Opioid analgesics concentrations

Hypoventilation is defined as a reduction in the rate and depth of breathing. Inadequate ventilation results in hypoxemia, or a decrease in the concentration of oxygen in the arterial blood. Hypoventilation may be induced inadvertently by various pharmacological agents, including opioid analgesics such as morphine. These medications cause hypoventilation by way of their effects on the respiratory centers in the brainstem. Doses of... 

The state-of-the-art approach to controlled release opioid therapy is to provide formulations which exhibit zero order pharmacokinetics and have minimal peak to trough fluctuation in opioid levels with repeated dosing. This zero order release provides very slow opioid absorption, and a generally flat serum concentration curve over time. A flat serum concentration is generally considered to be advantageous because it would in effect mimic a steady-state level where efficacy is provided but side effects common to opioid analgesics are minimized. 

Hydromorphone Hydrochloride Formulations containing hydromorphone with either minocycline hydrochloride or tetracycline hydrochloride were found incompatible and manifest as a color change from pale yellow to light green. Concentration-dependent incompatibilities are reported in formulations containing hydromorphone hydrochloride with dexamethasone sodium or phosphate,59 and fluorouracil.60 Visual incompatibility, such as haziness or precipitation, developed 4 hours after mixing thiopentone sodium and hydromorphone hydrochloride.61 Dependence, withdrawal, and interactions are similar to those of opioid analgesics. 

Oxaprozin Concomitant administration of oxaprozin with opioid analgesics gives false results for the concentration of benzodiazepines. Phenytoin and correct method should be chosen for the analysis of these drugs.76-78... 

Salmempera et al. (1992) studied in dogs the potency of remifentanil, a short acting opioid analgesic, which is used as anesthetic adjunct by variable-rate infusion. Enfluorane minimal alveolar concentration was measured by the tail-clamp method in dogs before and after sequential infusion of various doses of remifentanil. The plasma concentration causing a 50% reduction of enfluorane minimal alveolar concentration was determined. 

Current anesthesia protocols usually include several agents in combinations that vary according to the depth of anesthesia required for specific procedures. Inhalational anesthetics, which include nitrous oxide and six halogenated hydrocarbons, have varying potency in proportion to their lipid solubilities. MAC value, a measure of anesthetic potency, is defined as the minimal alveolar anesthetic concentration (% of inspired air) at which 50% of patients do not respond to a surgical stimulus. MAC values are additive, lower in elderly patients, and lower in the presence of opioid analgesics and sedative hypnotics. 

Discontinuation - Upon system removal, it takes 17 hours or more for the fentanyl serum concentration to fall by 50% after system removal. Titrate the dose of the new analgesic based on the patient s report of pain until adequate analgesia has been attained. For patients requiring discontinuation of opioids, a gradual downward titration is recommended because it is not known at what dose level the opioid may be discontinued without producing the signs and symptoms of abrupt withdrawal. 

Sufentanyl was the selected opioid because it is a very powerful analgesic and could be formulated in a tailor-made high-concentration solution enabling the release of effective doses of drug throughout a 3 months period despite the small capacity of approximately 155 pi filling... 

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