Medical uses of barbiturates

Finally barbiturates are found in combination products for analgesia or pain relief. The two most common are Fioricet and Fiorinal, although others exist. 

Class Generic Drug Name Brand Name Duration of Action 

Combination Analgesics acetaminophen/ caffeine and butalbital Fioricet Varies 

CURRENT MEDICAL USES OF BARBITURATES Sedative/Hypnotics 

Barbiturates are still used as sedative/hypnotic agents (see Chapter 3), but they have been largely replaced by benzodiazepines for treatment of anxiety and insomnia (difficulty sleeping). Barbiturates are still used occasionally, but benzodiazepines have proven to be much safer and have less risk of accidental overdose. 

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The CNS depressants include barbiturates, nonbarbiturate sedatives, and the benzodiazepines. As the medical use of barbiturates decreased, primarily because of their high addiction liability and the danger of acute lethality, the use of the benzodiazepine anxiolytics increased. The most commonly abused barbiturates are secobarbital, pentobarbital, and amobarbital. Pheno-barbital is not generally abused, because of its slow onset of action. The most commonly abused anxiolytics include diazepam, chlordiazepoxide, midazolam, lo-razepam, and flurazepam. These drugs are readily attainable from illicit sources. 

One major reason for the movement away from the medical use of barbiturates involves tolerance and dependence. Tolerance develops fairly rapidly to many effects of the barbiturates. Whereas a given dose may be effective at inducing sleep for a while, if the drug is used regularly the patient soon may require a higher dose in order to sleep. If doses escalate too much and regular use persists, the patient will experience an abstinence syndrome when he or she attempts to withdraw from barbiturates. The symptoms of the barbiturate withdrawal syndrome are similar to those of alcohol— shakes, perspiration, confusion, and in some cases full-blown delirium tremens (DTs) (see Chapter 9)—but convulsions and seizures are more likely to occur in barbiturate... 

Use of barbiturates combined with many other medications has been reported to alter the effects of barbiturates or the other drugs. Most of these drug interactions have been specifically reported with the barbiturate phenobarbital. There are... 

Many people became dependent on barbiturates even though the drugs were used only under medical supervision. Suppose someone is in crisis—say, after the death of a spouse or other loved one. A physician may prescribe a sleeping pill to help the person rest during the crisis. After a tew weeks the patient may feel emotionally ready to sleep without the drug—and indeed may be. But the first night he or she attempts to sleep without the barbiturate, the person may have a great deal of trouble because one of the features of barbiturate withdrawal is rebound insomnia (Mendelson, 1980). That is, after the chronic use of barbiturates, abstinence produces insomnia even in someone who was untroubled with insomnia previously. 

In addition to their prescribed medical uses, many barbiturates have also found widespread illegal use as street drugs. Each barbiturate comes as a tablet of regulated size, shape, and color, and their street names often mimic those colors. Although still used today, most barbiturates have been replaced by safer, more potent alternatives with markedly different structures. 

Pharmacological Profiles of Anxiolytics and Sedative—Hypnotics. Historically, chemotherapy of anxiety and sleep disorders rehed on a wide variety of natural products such as opiates, alcohol, cannabis, and kawa pyrones. Use of various bromides and chloral derivatives ia these medical iadications enjoyed considerable popularity early ia the twentieth century. Upon the discovery of barbiturates, numerous synthetic compounds rapidly became available for the treatment of anxiety and insomnia. As of this writing barbiturates are ia use primarily as iajectable general anesthetics (qv) and as antiepileptics. These agents have been largely replaced as treatment for anxiety and sleep disorders. 

Dependence on barbiturates has declined in recent years as physicians have substituted benzodiazepines for the treatment of many of the conditions for which barbiturates were formerly used. Clinicians will still see cases of abuse and dependence among medical patients receiving barbiturates or barbirurate combination products (e.g., Fiorinal) and in substance abusers (Silberstein and McCrory 2001). 

Other sedative-hypnotic medications, such as barbiturates, may play a useful role in severe withdrawal from this group of drugs. For example, in a case series of GBL withdrawal, use of intravenous pentobarbital in the range of 1-2 mg/kg/hour lowered the total requirement for intravenous lorazepam (Sivilotti et al. 2001). Antipsychotic medications are often used to reduce psychotic agitation. However, because antipsychotic medications lower the seizure threshold and may contribute to loss of central control of temperature leading to hyperthermia or neuroleptic malignant syndrome (NMS), they are not indicated as first-line medications for GHB withdrawal delirium (Dyer and Roth 2001 McDaniel and Miotto 2001 Sharma et al. 2001). If anti-... 

Schedule III—The drug or other substance has (1) a potential for abuse less than the drugs or other substances in Schedules I and II, (2) a currently accepted medical use in treatment in the United States, and (3) abuse of the drug or other substance may lead to moderate or low physical dependence or high psychological dependence. Examples ketamine, anabolic steroids, some barbiturates. 

Nonbarbiturates. After the introduction of the barbiturates, there was little progress in the medical treatment of anxiety until meprobamate (Equanil, Miltown) was introduced in 1950. Soon after its introduction, a series of similar medicines entered the market, including carisoprodol (Soma), glutethimide (Doriden), methaqualone (Qaalude, Sopor), methyprylon (Noludar), and ethchlorvynol (Placidyl). These medications have all been used to treat anxiety, insomnia, and muscle spasms. 

Historically, the treatment of alcohol use disorders with medication has focused on the management of withdrawal from the alcohol. In recent years, medication has also been used in an attempt to prevent relapse in alcohol-dependent patients. The treatment of alcohol withdrawal, known as detoxification, by definition uses replacement medications that, like alcohol, act on the GABA receptor. These medications (i.e., barbiturates and benzodiazepines) are cross-tolerant with alcohol and therefore are useful for detoxification. By contrast, a wide variety of theoretical approaches have been used to reduce the likelihood of relapse. This includes aversion therapy and anticraving therapies using reward substitutes and interference approaches. Finally, medications to treat comorbid psychiatric illness, in particular, depression, have also been used in attempts to reduce the likelihood of relapse. 

Benzodiazepines. Safer than the barbiturates but acting in a similar manner, the benzodiazepines have largely replaced barbiturates since their introduction in the 1960s. Other uses of benzodiazepines include treatment for epilepsy, alcohol withdrawal, several anxiety disorders, agitation, and impulsivity, as muscle relaxants, and as conscious sedation during certain medical procedures. 

Meprobamate was proposed before the introduction of benzodiazepines into medical practice. The exact mechanism of action of this drug is not known however, its effects on the CNS are more similar to the effects barbiturates than to benzodiazepines, but with shorter-lasting action. After the introduction of benzodiazepines into practice, the use of this drug became significantly less. Meprobamate is used primarily as a daytime anxiolytic in treating conditions of anxiety associated with everyday, usual, and common stress. Synonyms for this drug are cypron, equanil, stenzol, mepron, miltaun, and others. 

Effects of pH on urinary drug elimination may have important applications in medical practice, especially in cases of overdose. For example, one can enhance the elimination of a barbiturate (a weak acid) by administering bicarbonate to the patient. This procedure alka-linizes the urine and thus promotes the excretion of the now more completely ionized drug. The excretion of bases can be increased by making the urine more acidic through the use of an acidifying salt, such as ammonium chloride. 

Coadministration of beta-blockers can potentiate rebound hypertension upon discontinuation of medications, and it is therefore recommended that the beta-blocker be withdrawn before the tt2 agonist (Physicians Desk Reference, 2001). Tricyclic antidepressants may also produce changes in sinus node and AV conduction, and it is recommended that they be used cautiously in combination with tt2 agonists (Physicians Desk Reference, 2001). However, in child psychiatric practice, there has been debate about whether there are adverse interactions related to concomitant use of tricyclics and tt2 agonists. Finally, the tt2 agonists may potentiate the effects of CNS depressants (e.g., barbiturates) or other medications that produce sedation, so lower doses of each may be warranted. 

Aside from the bromides, phenobarbital is the oldest of the currently available antiseizure drugs. Although it has long been considered one of the safest of the antiseizure agents, the use of other medications with lesser sedative effects has been urged. Many consider the barbiturates the drugs of choice for seizures only in infants. 

The depressant effect of barbiturates is often sought by persons who are self-medicating for amdety-related problems or insomnia. Drugs of the benzodiazepine family (Librium, Valium, and Xanax) are also legitimately prescribed for the treatment of anxiety as well as muscle spasms or convulsions. However, doctors and patients must be careful because prolonged or excessive use can lead to dependence. Illegal use often involves forged prescriptions or the cooperation of illicit doctors. 

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