Lorazepam respiratory

Lorazepam (Ativan) 0.5-2 mg prior to chemotherapy Most common Sedation, amnesia Rare Respiratory depression, ataxia, blurred vision, hallucinations, paradoxical reactions (weeping, emotional reactions)... 

Benzodiazepines, especially lorazepam, are used to prevent and treat CINV.5,10 Lorazepam is thought to prevent input from the cerebral cortex and limbic system from reaching the central vomiting center in the brain stem.10 Sedation and amnesia are common side effects. Respiratory depression can occur with high doses or when other central depressants such as alcohol are combined with benzodiazepines. 

Midazolam Midazolam is water-soluble and can be administered intravenously, intramuscularly,13 buccally,14,15 and nasally.16,17 At physiologic pH, it becomes more lipophilic and can diffuse into the CNS. Compared to diazepam and lorazepam, it has fewer effects on the respiratory and cardiovascular systems. Its short half-life requires that it be re-dosed... 

Lorazepam (Ativan) 0.1 mg/kg 2 mg/minute (IVP) N/A Hypotension, respiratory depression May be longer-acting than diazepam... 

Benzodiazepines are the evidence-based treatment of choice for uncomplicated alcohol withdrawal.17 Barbiturates are not recommended because of their low therapeutic index due to respiratory depression. Some of the anticonvulsants have also been used to treat uncomplicated withdrawal (particularly car-bamazepine and sodium valproate). Although anticonvulsants provide an alternative to benzodiazepines, they are not as well studied and are less commonly used. The most commonly employed benzodiazepines are chlordiazepoxide, diazepam, lorazepam, and oxazepam. They differ in three major ways (1) their pharmacokinetic properties, (2) the available routes for their administration, and (3) the rapidity of their onset of action due to the rate of gastrointestinal absorption and rate of crossing the blood-brain barrier. 

Following acute exposure to cyclodiene organochlorine pesticides, seizures and respiratory depression may occur (Ellenhom 1988 Proctor et al. 1988). Benzodiazepines (e.g., diazepam or lorazepam) or other anticonvulsant medications (e.g., phenobarbital) have been commonly used to control seizures (Ford 1993). Organochlorines may sensitize the myocardium to the proarrhythmic effects of adrenergic amines, potentially resulting in initiation of ventricular fibrillation (TOMES 1994). 

Benzodiazepines—including diazepam, lorazepam, and midazolam—are used intravenously in anesthesia (see Chapter 25), often in combination with other agents. Not surprisingly, benzodiazepines given in large doses as adjuncts to general anesthetics may contribute to a persistent postanesthetic respiratory depression. This is probably related to their relatively long half-lives and the formation of active metabolites. However, such depressant actions of the benzodiazepines are usually reversible with flumazenil. 

The benzodiazepine antagonist flumazenil can be used to accelerate recovery when excessive doses of intravenous benzodiazepines are administered (especially in elderly patients). However, reversal of benzodiazepine-induced respiratory depression is less predictable. The short duration of action (< 90 minutes) of flumazenil may necessitate multiple doses to prevent recurrence of the CNS depressant effects of the longer-acting benzodiazepines (eg, lorazepam, diazepam). 

A 34-year-old woman with a history of renal insufficiency induced by long-term use of cocaine developed respiratory failure and was intubated and sedated with intravenous lorazepam (65 mg, 313 mg, and 305 mg on 3 consecutive days). After 2 days she had a metabolic acidosis, with hyperlactatemia and hyperosmolality. Propylene glycol, a component of the lorazepam intravenous formulation, was considered as a potential source of the acidosis, as she had received more than 40 times the recommended amount over 72 hours. Withdrawal of lorazepam produced major improvements in lactic acid and serum osmolality. 

Lorazepam is less lipophilic than diazepam and there is evidence that it has a longer duration of anticonvulsant action than diazepam after intravenous administration. This could be due to the fact that diazepam is more rapidly removed from the brain compartment than lorazepam, which limits its duration of antiepileptic activity. In practice, when diazepam is used to control status epilepticus it is often necessary to continue treatment with diphenylhydantoin, which has a longer duration of action in the brain. The principal hazards of benzodiazepines when given intravenously include respiratory depression and hypotension. Diazepam may be administered rectally, its ease of absorption leading to peak plasma levels within about 10 minutes. 

The use of intravenous benzodiazepines administered by paramedics for the treatment of out-of-hospital status epilepticus has been evaluated in a double-blind, randomized trial in 205 adults (54). The patients presented either with seizures lasting 5 minutes or more or with repetitive generalized convulsive seizures, and were randomized to receive intravenous diazepam 5 mg, loraze-pam 2 mg, or placebo. Status epilepticus was controlled on arrival at the hospital in significantly more patients taking benzodiazepines than placebo (lorazepam 59%, diazepam 43%, placebo 21%). The rates of respiratory or circulatory complications related to drug treatment were 11% with lorazepam, 10% with diazepam, and 23% with placebo, but these differences were not significant. 

The safety of benzodiazepines in neonates has been assessed in a retrospective chart review of 63 infants who received benzodiazepines (lorazepam and/or midazolam) as sedatives or anticonvulsants (57). Five infants had hypotension and three had respiratory depression. In all cases of respiratory depression, ventilatory support was initiated or increased. Significant hypotension was treated with positive inotropic drugs in two cases. Thus, respiratory depression and hypotension are relatively common when benzodiazepines are prescribed in these patients. However, both depression and hypotension could also have been due to the severe underlying illnesses and concomitant medications. Matched controls were not studied. 

Diazepam produces less sedation in cigarette smokers, and higher (not lower, as stated in SEDA-20) doses may be required for the same sedative or anxiolytic effect. Owing in part to its continued widespread use, several unusual adverse effects of diazepam continue to be reported. These include cases of urinary retention and compartment syndrome, which are not explicable by its pharmacology. On the other hand, accumulation of diazepam and attendant complications of obtundation and respiratory depression may be understood in terms of its long half-life, particularly in elderly people and medically ill patients. Caution about the intravenous use of diazepam comes from a study that showed cardiac dysrhythmias (mainly ventricular extra beats) in a quarter of oral surgery patients midazolam and lorazepam were much safer (1). 

Patients receiving intravenous benzodiazepines must be monitored for respiratory depression, which may demand artificial ventilation during intensive treatment. Diazepam may cause more respiratory depression than lorazepam at equieffective dosages (SEDA-20, 59) and is contraindicated in neonates for this reason and because it produces unacceptably prolonged sedation (9). 

BZDs OPIOIDS 1. t sedation with BZDs 2. Respiratory depressant effect of morphine is antagonized by lorazepam. 1. Additive effect both drugs are sedatives 2. Uncertain 1. Closely monitor vital signs during co-administration 2. Although this effect may be considered to be beneficial, it should be borne in mind if the combination of an opioid and BZD is used for sedation for painful procedures... 

Respiratory depression may occur when loxapine is combined with lorazepam... 

A 57-year-old man with a history of alcohol abuse developed acute respiratory failure and was given lorazepam up to 18 mg/hour during alcohol withdrawal (17). On day 43 (cumulative intravenous lorazepam dose 4089 mg, containing about 220 ml of polyethylene glycol 400), he developed oliguric acute tubular necrosis with proteinuria and granular casts. 

E Respiratory depression is seen with benzodiazepines (lorazepam, diazepam) and with barbiturates (phenobarbital, pentobarbital). Both classes are associated with sedation, somnolence, and respiratory depression. However, both phenytoin and fos-phenytoin do not affect respiratory rate. 

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