Fospropofol disodium, a water-soluble prodrug of the intravenous anesthetic propofol (2,6-diisopropylphenol)

Fospropofol disodium versus propofol for long-term sedation during invasive mechanical ventilation: A pilot randomized clinical trial

STUDY OBJECTIVE

Fospropofol disodium is a propofol prodrug that is water-soluble and has a reduced risk of bacterial contamination and hypertriglyceridemia compared with propofol. Prior to implementing a large randomized trial, we investigated the feasibility, initial efficacy, and safety of fospropofol disodium compared with propofol in long-term mild-to-moderate sedation in intensive care units (ICUs).

DESIGN

Single-centered, prospective, unblind, randomized, parallel-group clinical trial.

SETTING

The general ICU of university-affiliated teaching hospital.

PATIENTS

Adult patients (n = 60) expected to have mechanical ventilation for >24 h were enrolled and randomly assigned to the fospropofol or propofol group.

INTERVENTIONS

The fospropofol group received continuous fospropofol disodium infusions and the propofol group received continuous propofol infusions. The sedation goal was a score of -3 to 0 on the Richmond Agitation and Sedation Scale (RASS).

MEASUREMENTS

The primary outcome was the percentage of time spent in the target sedation range without rescue sedation. Safety outcomes were based on adverse events. Blood samples were collected to measure formate concentration in plasma.

MAIN RESULTS

The median dose was 4.33 (IQR, 3.08-4.94) mg/kg/h in the fospropofol group and 1.96 (IQR, 1.44-2.94) mg/kg/h in the propofol group. The median percentage of time spent in the target RASS range without rescue sedation was identical in both groups, with 83.33% (IQR, 74.43%-100.00%) in the fospropofol group and 83.33% (IQR, 77.45%-100.00%) in the propofol group (p = 0.887). At least one adverse event was identifed in 23 (76.7%) fospropofol patients and 27 (90.0%) propofol patients. The most common adverse events were tachycardia and hypotension. No paresthesia, catheter-related bloodstream infection or propofol infusion syndrome in both groups was reported. Three patients in the fospropofol group had mild hypertriglyceridemia, and nine patients in propofol group had hypertriglyceridemia (mild in eight patients and moderate in one patient) (10% versus 30%, p = 0.104). The formate concentration in plasma was very low, and no significant difference was identified at any time point between the two groups.

CONCLUSIONS

Fospropofol disodium appears to be a feasible, effective and safe sedative for patients receiving invasive mechanical ventilation with long-term sedation.

Propofol-Associated Urine Discoloration: Systematic Literature Review

INTRODUCTION

Propofol occasionally induces a green or pink-cloudy urine discoloration. A lesser-known effect is green discoloration of hair, milk, liver, or stool. We aimed to gain insight into the features of these disturbances.

METHODS

The terms ("propofol" OR "fospropofol") AND ("green" OR "pink" OR "cloudy" OR "pink-cloudy") were searched in Excerpta Medica, MEDLINE/PubMed®, and Web of Sciences databases, with no language limit, from inception up to February 2023 (CRD4202236804). Articles reporting individually documented cases were retained, and data were extracted using a checklist.

RESULTS

Seventy-seven original reports documented 95 cases (including 13 subjects ≤18 years of age). Completeness of reporting was satisfactory in 33, good in 35, and excellent in 27 cases. Propofol-associated green urine discoloration was observed in 54 patients. In most instances (n = 21, 39%), propofol was given for ≥24 h. Sometimes, however, the urine discoloration developed after propofol for ≤3 h (n = 12, 22%). Propofol-associated urine discoloration was usually observed during the administration of this agent, but it was at times (n = 11) first recognized ≥3 h after propofol discontinuation. The duration of green urine discoloration was usually ≤24 h after stopping propofol. Propofol-associated green urine discoloration was never associated with worsening kidney function. A pink-cloudy urine discoloration was observed in 32 subjects with an acidic urine pH and increased uric acid excretion given propofol for ≤24 h. A stage I acute kidney injury was observed in 2 cases (6.3%) of propofol-associated pink-cloudy urine discoloration. Nine cases of non-urinary green discoloration were observed: hair (n = 4), breast milk (n = 1), liver (n = 1), stool (n = 1).

CONCLUSION

Propofol is sometimes associated with a green (benign) or pink-cloudy (occasionally associated with mild acute kidney injury) urine discoloration. Rarely, non-urinary green discoloration has been reported.

Advances in Analgosedation and Periprocedural Care for Gastrointestinal Endoscopy

The number and complexity of endoscopic gastrointestinal diagnostic and therapeutic procedures is globally increasing. Procedural analgosedation during gastrointestinal endoscopic procedures has become the gold standard of gastrointestinal endoscopies. Patient satisfaction and safety are important for the quality of the technique. Currently there are no uniform sedation guidelines and protocols for specific gastrointestinal endoscopic procedures, and there are several challenges surrounding the choice of an appropriate analgosedation technique. These include categories of patients, choice of drug, appropriate monitoring, and medical staff providing the service. The ideal analgosedation technique should enable the satisfaction of the patient, their maximum safety and, at the same time, cost-effectiveness. Although propofol is the gold standard and the most used general anesthetic for endoscopies, its use is not without risks such as pain at the injection site, respiratory depression, and hypotension. New studies are looking for alternatives to propofol, and drugs like remimazolam and ciprofol are in the focus of researchers' interest. New monitoring techniques are also associated with them. The optimal technique of analgosedation should provide good analgesia and sedation, fast recovery, comfort for the endoscopist, patients' safety, and will have financial benefits. The future will show whether these new drugs have succeeded in these goals.

New sedatives and analgesic drugs for gastrointestinal endoscopic procedures

Procedural sedation has become increasingly common in endoscopy. Sedatives and analgesics induce anxiolysis and amnesia. In addition, an appropriate level of sedation is necessary for safe procedures including therapeutic endoscopy. Midazolam and propofol are the most commonly used drugs in sedative endoscopy. In recent years, the need to ascertain the safety and effectiveness of sedation has increased in practice. Therefore, new sedatives and analgesic drugs for optimal sedative endoscopy, have recently emerged. This article reviews the characteristics of sedatives and analgesics, and describes their clinical use in gastrointestinal endoscopy.

Nanostructured Lipid Carrier of Propofol: a Promising Alternative to Marketed Soybean Oil-Based Nanoemulsion

Nanostructured lipid carrier (NLC) of propofol was formulated using hot emulsification-probe sonication method for improvising its parenteral delivery by reducing pain on injection and risk of microbial contamination. The formulated NLC was optimized using central composite design and evaluated for particle size, zeta potential, morphology, free propofol concentration, hemocompatibility, stability, pain on injection, in vivo anesthetic activity, pharmacokinetics, and antimicrobial effectiveness in comparison to the marketed formulation. Optimized NLCs exhibited globule size, less than 200 nm, and zeta potential - 24.1 mV, indicating its stability. TEM images confirmed the spherical shape and nanosize (200 nm) of optimized NLCs. Free propofol concentration was also found to be 40% lesser than marketed formulation. Optimized NLC was found to be non-hemolytic. Rat paw-lick study showed that propofol NLC was significantly less painful compared to the marketed formulation. Anesthetic potential and pharmacokinetics of optimized NLCs were found to be similar to that of the marketed formulation. NLC was found stable in long-term storage under room temperature. Antimicrobial effectiveness study showed that propofol NLC suppressed microbial growth to a greater extent as compared to the marketed formulation. Hence, the developed propofol NLCs appeared to be clinically useful as a potential carrier for propofol delivery.

Metabolic Profiles of Propofol and Fospropofol: Clinical and Forensic Interpretative Aspects

Propofol is an intravenous short-acting anesthetic widely used to induce and maintain general anesthesia and to provide procedural sedation. The potential for propofol dependency and abuse has been recognized, and several cases of accidental overdose and suicide have emerged, mostly among the health professionals. Different studies have demonstrated an unpredictable interindividual variability of propofol pharmacokinetics and pharmacodynamics with forensic and clinical adverse relevant outcomes (e.g., pronounced respiratory and cardiac depression), namely, due to polymorphisms in the UDP-glucuronosyltransferase and cytochrome P450 isoforms and drugs administered concurrently. In this work the pharmacokinetics of propofol and fospropofol with particular focus on metabolic pathways is fully reviewed. It is concluded that knowing the metabolism of propofol may lead to the development of new clues to help further toxicological and clinical interpretations and to reduce serious adverse reactions such as respiratory failure, metabolic acidosis, rhabdomyolysis, cardiac bradyarrhythmias, hypotension and myocardial failure, anaphylaxis, hypertriglyceridemia, renal failure, hepatomegaly, hepatic steatosis, acute pancreatitis, abuse, and death. Particularly, further studies aiming to characterize polymorphic enzymes involved in the metabolic pathway, the development of additional routine forensic toxicological analysis, and the relatively new field of ‘‘omics” technology, namely, metabolomics, can offer more in explaining the unpredictable interindividual variability.

[Fospropofol: A new prodrug of propofol]

The development of new propofol formulations has advanced rapidly in the last ten years with the achievement of the marketing a new prodrug of propofol: fospropofol, pharmacologically different from the original compound. It is a water soluble compound that requires metabolism of the prodrug to propofol, which leads to a time delay between its administration and the appearance of its pharmacological effect. Its pharmacokinetic and pharmacodynamic characteristics are different to the original formula. Due to its formulation it does not cause pain on intravenous injection, does not lead to hyperlipidaemia or excess bacterial growth. Although it is currently unavailable in Spain, it has been approved by the FDA (American Food and Drug Administration) for sedation in controlled care in diagnostic and therapeutic procedures in adults. It must only be administered by personnel qualified to administer anaesthesia, and the patients must be monitored throughout the whole procedure.