Overdosing avoidance

The various barbiturates differ m the time required for the onset of sleep and m the duration of their effects All the barbiturates must be used only m strict accordance with instructions to avoid potentially lethal overdoses Drug dependence m some mdi viduals IS also a problem... 

Patients should always start with the lowest recommended dose and increase slowly to avoid overdosing. Follow-up with the patient is necessary to evaluate whether the dietary supplement is safe and effective. Report any suspected adverse event to FDA s Medwatch, 1-800-FDA-1088. FDA has developed the Special Nutritionals Adverse Event Monitoring System (SN/AEMS), a database of adverse events associated with the use of special nutritional products dietary supplements, infant formulas, and medical foods. ... 

In order to avoid overdosing, estimated lean body mass should be used in obese patients. 

Of greater concern is the safety of the TCAs. Toxic levels of these medications can produce lethal cardiac arrhythmias, seizures, and suppression of breathing. An overdose of a 1-2 week supply of most TCAs is often fatal, a serious consideration when prescribing medication to depressed patients with suicidal thoughts. Children taking imipramine for treatment of ADHD have died from sudden cardiac death consequently, child psychiatrists seldom use TCAs. Likewise, patients with heart disease or seizure disorders are more likely to have dangerous complications from TCAs and should avoid them. 

When treating insomnia without depression, doxepin and amitriptyline (both tricyclic antidepressants) can be administered in low doses (25-100 mg) at bedtime. These antidepressants, however, do have troublesome anticholinergic side effects (dry mouth, constipation, blurred vision, dizziness) and adverse effects on the heart, and they can be lethal if taken in overdose. Because of their effect on heart function, these antidepressants should be avoided in patients with heart problems and administered cautiously, if at all, to those who are already receiving one of any number of newer antidepressants that inhibit the metabolism of the TCAs. 

Determine patient baseline activated partial thromboplastin time (aPTT) prior to initiation of therapy with lepirudin, because lepirudin should not be started in patients presenting with a baseline aPTT ratio of 2.5 or more in order to avoid initial overdosing. 

Conversion from CR tablets to parenteral opioids To avoid overdose, follow conservative dose conversion ratios. For patients receiving high-dose parenteral opioids, a more conservative conversion is warranted. 

Note It is a good general practice to avoid treating the symptoms of use, withdrawal and overdose with other drugs. General support and control are often adequate. On the other hand the use of anticonvulsants should be prompt and the use of other drug supports considered carefully, in relationship to the clinical, psychological and social situation. 

Flumazenil Romazicon) is a benzodiazepine antagonist that specifically reverses the respiratory depression and hypnosis produced by the benzodiazepine receptor agonists. Its block of the amnesic effect of the agonists is less reliable. Flumazenil is particularly useful when an overdose of benzodiazepines has occurred. It is also employed when a benzodiazepine has been used to produce conscious sedation and rapid recovery of psychomotor competency is desirable. To avoid resedation, flumazenil may require administration by intravenous infusion. 

Increasing the inspired tension of an anesthetic gas above the maintenance tension (i.e., near the MAC value) is also an effective means of quickly establishing effective alveolar tension. This maneuver, frequently referred to as overpressure, parallels the concept of loading dose. As the desired depth of anesthesia or level of alveolar tension is achieved, the delivered tension of anesthetic must be returned to the maintenance (MAC) level to avoid overdosing the patient. 

Despite impressions to the contrary, MAOIs are generally well tolerated if patients observe the restricted diet and avoid medications that contain sympathomimetic amines. Adverse effects are rarely a treatment-limiting problem with the exception of hypotension. MAOIs also fall between TCAs and SSRIs in terms of overdose risk. Major toxic reactions to MAOIs are uncommon but require immediate discontinuation and symptomatic treatment. 

Compared to barbiturates, benzodiazepines are relatively safe medications that produce little tolerance and suppression of REM sleep, and benzodiazepine overdoses are much less common. However, benzodiazepines are not without unwanted side effects. As mentioned above, longer-acting benzodiazepines can produce residual drowsiness, grogginess, and weakness the next day (benzodiazepines are also muscle relaxants). Benzodiazepines can produce rebound insomnia, in which the person experiences significant insomnia after he or she stops taking the medication. This is particularly true with benzodiazepines that have short half-lives. To avoid this, the patient should never stop cold turkey rather, the dosage should be slowly tapered off over several days to a week. 

If salvinorin is inhaled as multiple inhalations of leaf smoke or vapor one could reasonably expect to pass out before he/she could take a lethal overdose. But significantly, nothing is known about the toxic effects of smoking truly massive single bolus doses of pure salvinorin, such a practice might be quite dangerous, and should certainly be avoided. 

When a 45-year-old man with severe lithium-induced diabetes insipidus developed hyperosmolar, nonketotic hyperglycemia, it was suggested that poorly controlled diabetes mellitus may have contributed to the polyuria (684). Prior contact with a female patient who had developed hyperosmolar coma secondary to lithium-induced diabetes insipidus (685) allowed physicians 4 years later to treat her safely after a drug overdose and a surgical procedure, by avoiding intravenous replacement fluids with a high dextrose content (despite stopping lithium several years earlier, the patient continued to put out 10 liters of urine daily) (686). 

Theophylline, an asthma controller, has a very low safety/therapeutic ratio. One of the first clinical application for HPLC was to titrate theophylline levels in patient blood to avoid toxic overdoses. Blood levels can be controlled by assay at UV, 270 nm, on a C18 column in 7% An/water at pH 4.0 with phosphate buffer. 

The instructions on how and when to take medications, the duration of therapy, and the purpose of the medication must be explained to each patient by the physician and by the pharmacist. (Neither should assume that the other will do it.) Furthermore, the drug name, the purpose for which it is given, and the duration of therapy should be written on each label so that the drug may be identified easily in case of overdose. An instruction to "take as directed" may save the time it takes to write the orders out but often leads to noncompliance, patient confusion, and medication error. The directions for use must be clear and concise to avoid toxicity and to obtain the greatest benefits from therapy. 

The drug is metered to the body slowly over a long period therefore, the problem of overdosing and underdosing associated with conventional periodic medication is avoided. 

A review of the use of process and treatment plant chemicals is required to identify those that have the potential to contribute to toxicity. For each chemical the following should be determined i) availability of current MSDS and toxicity test data for species of interest, ii) purpose and volume used (volumes used are typically available from the supplier), iii) whether the amount can be reduced or reused, iv) whether less toxic alternatives are available, and v) if it is possible to avoid discharge of the chemical (U.S. EPA, 1989 1999). Even a slight overdosing of effluent treatment chemicals (e.g., polymers, chlorine) could result in potentially toxic concentrations in the final effluent, since these chemicals do not have the... 

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