Ketamine intravenous injection

Ketamine is the only intravenous anesthetic that possesses analgesic properties and produces cardiovascular stimulation. Heart rate, arterial blood pressure, and cardiac output are usually significantly increased. The peak increases in these variables occur 2-4 minutes after intravenous injection and then slowly decline to normal over the next 10-20 minutes. Ketamine produces its cardiovascular stimulation by excitation of the central sympathetic nervous system and possibly by inhibition of the reuptake of norepinephrine at sympathetic nerve terminals. Increases in plasma epinephrine and norepinephrine levels occur as early as 2 minutes after intravenous ketamine and return to baseline levels 15 minutes later. 

A placebo-controlled study in healthy subjects found that pre-treatment with topiramate 50 mg did not affect the reaction time after sub-anaesthetic doses of ketamine (slow intravenous injection of 120 micrograms/kg followed by 500 micrograms/kg over one hour)9... 

A preparation of Ketamine [2-(Chlorophenyl)-2-(methylamino) cyclohexanone, C23HjgClNO, an anesthetic agent] in an OAV/O multiple emulsion for prolonged drug release was formulated and evaluated. Ketamine is used as a short-acting anesthetic in humans and in some animal species (90). Ketamine is poorly bound to plasma proteins and has a half-life of approximately 4 h following intravenous injection. 

Ketamine has also been studied as an adjuvant to lidocaine intravenous regional anesthesia for hand surgery in 40 patients who received ketamine 0.1 mg/kg either as an adjuvant to the lidocaine or as an intravenous injection [26 ]. There were no significant differences in tourniquet pain or opiate requirements, either intraoperatively or during the recovery period. There were no difference in the incidence of psychotomimetic effects and satisfaction was high in both groups. The authors felt that it would be unethical to include a control group, as ketamine has already been shown to be superior to placebo. However, this makes the conclusions hard to interpret. 

Ketamine is most commonly sold to pharmacies and veterinary clinics in a clear liquid form (Figure 6.1). Illegal users of ketamine inject the drug intravenously or intramuscularly, mix it into a drink, or dip tobacco or marijuana cigarettes into the liquid prior to smoking them. Ketamine liquid is colorless, odorless, and tasteless. This liquid can be easily converted to a white powder by allowing the liquid to evaporate and then collecting the powder residue. This powder can also be mixed into drinks, snorted, or smoked. A typical dose of ketamine costs 20- 25 on the street. 

The chemical structure of ketamine is similar to that of the potent psychedelic PCP (Figure 6.2). Not surprisingly, ketamine produces many psychedelic effects that are similar to those produced by PCP. However, ketamine s effects are much shorter in duration—a trip on ketamine may last only 30-60 minutes, whereas a trip on PCP may last several hours. The onset of ketamine s actions is quite rapid (i.e., within minutes), especially if snorted or injected intravenously. 

Substances from different chemical classes suspend consciousness when given intravenously and can be used as injectable anesthetics (B). Unlike inha-lational agents, most of these drugs affect consciousness only and are devoid of analgesic activity (exception ketamine). The effect cannot be ascribed to nonselective binding to neuronal cell membranes, although this may hold for propofol... 

The technique typically involves the use of intravenous midazolam for premedication (to provide anxiolysis, amnesia, and mild sedation) followed by a titrated, variable-rate propofol infusion (to provide moderate to deep levels of sedation), and a potent opioid analgesic or ketamine (to minimize the discomfort associated with the injection of local anesthesia and the surgical manipulations). 

Ketamine, a weakly basic compound structurally and pharmacologically similar to phencyclidine, is utilized in the U.S. to induce anesthesia.1 It is available in solution for intravenous or intramuscular injection. Since the drug is pharmacologically similar to PCP it has the potential of producing hallucinogenic effects and, therefore, in recent years has become a drug of abuse. 

Ketamine is a compound with a molecular structure similar to that of phencyclidine (Figure 4.2). The pharmaceutical versions of ketamine are clear, colorless liquids available in varying concentrations of 10,50, and 100 milligram/milliliter solutions (Figure 4.3). Many recreational users inject this liquid intramuscularly or intravenously. It is the liquid formulation that is used as a date rape drug. Liquid ketamine, which is clear and colorless, can easily be slipped into a drink without being detected. 

Ketamine is a close relative ot PCP producing very siTnilar eftects. It is a legal prescription drug intended for use as an anesthetic. Ketamine comes in small bottles as a solution to be injected into patients, either intravenously or intramuscularly. 

A controlled study in 100 women showed that pretreatment with intravenous ketamine 10 mg reduced the incidence of injection pain from 84 to 26% of patients (25). 

Ketamine typically is administered intravenonsly bnt also is effective by intramnscnlar, oral, and rectal rontes. The indnc-tion doses are 0.5 to 1.5 mg/kg IV, 4 to 6 mg/kg IM, and 8 to 10 mg/ml. Onset of action after an intravenous dose is similar to that of the other parenteral anesthetics, but the duration of anesthesia of a single dose is longer. For anesthetic maintenance, ketamine occasionally is continued as an infusion (25 to 100 (tg/kg per minute). Ketamine does not elicit pain on injection or true excitatory behavior as described for methohexital, although involuntary movements prodnced by ketamine can be mistaken for anesthetic excitement. 

Ketamine typically is administered intravenously but also is effective by intramuscular, oral, and rectal routes. Ketamine does not elicit pain on injection or true excitatory behavior as described for methohexital, although involuntary movements produced by ketamine can be mistaken for... 

Ketamine is a rapidly acting anesthetic and analgesic. It can be given intravenously, intramuscularly, nasally, orally, rectally, epidurally, spinally, and topically. The initial anesthetic response if given intravenously is seen after 30-40 seconds, while a response after intramuscular administration is seen after 3-4 minutes. Nasal administration results in a response after 8-12 minutes. Analgesic effects after intramuscular, oral, and epidural injection are 10-15, within 30, and within 15-30 minutes, respectively. 

Bioavailability of ketamine is 90-93% after intramuscular injection, 16% after oral administration, and 77% after epidural injection. Protein binding of ketamine is 47%, and it is initially distributed to highly perfused tissues such as brain, heart, and the lungs. There the concentration can reach up to five times the plasma concentration. Redistribution is similar to thiopental. The distribution half-life after intravenous administration is 7 tol7 minutes, and the volume of distribution is 2 to 3 L/kg. 

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