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Biomedical subjects

J C Crews

Publications and source records attributed to J C Crews.

8 recordsLinked to original sources
PubMed1991

Stability of methadone hydrochloride in 0.9% sodium chloride injection in single-dose plastic containers.

The stability of methadone hydrochloride in 0.9% sodium chloride injection in flexible polyvinyl chloride containers was studied. Commercially available methadone hydrochloride 20 mg/mL and 25-mL single-dose bags of 0.9% sodium chloride injection were used. Six samples each were prepared at methadone hydrochloride concentrations of 1, 2, and 5 mg/mL. The solutions were stored at room temperature and were not protected from light. Immediately after preparation and after two, three, and four weeks of storage, each of the 18 samples was divided into three aliquots, each of which was analyzed in duplicate for methadone hydrochloride concentration by gas chromatography. There was less than 10% change in methadone hydrochloride concentration in any sample throughout the four-week study period. Methadone hydrochloride at concentrations of 1, 2, and 5 mg/mL prepared in commercially available flexible polyvinyl chloride containers of 0.9% sodium chloride injection and stored at room temperature without deliberate protection from light is stable for at least four weeks.

Drug Packaging↗
PubMed1990

Recovery of morphine from a controlled-release preparation. A source of opioid abuse.

MS-Contin (Purdue-Fredrick, Norwalk, CT) is a controlled-release preparation of morphine sulfate that has demonstrated efficacy in the management of chronic cancer pain problems. It has recently come to the attention of the authors that MS-Contin represents a potential source of opioid abuse through the extraction and intravenous injection of the morphine from this preparation. The authors describe a simple aqueous extraction method that was used to quantitatively determine the extent to which morphine could be obtained from MS-Contin tablets.

Adult↗
PubMed1990

The correlation between predicted and measured patient specific analgesic concentrations after intravenous titration: a guide for initial maintenance requirements with methadone.

The relationship between the analgesic methadone concentrations measured and those predicted using a pharmacokinetic approach were assessed in 22 patients referred for long-term management of severe pain with intravenous methadone. Five milligrams of methadone were administered IV every 10 minutes until the patient reported a visual analog scale (VAS) pain score of less than or equal to 2. Initial maintenance infusion rates were chosen based on the number of 5 mg doses required to produce satisfactory analgesia. Overall, the methadone concentrations predicted using pharmacokinetic modeling were in excellent agreement with those actually measured. Over 95% of the variance in the data was explained using this model (r2 = 0.9704). Using the rapid titration paradigm described here, one can obtain a reasonable estimate of patient specific analgesic (target) concentration as well as initial infusion requirements for methadone.

Humans↗
PubMed1990

Epidural opioid analgesia.

Epidural opioid analgesia has become an important therapeutic technique in the management of acute pain and has been demonstrated to be superior or equal to other parenteral opioid techniques (intramuscular, intravenous, PCA) with less associated sedation and significantly smaller doses of drugs. Beneficial therapeutic effects of epidural opioids as a result of improved analgesia include improvement in pulmonary function, modification of the endocrine-metabolic stress response, improvement in time to ambulation, decreased morbidity, and shorter hospital stay. The epidural administration of opioids is associated with potential side effects and complications, the most serious potential side effect being that of respiratory depression. This, as well as most of the other potential medication-related side effects associated with epidural opioid analgesia, is for the most part also associated with opioid analgesia provided by other routes of administration. These potential problems either occur rarely, or are controllable or preventable with appropriate patient selection and management. The potential benefits to the critical care patient as a result of the superior analgesia and reduced systemic effects associated with epidural opioid analgesia represent distinct medical and economic advantages, compared to conventional analgesic techniques.

Analgesia, Epidural↗
PubMedDate not supplied

Tourniquet pain: the response to the maintenance of tourniquet inflation on the upper extremity of volunteers.

This investigation examined the effect of three factors--tourniquet width, tourniquet inflation pressure, and application of the tourniquet to the left or right extremity--on the intensity of tourniquet pain and duration of tourniquet inflation, as well as the circulatory effects associated with maintenance of inflation of a pneumatic tourniquet on an upper extremity of 12 healthy, unmedicated volunteers. All subjects manifested a time-dependent circulatory response to maintenance of tourniquet inflation, characterized by increases in heart rate and systolic and diastolic blood pressure. The mean duration of tourniquet inflation was 34 +/- 13 minutes (mean +/- SD). No difference was demonstrated with respect to the width of the tourniquet, the tourniquet inflation pressure, or the application of the tourniquet to the left or right extremity on the intensity of pain or the duration of tourniquet inflation.

Arm↗
PubMedDate not supplied

Response to maintenance of tourniquet inflation in a primate model.

Several theories have been proposed, but the etiology and pathway of neural transmission for the sensation of tourniquet pain remain unknown. This study was designed to observe the circulatory response and to measure the stress response markers associated with maintenance of tourniquet inflation in an anesthetized primate model. Eight African Green monkeys (Cercopithecus aethiops) were anesthetized, and heart rate (HR) and systolic and diastolic blood pressure (SBP and DBP) were measured every five minutes. In each animal, a control trial without tourniquet inflation was compared to an experimental trial with tourniquet inflation on the left lower extremity to 300 mmHg for a period of 90 minutes. After maintenance of tourniquet inflation for a period of 30-45 minutes, each animal demonstrated a gradual, progressive increase in HR, SBP and DBP as compared to preinflation baseline values (p less than 0.05). An increase in serum cortisol and plasma norepinephrine was demonstrated to correlate with the circulatory response in this model. The results of this study suggest that the circulatory response to maintenance of tourniquet inflation in this animal model may be mediated by a neurohumoral response to tourniquet pain and that an animal model may be appropriate for further studies into the etiology and neural pathways associated with the sensation of tourniquet pain.

Anesthesia, General↗