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PSYCHIATRIC MEDICATIONS

Category: Medical

Topic: Psychiatric

Level: AEMT

Next Unit: Specific Psychiatric Disorders

24 minute read

Psychiatric Medications

 

Antipsychotics and antidepressants make up the lion's share of medications prescribed by psychiatrists. Others, such as amphetamines, phenothiazines, anti-anxiety sedatives, and antiseizure medications have been used with little success but have sometimes found a place as adjuvant therapy with a prime psychiatric medication.

Antidepressants

Introduction

We have come to learn that not treating depression, because of the risk of suicide, is much more dangerous than the side effects patients may fret over. The reality is that depression could get worse without treatment, leading to suicide. In the 1950s, the MAOs came out first, which inhibited an enzyme that broke down the neurotransmitter serotonin. Next came the tricyclic antidepressants (TCAs). Then came the selective reuptake inhibitors—the SSRIs (serotonin) and SNRIs (serotonin and norepinephrine).

DOPAMINE is the “reward” neurotransmitter. It’s what explains the high from recreational drugs, cigarettes, and other abused substances, but having large levels of it is the driving force behind addiction—which fuels cravings when levels drop.

Types of Antidepressants

TRICYCLIC ANTIDEPRESSANTS (TCAs): TCA's are the oldest antidepression drugs, they are less frequently used but are responsible for some of the most serious side effects and overdose effects which will be discussed later in the section. The generic names of TCA's tend to end in "Tryptiline" or "amine" For completeness sake, the TCA's are: amitriptyline (Elavil), nortriptyline (Triavil), clomipramine (Anafranil), dothiepin (Prothiaden), doxepin (Sinequan), and imipramine (Tofranil).

SELECTIVE SEROTONIN REUPTAKE INHIBITORS: (SSRIs): SSRI's are the most common antidepressants and are considered the "first line" drug for a variety of conditions, they have fewer dangerous side effects than TCA's and have a wider range of doses that are acceptable. The names of SSRI's tend to end in "-Pram or -Tine" The most common SSRI's are: citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac), fluvoxamine (Faverin, Fevarin, Floxyfral, Dumyrox, Luvox), paroxetine (Paxil), and sertraline (Zoloft).

SELECTIVE SEROTONIN AND NOREPINEPHRINE REUPTAKE INHIBITORS (SNRIs): SNRI's share most of the same indications and side effects as SSRI's and are generally used as a second agent if SSRI's fail in a patient, the most common SNRI's are: duloxetine (Cymbalta), venlafaxine (Effexor), and desvenlafaxine (Pristiq).

Side Effects of Antidepressants

Anticholinergic effects: TCA's have the most significant anticholinergic effects, SSRI's and SNRI's rarely cause anticholinergic effects. Watch for Drowsiness, insomnia, orthostatic hypotension, chronic weight changes, and changes in the cardiac electrical cycle. 

Cardiac effects as seen via EKG changes are the most feared side effect of TCA's and are usually only seen in overdose. These drugs can slow conduction velocity of the nerves and lea to a widening of the QRS interval: this can lead to dangerous hypotension, arrhythmia, and tachycardia/bradycardia. In these extreme cases, sodium bicarbonate is often administered. 

Discontinuation Effects: Abruptly stopping antidepressants can lead to a wide variety of uncomfortable and potentially dangerous symptoms: Dizziness, fatigue, headache, nausea, agitation, anxiety, chills, diaphoresis, insomnia, and myalgia/tremors are most common. 

Serotonin Syndrome: Serotonin syndrome (serotonin toxicity) is a potentially life-threatening condition associated with excess serotonin activity in the brain, this can occur if an overdose of SSRI/SNRI's are taken or if a drug that also affects serotonin is taken alongside these medications. Tachycardia and hypertension are the main signs of this syndrome. In severe cases, hyperthermia, dramatic blood pressure swings, tremor, extreme hyperreflexia, dilated pupils, and flushed/diaphoretic skin may be seen.

 

Antipsychotics

Mental illness filled a good portion of hospital beds before 1954, but when chlorpromazine (Thorazine) was introduced, the mental hospitals emptied. This breakthrough made it possible to mitigate symptoms to the point where people could be treated as outpatients and become functional in society. Since then, dozens of newer medications have been developed, reliably reducing the frightening hallucinations, delusions, paranoia and thought disorders common in psychosis.

Types of Antipsychotics:

FIRST GENERATIONS ANTIPSYCHOTICS (FGAs): The mechanism of action of the first-generation antipsychotics (FGAs) is blockade of brain dopamine receptors. These include:

  • high-potency FGAs (fluphenazine, haloperidol, loxapine, perphenazine, pimozide, thiothixene, and trifluoperazine): associated with little sedation, weight gain, or anticholinergic activity, but a high risk for extrapyramidal side effects.
  • low-potency FGAs (chlorpromazine and thioridazine) have an increased prevalence of sedation and anticholinergic effects, but lower risk of extrapyramidal side effects.

SECOND GENERATION ANTIPSYCHOTICS (SGAs):

These include the phenothiazines, which are also common in drugs for nausea, most of these work on both dopamine receptors and other receptors throughout the brain. The drug names tend to end in "-zine", the most common SGA's are: prochlorperazine (Compazine, Compro, Procomp), chlorpromazine (Promapar, Thorazine), fluphenazine (Permitil, Prolixin), perphenazine, trifluoperazine (Stelazine), and thioridazine (Mellaril).

Side Effects of Antipsychotics: 

Excessive use of phenothiazines can lead to drowsiness, dizziness, headache, hypotension, and blurred vision. However, the most feared side effect of all antipsychotics are extrapyramidal signs.

Extrapyramidal signs result from excess dopamine blockade and all affect motor activity: rigid muscles, reduced movement (bradykinesia), tremors, slurred speech, and dystonias (muscle spasms or contractions) are all extrapyramidal signs that are seen with excessive antipsychotic use. Tardive Dyskinesia is the most severe chronic side effect that is caused by these medications, it is far more common with first-generation antipsychotics. 

TARDIVE DYSKINESIA: a hyperkinetic movement disorder that lasts for over a month even when the antipsychotic med is stopped. In some cases it is permanent. The term tardive," or late, differentiates it from other extrapyramidal symptoms that usually appear very soon after exposure and that resolve after the drug is discontinued. Dyskinesia means involuntary movements and postures, including: chorea (jerky involuntary movements), athetosis (involuntary writhing movements), dystonia (muscular spasm and abnormal posture), akathisia (state of agitation, distress, and restlessness),

 

Amphetamines

Amphetamine medications are most often used for attention disorders such as ADHD they come in a variety of formulations and release rates, the most common are: Adderall, Adderall XR, Concerta, and Ritalin.

Side Effects of Amphetamines

Amphetamines are stimulants and can cause weight loss, anorexia, sleep disturbance, jitteriness, and emotional swings. Other side effects that occur rarely or with overdose are: Hypertension, Tachycardia, Priapism, and Psychotic symptoms.

 

Anti-Anxiety Agents

GENERALIZED ANXIETY DISORDER (GAD) is characterized by excessive worry and anxiety that are difficult to control, cause significant distress and impairment, and occur on more days than not for at least six months.

The following medications are prescribed for GAD: Benzodiazepines (diazepam, alprazolam, etc.), SSRIs (paroxetine, sertraline, citalopram, and escitalopram, SNRIs (venlafaxine, duloxetine), Buspirone, and Pregabalin anticonvulsant (Lyrica).

BENZODIAZEPINES potentiate the neurotransmitter GABA, the main inhibitory neurotransmitter.

Side effects of benzodiazepines include: impairment of psychomotor performance, amnesia, and dependence and withdrawal symptoms after long-term treatment.

Withdrawal and cognitive or learning impairment are more likely in abrupt cessation for persons taking higher doses or habituated to specific benzos with shorter half-lives (alprazolam, lorazepam, and oxazepam).

As such, in the field, you are more likely to confront a withdrawal situation associated with alprazolam (Xanax), lorazepam (Ativan), or oxazepam.

Withdrawal can result in seizures. It is the half-life (time it takes for the drug to be 50% metabolized) that governs when withdrawal symptoms appear. Benzodiazepines with longer elimination half-lives (clorazepate, diazepam, flurazepam, prazepam, and clonazepam) usually produce more delayed and somewhat milder withdrawal symptoms.

Tapering off benzodiazepines is usually done very slowly, at approximately a 10% dose reduction per 1-2 weeks. Early signs of withdrawal include anxiety, dysphoria, and tremor; advanced manifestations include perceptual disturbances, psychosis, and seizures.

 

In the Field

In the field, your most likely encounters with psychiatric patients will require attention to safety, due to agitation and combativeness of the patient. However, also important to consider are the unusual presentations of toxicities of, and withdrawal from, psychiatric medications, which can present as medical emergencies:

  • Seizures from abrupt withdrawal from short half-life diazepines.
  • Cardiac arrhythmias from tricyclic antidepressants.
  • Anticholinergic effects of antidepressants (hyperthermia, flushing, dilated pupils).
  • Serotonin syndrome from antidepressants (hyperthermia, dramatic swings in pulse and blood pressure, etc).
  • Delirium and agitation from antidepressants.
  • Hypertension, tachycardia, priapism, and psychotic symptoms from amphetamines.
  • Extrapyramidal signs from phenothiazines or tardive dyskinesia from antipsychotics.

These are all potentially life-threatening, so your role in these types of calls is to support and transport, maintenance of ABC (airway, breathing, circulation), and assurance of safety and possibly restraints. Collecting and bringing medication bottles is important for the receiving facility.