and sweating that people with phobias (an overwhelming and unreasonable fear of an object or situation, such as public speaking) experience in difficult situations.

Taking these medications for a short period of time can help the person keep physical symptoms under control and can be used “as needed” to reduce acute anxiety.

Buspirone (which is unrelated to benzodiazepines) is sometimes used for the long-term treatment of chronic anxiety. In contrast to benzodiazepines, buspirone must be taken every day for a few weeks to reach its full effect. It is not useful on an “as-needed” basis.

How do people respond to anti-anxiety medications?

Anti-anxiety medications such as benzodiazepines are effective in relieving anxiety and take effect more quickly than the antidepressant medications (or buspirone) often prescribed for anxiety. However, people can build up a tolerance to benzodiazepines if they are taken over a long period of time and may need higher and higher doses to get the same effect. Some people may even become dependent on them. To avoid these problems, doctors usually prescribe benzodiazepines for short periods, a practice that is especially helpful for older adults (read the NIMH article: Despite Risks, Benzodiazepine Use Highest in Older People), people who have substance abuse problems, and people who become dependent on medication easily. If people suddenly stop taking benzodiazepines, they may have withdrawal symptoms or their anxiety may return. Therefore, benzodiazepines should be tapered off slowly.

What are the possible side effects of anti-anxiety medications?

Like other medications, anti-anxiety medications may cause side effects. Some of these side effects and risks are serious. The most common side effects of benzodiazepines are drowsiness and dizziness. Other possible side effects include:

• Nausea
• Blurred vision
• Headache
• Confusion
• Tiredness
• Nightmares

Tell your doctor if any of these symptoms are severe or do not go away:

• Drowsiness
• Dizziness
• Unsteadiness
• Problems with coordination
• Difficulty thinking or remembering
• Increased saliva
• Muscle or joint pain
• Frequent urination
• Blurred vision
• Changes in sex drive or ability (The American Society of Health-System Pharmacists, Inc, 2010)

If you experience any of the symptoms below, call your doctor immediately:

• Rash
• Hives
• Swelling of the eyes, face, lips, tongue, or throat
• Difficulty breathing or swallowing
• Hoarseness
• Seizures
• Yellowing of the skin or eyes
• Depression
• Difficulty speaking
• Yellowing of the skin or eyes
• Thoughts of suicide or harming yourself
• Difficulty breathing

Common side effects of beta-blockers include:

• Fatigue
• Cold hands
• Dizziness or light-headedness
• Weakness

Beta-blockers generally are not recommended for people with asthma or diabetes because they may worsen symptoms related to both.

Possible side effects from buspirone include:

• Dizziness
• Headaches
• Nausea
• Nervousness
• Lightheadedness
• Excitement
• Trouble sleeping

Anti-anxiety medications may cause other side effects that are not included in the lists above. To report any serious adverse effects associated with the use of these medicines, please contact the FDA MedWatch program using the contact information at the bottom of this page. For more information about the risks and side effects of each medication, please see Drugs@FDA.

Stimulants

What are Stimulants? As the name suggests, stimulants increase alertness, attention, and energy, as well as elevate blood pressure, heart rate, and respiration (National Institute on Drug Abuse, 2014). Stimulant medications are often prescribed to treat children, adolescents, or adults diagnosed with ADHD.

Stimulants used to treat ADHD include:

• Methylphenidate
• Amphetamine
• Dextroamphetamine
• Lisdexamfetamine Dimesylate

Note: In 2002, the FDA approved the non-stimulant medication atomoxetine for use as a treatment for ADHD. Two other non-stimulant antihypertensive medications, clonidine, and guanfacine are also approved for the treatment of ADHD in children and adolescents. One of these non-stimulant medications is often tried first in a young person with ADHD, and if the response is insufficient, then a stimulant is prescribed.

Stimulants are also prescribed to treat other health conditions, including narcolepsy, and occasionally depression (especially in older or chronically medically ill people and in those who have not responded to other treatments).

How do people respond to stimulants?

Prescription stimulants have a calming and “focusing” effect on individuals with ADHD. Stimulant medications are safe when given under a doctor’s supervision. Some children taking them may feel slightly different or “funny.”

Some parents worry that stimulant medications may lead to drug abuse or dependence, but there is little evidence of this when they are used properly as prescribed. Additionally, research shows that teens with ADHD who took stimulant medications were less likely to abuse drugs than those who did not take stimulant medications.

What are the possible side effects of stimulants?

Stimulants may cause side effects. Most side effects are minor and disappear when dosage levels are lowered. The most common side effects include:

• Difficulty falling asleep or staying asleep
• Loss of appetite
• Stomach pain
• Headache

Less common side effects include:

• Motor tics or verbal tics (sudden, repetitive movements or sounds)
• Personality changes, such as appearing “flat” or without emotion

Call your doctor right away if you have any of these symptoms, especially if they are new, become worse, or worry you.

Stimulants may cause other side effects that are not included in the list above. To report any serious adverse effects associated with the use of stimulants, please contact the FDA MedWatch program using the contact information at the bottom of this page. For more information about the risks and side effects of each medication, please see Drugs@FDA.

Antipsychotics

What are antipsychotics? Antipsychotic medicines are primarily used to manage psychosis. The word “psychosis” is used to describe conditions that affect the mind, and in which there has been some loss of contact with reality, often including delusions (false, fixed beliefs) or hallucinations (hearing or seeing things that are not really there). It can be a symptom of a physical condition such as drug abuse or a mental disorder such as schizophrenia, bipolar disorder, or very severe depression (also known as “psychotic depression”).

Antipsychotic medications are often used in combination with other medications to treat delirium, dementia, and mental health conditions, including:

• Attention-Deficit Hyperactivity Disorder (ADHD)
• Severe Depression
• Eating Disorders
• Post-traumatic Stress Disorder (PTSD)
• Obsessive-Compulsive Disorder (OCD)
• Generalized Anxiety Disorder

Antipsychotic medicines do not cure these conditions. They are used to help relieve symptoms and improve quality of life.

Older or first-generation antipsychotic medications are also called conventional “typical” antipsychotics or “neuroleptics”. Some of the common typical antipsychotics include:

• Chlorpromazine
• Haloperidol
• Perphenazine
• Fluphenazine

Newer or second-generation medications are also called “atypical” antipsychotics. Some of the common atypical antipsychotics include:

• Risperidone
• Olanzapine
• Quetiapine
• Ziprasidone
• Aripiprazole
• Paliperidone
• Lurasidone

According to a 2013 research review by the Agency for Healthcare Research and Quality, typical and atypical antipsychotics both work to treat symptoms of schizophrenia and the manic phase of bipolar disorder.

Several atypical antipsychotics have a “broader spectrum” of action than the older medications and are used for treating bipolar depression or depression that has not responded to antidepressant medications alone.

To find additional antipsychotics and other medications used to manage psychoses and current warnings and advisories, please visit the FDA website.

How do people respond to antipsychotics?

Certain symptoms, such as feeling agitated and having hallucinations, usually go away within days of starting an antipsychotic medication. Symptoms like delusions usually go away within a few weeks, but the full effects of the medication may not be seen for up to six weeks. Every patient responds differently, so it may take several trials of different antipsychotic medications to find the one that works best.

Some people may have a relapse—meaning their symptoms come back or get worse. Usually, relapses happen when people stop taking their medication, or when they only take it sometimes. Some people stop taking the medication because they feel better or they may feel that they don’t need it anymore, but no one should stop taking an antipsychotic medication without talking to his or her doctor. When a doctor says it is okay to stop taking a medication, it should be gradually tapered off— never stopped suddenly. Many people must stay on an antipsychotic continuously for months or years in order to stay well; treatment should be personalized for each individual.

What are the possible side effects of antipsychotics?

Antipsychotics have many side effects (or adverse events) and risks. The FDA lists the following side effects of antipsychotic medicines:

• Drowsiness
• Dizziness
• Restlessness
• Weight gain (the risk is higher with some atypical antipsychotic medicines)
• Dry mouth
• Constipation
• Nausea
• Vomiting
• Blurred vision
• Low blood pressure
• Uncontrollable movements, such as tics and tremors (the risk is higher with typical antipsychotic medicines)
• Seizures
• A low number of white blood cells, which fight infections

A person taking an atypical antipsychotic medication should have his or her weight, glucose levels, and lipid levels monitored regularly by a doctor.

Typical antipsychotic medications can also cause additional side effects related to physical movements, such as:

• Rigidity
• Persistent muscle spasms
• Tremors
• Restlessness

Long-term use of typical antipsychotic medications may lead to a condition called tardive dyskinesia (TD). TD causes muscle movements, commonly around the mouth, that a person can’t control. TD can range from mild to severe, and in some people, the problem cannot be cured. Sometimes people with TD recover partially or fully after they stop taking typical antipsychotic medication. People who think that they might have TD should check with their doctor before stopping their medication. TD rarely occurs while taking atypical antipsychotics.

Antipsychotics may cause other side effects that are not included in this list above. To report any serious adverse effects associated with the use of these medicines, please contact the FDA MedWatch program. For more information about the risks and side effects of antipsychotic medications, please visit Drugs@FDA.

Mood Stabilizers

What are mood stabilizers? Mood stabilizers are used primarily to treat bipolar disorder, mood swings associated with other mental disorders, and in some cases, to augment the effect of other medications used to treat depression. Lithium, which is an effective mood stabilizer, is approved for the treatment of mania and the maintenance treatment of a bipolar disorder. A number of cohort studies describe the anti-suicide benefits of lithium for individuals on long-term maintenance. Mood stabilizers work by decreasing abnormal activity in the brain and are also sometimes used to treat:

• Depression (usually along with an antidepressant)
• Schizoaffective Disorder
• Disorders of impulse control
• Certain mental illnesses in children

Anticonvulsant medications are also used as mood stabilizers. They were originally developed to treat seizures, but they were found to help control unstable moods as well. One anticonvulsant commonly used as a mood stabilizer is valproic acid (also called divalproex sodium). For some people, especially those with “mixed” symptoms of mania and depression or those with rapid-cycling bipolar disorder, valproic acid may work better than lithium. Other anticonvulsants used as mood stabilizers include:

• Carbamazepine
• Lamotrigine
• Oxcarbazepine

What are the possible side effects of mood stabilizers?

Mood stabilizers can cause several side effects, and some of them may become serious, especially at excessively high blood levels. These side effects include:

• Itching, rash
• Excessive thirst
• Frequent urination
• Tremor (shakiness) of the hands
• Nausea and vomiting
• Slurred speech
• Fast, slow, irregular, or pounding heartbeat
• Blackouts
• Changes in vision
• Seizures
• Hallucinations (seeing things or hearing voices that do not exist)
• Loss of coordination
• Swelling of the eyes, face, lips, tongue, throat, hands, feet, ankles, or lower legs.

If a person with bipolar disorder is being treated with lithium, he or she should visit the doctor regularly to check the lithium levels in his or her blood and make sure the kidneys and the thyroid are working normally.

Lithium is eliminated from the body through the kidney, so the dose may need to be lowered in older people with reduced kidney function. Also, loss of water from the body, such as through sweating or diarrhea, can cause the lithium level to rise, requiring a temporary lowering of the daily dose.

Although kidney functions are checked periodically during lithium treatment, actual damage of the kidney is uncommon in people whose blood levels of lithium have stayed within the therapeutic range.

Mood stabilizers may cause other side effects that are not included in this list. To report any serious adverse effects associated with the use of these medicines, please contact the FDA MedWatch program using the contact information at the bottom of this page. For more information about the risks and side effects of each individual medication, please see Drugs@FDA.

For more information on the side effects of Carbamazepine, Lamotrigine, and Oxcarbazepine, please visit MedlinePlus Drugs, Herbs, and Supplements.

Some possible side effects linked to anticonvulsants (such as valproic acid) include:

• Drowsiness
• Dizziness
• Headache
• Diarrhea
• Constipation
• Changes in appetite
• Weight changes
• Back pain
• Agitation
• Mood swings
• Abnormal thinking
• Uncontrollable shaking of a part of the body
• Loss of coordination
• Uncontrollable movements of the eyes
• Blurred or double vision
• Ringing in the ears
• Hair loss

These medications may also:

• Cause damage to the liver or pancreas, so people taking it should see their doctors regularly
• Increase testosterone (a male hormone) levels in teenage girls and lead to a condition called polycystic ovarian syndrome (a disease that can affect fertility and make the menstrual cycle become irregular)

Medications for common adult health problems, such as diabetes, high blood pressure, anxiety, and depression may interact badly with anticonvulsants. In this case, a doctor can offer other medication options.

–National Institute of Mental Health

For more information about the risks and side effects of each medication, please see Drugs@FDA.