Pharmacology set 1

are used to reduce anxiety and to help induce sleep.

a sudden onset of anxiety, sometimes accompanied by a sense of imminent danger, impending doom, or a sudden urge to escape.

anxiety over a specific stressful situation (e.g. a pharmacology quiz).

prolonged anxiety (multiple months), often over minor or vague possibilities, as well as specific events.

There are three families of sedatives: 1. GHB (gamma hydroxybutyric acid) 2. barbiturates 3. benzodiazepines

gamma hydroxybutyric acid)

gamma aminobutyric acid

All three families work by activating the chloride ion channel in neural membranes. They do so by activating GABA (gamma aminobutyric acid) modulated chloride receptors . When GABA binds to a GABA receptor it opens a Cl-1 specific ion channel in neural membranes (usually) allowing more chloride ion into the cell, which increases the negative potential on the inside of the membrane, and causing hyperpolarization in the post-synaptic membrane and inhibiting post-synaptic neuron firing.

GABA stimulation in the limbic system of the brain reduces anxiety; GABA stimulation in the cortical areas of the brain promotes sleep; GABA in the hippocampus and cerebral cortex induces amnesia. Often the same drug will relieve anxiety at low dosages and promote sleep at high dosages.

Large oral doses of GHB can result in sedation. Although it can be legally prescribed for a few rare diseases such as narcolepsy, its primary use is as an illegal date rape drug.

were commonly used from 1912 through ~1960 for anxiety and insomnia but their low therapeutic index due to respiratory depression has caused them to be largely replaced by the benzodiazepines. Current uses include the treatment of seizures, induction of anesthesia, and treatment of pain. Barbiturates work by directly stimulating the inhibitory GABA type chloride channels as well as inhibiting certain types of stimulatory (glutamate) receptors. Both actions cause a reduction in CNS activity.

is still used occasionally for treatment of seizures.

is used for induction of anesthesia.

(a combination of the barbiturate butalbital, aspirin and caffeine) and Fioricet (a combination of acetaminophen, butalbital and caffeine) are prescribed for tension headaches and migraines. It is also available as Fiorinal + codeine. It has been shown to be better than placebo for tension headaches; no definitive studies for migraines are available0. The butalbital can cause dependence and intoxication similar to alcohol consumption.

1. respiratory depression which can be lethal, especially when combined with alcohol (Marilyn Monroe died of an overdose of alcohol and barbiturates; Kurt Cobain nearly died of an overdose of barbiturates and alcohol 2 months before he shot himself; Jimi Hendrix choked to death on his own vomit while overdosed on barbiturates) 2. physical dependence

Benzodiazepines potentiate the effect of naturally occurring GABA but the effect is limited by the level of naturally occurring GABA, so there is less likelihood of severe respiratory depression than there is with the barbiturates. All benzodiazepines are lipophilic, and will therefore pass through the blood-brain barrier. They produce minimal respiratory depression and have a much better TI than barbiturates.

a small dose will reduce anxiety, larger doses will induce sleep.

of anxiety, insomnia; diazepam and lorazepam are also used for treating DT’s (delirium tremens) during alcohol withdrawal, status epilepticus (continuous seizures). Midazolam is used for producing amnesia during surgical procedures.

psychological dependence appears to be higher for drugs with shorter half lives (Halcion and Xanax especially have a tendency to cause an American Express Card syndrome.) 2. amnesia 3. sudden withdrawal from large doses may induce paranoia, delirium, or anxiety attacks. The book I’m Dancing as Fast as I Can, an autobiography by Barbara Gordon, provides a chilling account of an extreme case of Valium withdrawal)

(#9 most commonly prescribed drug in US) It is used to treat anxiety and panic attacks. It is very habit forming.

is one of the most commonly used benzodiazepine. It is used for anxiety, alleviating the withdrawal symptoms of alcoholics (delirium tremens or DT’s) which include tremors, vomiting, hallucinations and seizures. It is also a common drug for treating status epilepticus and the nausea associated with chemotherapy (in combination with other antinausea drugs).

is commonly used in the treatment of absence seizures, and has unlabelled use for schizophrenia, neuralgias, and depression.

is commonly used for insomnia.

is occasionally used to treat anxiety before surgical or dental procedures, muscle spasticity. It can also be used IV for status epilepticus.

was one of the first benzodiazepines on the market. It has rapid action but short duration, due to rapid absorption and metabolism. It is used for inducing sleep. Amnesia can be a problem. It is rarely prescribed anymore.

is given IV before surgery or unpleasant medical procedures (colonoscopy, radiographic procedures) to produce sedation and amnesia.

is ten times as strong as Valium. It has been used to treat insomnia outside of the U.S. (It is not legal in the U.S.). "Roofies" are notorious as a "date-rape" drug.

is a new hypnotic used in the treatment of insomnia. It is structurally unlike the benzodiazepines, but appears to bind the GABA receptors (perhaps at a different site from benzodiazepines). It causes little or no respiratory depression and little or no daytime drowsiness (1-2%).Generic form now available although a long acting form is under patent and being heavily promoted.

Lunesta is the new non-benzodiazepine on the market . It is thought to work by activating GABA receptors in the brain. It is under patent and being heavily advertised.

is an anti-anxiety agent acting on the hypothalamus. It reduces anxiety before medical procedures. It is also used for nausea and allergies.

is a new anti-anxiety agent that does not have sedative effects (so it is not used as a hypnotic). It appears particularly efficacious for anxiety associated with depression. Anti-anxiety effects take several weeks to develop, so it will not work to relieve an immediate anxiety attack. Manufacturer claims that it is not psychologically addicting and may be used long term. The mechanism of action is not known.

such as atenolol or propranol may be effective in many anxiety situations where the main need is to reduce adrenergic stimulation and tachycardia.

has similar activity to barbiturates with a mild euphoria. It was commonly abused during the 60’s and 70’s. It is no longer on the legal market.

was an sedative prone to abuse and is no longer a legal drug.