Review,Aug/20:Movement disorders caused by psych. meds that don't block dopamine

The full title of this American review is "Movement disorders induced by psychiatric drugs that do not block dopamine receptors".

https://pubmed.ncbi.nlm.nih.gov/32871538/

Abstract

Most movement disorders in psychiatric patients are induced by neuroleptic antipsychotic medications, all of which are dopamine D2 receptor blocking drugs. These include: acute onset disorders: dystonic reactions, akathisia and the neuroleptic malignant syndrome (NMS); non-acute onset parkinsonism; and the tardive syndromes. However, many other medications, when used at recommended doses, also induce movement disorders, with tremor being the most common. With the exception of serotonin syndrome, they are rarely as severe or disabling as the neuroleptic extrapyramidal syndromes may be. The serotonin reuptake inhibiting (SSRI) drugs are associated with the serotonin syndrome, a life-threatening disorder, but may also cause tremor and akathisia. While SSRI's have been thought to occasionally cause a tardive dyskinesia-like syndrome, this almost never occurs without prior or concurrent neuroleptic exposure as well. There also are few reliable data to support an association between antidepressants and parkinsonism. Valproic acid has been shown to cause parkinsonism, and lithium may as well, in addition to both having the well-known side effect of tremors. Myoclonus and asterixis are usually induced by toxic levels of medications but may appear with therapeutic levels, particularly with anticonvulsant mood stabilizers, and clozapine. Ataxia rarely occurs with non-toxic levels of drug, particularly anticonvulsants, benzodiazepines and lithium.

The full title of this American review is "Movement disorders induced by psychiatric drugs that do not block dopamine receptors".

 

https://pubmed.ncbi.nlm.nih.gov/32871538/

 

Abstract

 

Most movement disorders in psychiatric patients are induced by neuroleptic antipsychotic medications, all of which are dopamine D2 receptor blocking drugs. These include: acute onset disorders: dystonic reactions, akathisia and the neuroleptic malignant syndrome (NMS); non-acute onset parkinsonism; and the tardive syndromes. However, many other medications, when used at recommended doses, also induce movement disorders, with tremor being the most common. With the exception of serotonin syndrome, they are rarely as severe or disabling as the neuroleptic extrapyramidal syndromes may be. The serotonin reuptake inhibiting (SSRI) drugs are associated with the serotonin syndrome, a life-threatening disorder, but may also cause tremor and akathisia. While SSRI's have been thought to occasionally cause a tardive dyskinesia-like syndrome, this almost never occurs without prior or concurrent neuroleptic exposure as well. There also are few reliable data to support an association between antidepressants and parkinsonism. Valproic acid has been shown to cause parkinsonism, and lithium may as well, in addition to both having the well-known side effect of tremors. Myoclonus and asterixis are usually induced by toxic levels of medications but may appear with therapeutic levels, particularly with anticonvulsant mood stabilizers, and clozapine. Ataxia rarely occurs with non-toxic levels of drug, particularly anticonvulsants, benzodiazepines and lithium.

Benzodiazepines can cause serious balance issues and slow down reaction time. As a result, they can cause falls, fractures and motor vehicle accidents (lots of studies reflect this). As a person who is still dizzy and who has already had a slow-healing foot fracture as a result of this, I can say that it's extremely painful and debilitating. As well, there are numerous studies that show benzodiazepines in the blood of people who have died in motor vehicle accidents.

This StatPearls report on benzodiazepines does list ataxia, as well as numerous other adverse effects:

https://www.ncbi.nlm.nih.gov/books/NBK470159/

Here's an excerpt:

Adverse Effects

Common adverse effects of benzodiazepine administration include, but is not limited to:

    Respiratory depression

    Respiratory arrest

    Drowsiness

    Confusion

    Headache

    Syncope

    Nausea/vomiting

    Diarrhea

    Tremor

In neonates, less than 1% of patients treated with benzodiazepines experience laryngospasm and/or bronchospasm. They may also experience ventricular arrhythmias including ventricular bigeminy or premature ventricular contractions, vasovagal syncope, bradycardia, or tachycardia. Gastrointestinal reactions may include retching, nausea/vomiting, and excess salivation. CNS and neuromuscular adverse effects may include euphoria, hallucination, ataxia, dizziness, seizure-like activity, and paresthesia. Visual disturbances may include diplopia (“double vision”), cyclic eyelid movement, loss of balance, and difficulty focusing the eyes on objects.

Benzodiazepines may interact with ethanol, other benzodiazepines, and sedatives such as barbiturates, resulting in increased respiratory depression via a synergistic effect. Therefore, concomitant administration of benzodiazepines with patients under the influence of the preceding drugs should be carefully performed, with respiratory monitoring in place.

Contraindications

Contraindications include known hypersensitivity to benzodiazepines and narrow-angle glaucoma. Glaucoma occurs when the intraocular pressure rises, thereby causing compression of the optic nerve near the posterior surface of the eye. Upon compression, the flow of cytoplasm from the cell body of the optic nerve starves the nerve fibers leading to the brain. This results in numerous issues, including ocular pain, nausea/vomiting, blurred vision, an intraocular pressure greater than 21 mmHg, edema of the corneal epithelium, and non-reactive pupils.

As always, follow local protocols or contact Medical Control if any questions regarding administration, or withholding thereof, exist.

Monitoring

As noted above, these drugs may act as depressants to the CNS, specifically inhibiting respiratory drive. Therefore, careful monitoring of all vitals, especially blood pressure and respiratory rate, should be performed after administration of benzodiazepines. Waveform capnography, if available, should be seriously considered to monitor respiratory status.

Though the therapeutic index of benzodiazepines is high, monitoring of respiratory depression is critical. Respiratory arrest has been noted to occur with rapid injection of benzodiazepines via the intravenous route.

This Mayo Clinic webpage on ataxia also lists benzodiazepines as a possible cause:

https://www.mayoclinic.org/diseases-conditions/ataxia/symptoms-causes/syc-20355652 

Here's the excerpt:

Causes

Damage, degeneration or loss of nerve cells in the part of your brain that controls muscle coordination (cerebellum), results in ataxia. Your cerebellum comprises two portions of folded tissue situated at the base of your brain near your brainstem. This area of the brain helps with balance as well as eye movements, swallowing and speech.

Diseases that damage the spinal cord and peripheral nerves that connect your cerebellum to your muscles also can cause ataxia. Ataxia causes include:

Head trauma. Damage to your brain or spinal cord from a blow to your head, such as might occur in a car accident, can cause acute cerebellar ataxia, which comes on suddenly.

Stroke. Either a blockage or bleeding in the brain can cause ataxia. When the blood supply to a part of your brain is interrupted or severely reduced, depriving brain tissue of oxygen and nutrients, brain cells die.

Cerebral palsy. This is a general term for a group of disorders caused by damage to a child's brain during early development — before, during or shortly after birth — that affects the child's ability to coordinate body movements.

Autoimmune diseases. Multiple sclerosis, sarcoidosis, celiac disease and other autoimmune conditions can cause ataxia.

Infections. Ataxia can be an uncommon complication of chickenpox and other viral infections such as HIV and Lyme disease. It might appear in the healing stages of the infection and last for days or weeks. Normally, the ataxia resolves over time.

Paraneoplastic syndromes. These are rare, degenerative disorders triggered by your immune system's response to a cancerous tumor (neoplasm), most commonly from lung, ovarian, breast or lymphatic cancer. Ataxia can appear months or years before the cancer is diagnosed.

Abnormalities in the brain. An infected area (abscess) in the brain may cause ataxia. A growth on the brain, cancerous (malignant) or noncancerous (benign), can damage the cerebellum.

Toxic reaction. Ataxia is a potential side effect of certain medications, especially barbiturates, such as phenobarbital; sedatives, such as benzodiazepines; antiepileptic drugs, such as phenytoin; and some types of chemotherapy. Vitamin B-6 toxicity also may cause ataxia. These causes are important to identify because the effects are often reversible.

Also, some medications you take can cause problems as you age, so you might need to reduce your dose or discontinue the medication.

Alcohol and drug intoxication; heavy metal poisoning, such as from lead or mercury; and solvent poisoning, such as from paint thinner, also can cause ataxia.

Vitamin E, vitamin B-12 or thiamine deficiency. Not getting enough of these nutrients, because of the inability to absorb enough, alcohol misuse or other reasons, can lead to ataxia.

Thyroid problems. Hypothyroidism and hypoparathyroidism can cause ataxia.

COVID-19 infection. This infection may cause ataxia, most commonly in very severe cases.

For some adults who develop sporadic ataxia, no specific cause can be found. Sporadic ataxia can take a number of forms, including multiple system atrophy, a progressive, degenerative disorder.