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Which drug type is primarily used to promote sleep?
What is a common side effect of anxiety symptoms?
Which of the following benzodiazepines is commonly used for anxiety relief?
What parameter is NOT typically tested to determine the specific type of benzodiazepine?
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Which characteristic of benzodiazepines is more suitable for hypnotics?
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Which type of receptor is associated with benzodiazepines in the brain?
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What is a potential therapeutic use of sedative-anxiolytic-hypnotic drugs beyond treating anxiety?
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Which benzodiazepine is likely to have a longer duration of action?
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What is a primary effect of overdose on barbiturates?
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Which of the following conditions is contraindicated for barbiturate use?
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What is a consequence of prolonged barbiturate usage?
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What psychological effect may occur with regular barbiturate use?
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How do barbiturates primarily affect the cardiovascular system?
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What is the risk related to the use of barbiturates during pregnancy?
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After how many hours does withdrawal syndrome from barbiturates typically begin?
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What is a common adverse effect associated with chronic barbiturate use?
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Which benzodiazepine is classified as short-acting?
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What is the half-life of alprazolam?
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What is a potential consequence of using benzodiazepines during pregnancy?
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What is the primary neurotransmitter that BZD receptors interact with to produce sedation?
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Which of the following is true regarding withdrawal symptoms from benzodiazepines?
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Which action of BZDs is primarily associated with high doses?
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Which benzodiazepine has the longest half-life among the following?
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How does tolerance develop with benzodiazepine use?
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What therapeutic use of BZDs is indicated for treating children?
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Which of the following properties is NOT associated with BZDs?
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When does dependence typically appear with the use of short half-life benzodiazepines?
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What is the role of active metabolites in long-acting benzodiazepines?
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What is the safety profile of BZDs in terms of lethal and therapeutic doses?
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Which area of the brain do BZDs selectively inhibit to reduce anxiety?
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Which BZD function is primarily related to increasing presynaptic inhibition in the spinal cord?
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For which procedure are shorter-acting BZDs often used as premedication?
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What is the primary active intermediate produced from chloralhydrate in the body?
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What is a potential effect of combining chloral with ethanol after prolonged use?
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Which drug is used primarily for short-term sedation and is an antihistamine?
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Which of the following acts on the BZ1 receptor and is not a benzodiazepine?
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What is a likely consequence of rifampin co-administration with zolpidem?
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What forms when trichloroethanol is conjugated with glucuronic acid?
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Which medication undergoes hepatic oxidation by the CYP450 system?
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What is the expected duration of sleep induced by chloralhydrate?
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Study Notes
Anxiolytic, Sedative and Hypnotic Drugs
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Overview:
- Anxiolytics treat anxiety symptoms.
- Sedatives calm patients without inducing sleep.
- Hypnotics promote sleep.
- These drugs can be used for anticonvulsant, antiepileptic, and muscle relaxant purposes.
- Anxiety Symptoms: Include tachycardia, sweating, palpitations, tremor, trembling, gastrointestinal disorders, and sleep disturbances.
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Benzodiazepines (BZDs):
- Over 2000 benzodiazepines have been synthesized, with over 100 used clinically.
- Common BZDs include alprazolam, chlorodiazepoxide, clonazepam, diazepam, estazolam, flurazepam, lorazepam, midazolam, oxazepam, temazepam, and triazolam.
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Types are determined by:
- Drug's half-life (t½).
- Presence and half-life of active metabolites.
- Speed of absorption, solubility, and passage into the CNS.
- Long t½ BZDs/metabolites are suitable for anxiety treatment, while short t½ BZDs/metabolites are better for promoting sleep.
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BZD Mechanism of Action:
- BZDs interact with specific BZD1, BZD2, and BZD3 receptors in the brain.
- These receptors are located near GABA receptors and chloride ion channels, forming a complex.
- BZDs enhance GABA's inhibitory effect, leading to chloride channel opening, resulting in sedation.
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Pharmacological Actions of BZDs:
- Anxiolytic: BZDs reduce anxiety by inhibiting neuronal circuits in the limbic system at low doses.
- Sedative and Hypnotic: All BZDs possess sedative properties, with some inducing hypnosis at higher doses.
- Anticonvulsant: Some BZDs exhibit anticonvulsant activity, used to treat epilepsy.
- Muscle Relaxant: BZDs relax skeletal muscle spasticity by increasing presynaptic inhibition in the spinal cord.
- Amnesia: Short-acting BZDs are used as premedication for anxiety-provoking procedures to induce amnesia (e.g., endoscopy, bronchoscopy, dental).
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Therapeutic Uses of BZDs:
- Anxiety (with or without psychotic states).
- Panic attacks.
- Insomnia.
- Alcohol withdrawal.
- Sleepwalking (somnambulism) in children.
- Muscle spasms from various causes (e.g., epilepsy).
- Anesthesia and sedation for endoscopies.
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BZD Safety and Pharmacology:
- BZDs are relatively safe, with the lethal dose being over 1000 times higher than the therapeutic dose.
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Sleep Disorders: Not all BZDs are effective hypnotics, but those commonly prescribed include:
- Flurazepam (long-acting).
- Temazepam (intermediate-acting).
- Triazolam (short-acting).
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Pharmacokinetics:
- Absorption and distribution: BZDs are rapidly and fully absorbed orally, distributing throughout the body.
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Duration of action: The half-life of BZDs determines their therapeutic usefulness.
- Long-acting BZDs form active metabolites with long half-lives, leading to prolonged effects.
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Tolerance and Dependence: Tolerance can develop with chronic use, with cross-tolerance among BZDs.
- Dependence develops earlier with short t1/2 BZDs (e.g., alprazolam, lorazepam) compared to long t1/2 BZDs (e.g., diazepam).
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Barbiturates:
- Potent antidotes for convulsant drugs: Barbiturates can abolish convulsions arising from conditions like tetanus, eclampsia, and local anesthetic overdoses (e.g., procaine, cocaine).
- Respiratory Depression: High doses of ultra-short-acting barbiturates induce death due to respiratory failure, caused by the depression of the respiratory center.
- Cardiovascular effects: Hypnotic and anesthetic doses of barbiturates lower blood pressure by reducing cardiac output. Toxic doses can lead to heart failure.
- Tolerance: Tolerance can develop within 14 days of continuous use, possibly due to enzyme induction.
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Psychological and Physical Dependence: Regular doses of 0.4 g/day or more can lead to dependence.
- Withdrawal symptoms start 8-38 hours after cessation and last 8-14 days.
- Symptoms include anxiety, twitching, intention tremor, weakness, dizziness, visual distortion, nausea, delirium, convulsions, and coma.
- Withdrawal symptoms start 8-38 hours after cessation and last 8-14 days.
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Pharmacokinetics:
- Barbiturates are absorbed orally and distributed throughout the body, from the brain to skeletal muscle and adipose tissues.
- They readily cross the placenta and can depress the fetus.
- Excretion is primarily hepatic, with little urinary excretion except for phenobarbital.
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Contraindication:
- Pulmonary insufficiency.
- Hepatic failure.
- Porphyria.
- Elderly patients due to potential paradoxical effects (e.g., excitation, paranoia, suicidal tendency).
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Acute Adverse Effects:
- Coma.
- Respiratory and circulatory failure, leading to renal failure.
- Allergic reactions (especially with phenobarbital).
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Trichloroethanol Derivatives:
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Chloral hydrate: Converted in the body to active trichloroethanol by alcohol dehydrogenase, with hypnotic effects.
- Gastric irritation can occur when diluted in water, but flavored solutions reduce irritation.
- Induces sleep within 30 minutes, lasting 6-8 hours.
- Trichloroethanol is inactivated by conjugation with glucuronic acid.
- Other chloral derivatives: Triclofose and chloralbetaine are alternatives.
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Drug Interactions:
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Ethanol: Trichloroethanol competitively inhibits the conversion of ethanol to acetaldehyde, increasing ethanol plasma concentration.
- Chronic chloral use followed by alcohol ingestion can cause vasodilation, hypotension, and tachycardia.
- Warfarin: Enhances anticoagulant effect.
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Ethanol: Trichloroethanol competitively inhibits the conversion of ethanol to acetaldehyde, increasing ethanol plasma concentration.
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Chloral hydrate: Converted in the body to active trichloroethanol by alcohol dehydrogenase, with hypnotic effects.
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Other Hypnotic Drugs:
- Antidepressants: Can be effective long-term for managing chronic anxiety disorders, particularly in patients with substance addiction or dependence.
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Phenothiazines:
- Promethazine: A long-acting hypnotic, especially in children. Also an H1 receptor antagonist (antihistamine).
- Trimeprazine: Used for short-term sedation and hypnosis in children. Also an antihistamine.
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Zolpidem:
- New hypnotic drug, not a benzodiazepine structurally, but acts on BZD1 receptors.
- As effective as flunitrazepam.
- Rapid onset and short half-life, providing hypnotic effects for approximately 5 hours.
- Metabolized by CYP450 system to inactive products.
- Drugs that induce CYP450 (e.g., rifampin) shorten zolpidem's half-life.
- Similar drugs in action: Zaleplon and eszopiclone.
- Meprobamate and Chlormezanone: Centrally acting muscle relaxants with sedative-hypnotic effects.
- Bromides:
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Description
This quiz covers essential information about anxiolytic, sedative, and hypnotic drugs, including their uses, symptoms of anxiety, and details about benzodiazepines. It discusses the classification of these drugs based on their pharmacokinetics and clinical applications. Perfect for students in pharmacology or medicine.
