Temazepam (anxiolytic): uses, characteristics and side effects

This benzodiazepine is used to relieve states of anxiety and insomnia in certain patients.

Benzodiazepines are a group of drugs that slow down the central nervous system and decrease neuronal excitation.

Although there are different types, these drugs are mainly used as anxiolytics, hypnotics and muscle relaxants. Temazepam is an example of a benzodiazepine used to help fall asleep and reduce nighttime awakenings.

In this article we explain what temazepam is, its main characteristics and uses.What are its main characteristics and clinical uses, its mechanism of action, and the side effects, interactions and contraindications that should be taken into account when using this drug.

Temazepam: characteristics and clinical uses

Temazepam is a drug of the benzodiazepine group used mainly in the treatment of insomnia and severe or disabling sleep disorders. and severe or disabling sleep disorders. This drug is also used in anxiety disorders, since in addition to having hypnotic effects, it exerts an anxiolytic and sedative action. Its half-life is approximately 10 hours, making it suitable for treating maintenance insomnia.

This compound was patented in 1962, and marketed for medical use in 1969 under the name "Restoril". In 1982 it was approved by the Food and Drug Administration (FDA), and it is now manufactured in generic form by several pharmaceutical companies.

In sleep laboratory studies, temazepam has been shown to significantly decrease the number of nighttime awakenings, although it has a distorting effect on normal sleep patterns. This drug is usually administered orally and the effects begin sixty minutes later, with a total duration of up to eight hours.

The prescription and use of benzodiazepines is widespread in the population, especially among the elderly.especially among the elderly. And although temazepam is a relatively safe and effective drug, its use quickly generates tolerance to its hypnotic and anxiolytic effects, resulting in the need to increase the dose. Prescribing guidelines usually limit the use of this type of medication to two to four weeks, due to tolerance and dependence problems.

Because benzodiazepines can be abused, their use should be avoided in people in certain high-risk groups, such as people with a history of alcohol or other drug dependence, people with emotional problems, and patients with severe mental disorders.

Mechanism of Action

Temazepam, like many other similar benzodiazepines, acts as a gamma-aminobutyric acid (GABA) modulator and is capable of eliciting a variety of effects including: sedation, hypnosis, skeletal muscle relaxation, anticonvulsant activity, and anxiolytic action.

GABA is considered the primary inhibitory neurotransmitter in the human body. When this neurotransmitter binds to GABAA receptors found in neuronal synapses, chloride ions are conducted across the cell membranes of neurons through an ion channel in the receptors. With sufficient chloride ions, the membrane potentials of the associated local neurons become hyperpolarized, making it more difficult or less likely that action potentials will fire, resulting in less excitation of the neurons..

Although the main pharmacological activity of temazepam is to increase the effect of the neurotransmitter GABA, animal studies (specifically, in rats) have also shown that the drug triggers the release of vasopressin in the paraventricular nucleus of the hypothalamus and decreases the release of adrenocorticotropic hormone under stress conditions.

Interactions and contraindications

As with other benzodiazepines, temazepam produces central nervous system depressant effects when co-administered with other drugs that also produce this depressant effect, such as barbiturates, alcohol, opioids, tricyclic antidepressants, non-selective MAO inhibitors, phenothiazines and other antipsychotics, muscle relaxants, antihistamines and anesthetics.

Administration of theophylline or aminophylline has been shown to reduce the sedative effects of temazepam and other benzodiazepines.. Unlike many other benzodiazepines, pharmacokinetic interactions involving cytochrome P450 have not been observed with temazepam.

In addition, temazepam shows no significant interaction with cytochrome CYP3A4 inhibitors, and oral contraceptives may decrease the effectiveness of this drug and accelerate its elimination half-life. On the other hand, the use of temazepam should be avoided, if possible, in people with these conditions:

• Ataxia (inability to coordinate muscle movements).

• Severe hypoventilation

• Severe liver impairment, such as hepatitis or cirrhosis.

• Severe renal impairment (e.g. dialysis patients).

• Closed-angle glaucoma

• Sleep apnea

• Severe depression, especially if accompanied by suicidal tendencies.

• Acute intoxication with alcohol and other psychoactive substances

• Myasthenia gravis

• Hypersensitivity or Allergy to benzodiazepines.

Side effects

The use of temazepam is not without possible side effects and adverse reactions.. The most common and shared by the vast majority of benzodiazepines are related to central nervous system depression and include: drowsiness, sedation, intoxication, dizziness, fatigue, ataxia, headache, lethargy, impaired memory and learning.

There may also be impaired motor function and coordination, slurred speech, decreased physical performance, emotional numbness, decreased alertness, muscle weakness, blurred vision and lack of concentration. Rarely, a state of euphoria has been reported following temazepam use. In addition, retrograde amnesia and respiratory depression have been reported at high doses.

In a 2009 meta-analysis a 44% increase in the rate of occurrence of mild infections, such as pharyngitis and sinusitis, was found.The results of this study have been reported in people who had taken temazepam or other hypnotic drugs compared to those who took a placebo.

On the other hand, cases of hyperhidrosis, hypotension, burning eyes, increased appetite, changes in libido, hallucinations, fainting, nystagmus, vomiting, pruritus, gastrointestinal disorders, nightmares, palpitations and paradoxical reactions such as restlessness, aggression, violence, overstimulation and agitation have been reported (in less than 0.5% of cases).

Bibliographic references:

• Mitler, M. M., Mary A. Carskadon, R. L. Phillips, W. R. Sterling, V. P. Zarcone, R. Spiegel Jr, C. Guilleminault, & W. C. Dement. "Hypnotic efficacy of temazepam: a long-term sleep laboratory evaluation." British journal of clinical pharmacology 8, no. Suppl 1 (1979): 63S.

• Ruben, S. M., & Morrison, C. L. (1992). Temazepam misuse in a group of injecting drug users. British Journal of Addiction, 87(10), 1387-1392.

• Schwarz, H. J. (1979). Pharmacokinetics and metabolism of temazepam in man and several animal species. British journal of clinical pharmacology, 8(Suppl 1), 23S.