Toxic Rep Ser. 2000 Aug;56:1-G14.ations in rats administered a single gavage dose of carisoprodol in corn oil also increased with increasing dose. In the carisoprodol in corn oil mouse study, two females each in the vehicle control and 75 mg/kg groups and one female each in the 150 and 600 mg/kg groups were accidentally killed; all males survived to the end of the study. One male and one female administered 1,600 mg/kg carisoprodol in 0.5% methylcellulose died; seven mice were accidentally killed. The mean body weights and body weight gains of mice administered carisoprodol in corn oil were generally similar to those of the vehicle controls. The final mean body weights and body weight gains of all groups of males and females administered carisoprodol in 0.5% methylcellulose were significantly less. Clinical findings in the carisoprodol in corn oil study included lethargy, ataxia, tremors, and prostration in male and female mice. Ataxia, lethargy, convulsions, and prostration were observed in all dosed groups of males and females administered carisoprodol in 0.5% methylcellulose. In the carisoprodol in corn oil study, liver weights were significantly greater in males administered 300 mg/kg or greater and in females administered 150 mg/kg or greater than in the vehicle controls. In the carisoprodol in corn oil study, no gross or microscopic lesions were considered related to carisoprodol administration. Minimal to mild centrilobular hypertrophy was observed in the liver of all dosed groups of males and in females in the 1,200 and 1,600 mg/kg groups in the carisoprodol in 0.5% methylcellulose study. The testis weights of males administered 1,200 mg/kg carisoprodol in corn oil were significantly less than those of the vehicle controls; the sperm motility of males in this group was also significantly less than that of the vehicle controls. There were no significant differences in vaginal cytology parameters between dosed and vehicle control females. At the end of the carisoprodol in corn oil study, the concentration of carisoprodol was above the lim




Psychopharmacology (Berl). 2004 Nov;176(3-4):426-34. Epub 2004 May 05.

Stimulant and relaxant drugs combined with stimulant and relaxant information: a study of active placebo.

Flaten MA, Simonsen T, Zahlsen K, Aamo T, Sager G, Olsen H.
Department of Psychology, University of Tromso, Breivika, 9037 Tromso, Norway.

RATIONALE: The active placebo hypothesis states that placebo effects are potentiated when an active drug is administered. OBJECTIVE: This hypothesis was tested in an experiment where information about the effect of a drug was combined with administration of an active drug or placebo. METHODS: Information that a drug acted as a relaxant, a stimulant, or as a placebo was crossed with oral administration of a relaxant drug (700 mg carisoprodol), a stimulant drug (400 mg caffeine) or placebo (lactose) in healthy volunteers ( n=94). Dependent variables were subjective and physiological measures of arousal, as well as serum carisoprodol and caffeine levels. Data were collected from 15 to 280 min after administration of drug or placebo. RESULTS: Caffeine increased alertness, systolic and diastolic blood pressure, startle blink reflexes, and skin conductance responses. Subjects were calmer after carisoprodol, and heart rate was increased. There was a positive correlation between increased arousal and carisoprodol levels when stimulant information had been provided. However, this was only seen when carisoprodol levels were very low. There was no evidence that caffeine modulated the placebo response. CONCLUSIONS: Active placebo responses were seen only transiently when carisoprodol levels were low, and only in the subjective arousal data. Caffeine did not support active placebo responses. The overall findings did not favour the active placebo hypothesis.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract soma carisoprodol &list_uids=15549277




Fundam Appl Toxicol. 1995 Jan;24(1):132-9.
Carisoprodol: reproductive assessment by continuous breeding in Swiss mice.

Grizzle TB, George JD, Fail PA, Heindel JJ.

Center for Life Sciences and Toxicology, Research Triangle Institute, Research Triangle Park, North Carolina 27709.

Carisoprodol (CARI), a commonly prescribed neuromuscular relaxant, was evaluated for reproductive toxicity in Swiss CD-1 mice using the Reproductive Assessment by Continuous Breeding (RACB) protocol. Male and female mice were given CARI in corn oil suspension by daily gavage at doses of 0, 300, 750, and 1200 mg/kg body wt/day. Clinical signs of general toxicity in F0 animals included sedation, primarily in the high-dose group during the first week of exposure, and reduced body weight in high-dose females. CARI administration for 14 weeks did not affect the ability of the F0 animals to produce litters. However, decreases in proportion of pups born alive (4%) and absolute (5%) and adjusted live pup weight (7%) were observed at 1200 mg/kg CARI when compared to controls. In a crossover mating trial to determine the affected sex, there were no significant differences in the measured reproductive parameters. CARI at the high dose increased the proportion of time spent in proestrus and estrus, but cycle length was unaffected. At F0 necropsy (Week 27 of treatment), all sperm parameters were normal. Right epididymis and liver weights, relative to body weight, were increased (12 and 23%, respectively) over the control group for high-dose males. A mating trial to determine the fertility and reproductive competence of the F1 generation showed no effect of CARI on indices of mating, pregnancy, or fertility, the proportion of F2 pups born alive, the sex ratio of live F2 pups, live F2 pup weight, or gestation length.(ABSTRACT TRUNCATED AT 250 WORDS)

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7713336&dopt=Abstract soma carisoprodol