PubMed · 15435662
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B LINDEMANN. 1950. [Simultaneous angiocardiotomography].. https://pubmed.ncbi.nlm.nih.gov/15435662/
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BACKGROUND: Administration of hydrocortisone and relatively high doses of dexamethasone increase blood pressure in volume- and pressor-resistant hypotensive preterm infants. However, little is known about the temporal relationship of dexamethasone administration and the improvement in blood pressure and the weaning of pressors/inotropes. Furthermore, there are no sufficient data available on whether a smaller dose of dexamethasone would also be effective in treating refractory hypotension. OBJECTIVE: To study the cardiovascular responses to low-dose dexamethasone in very low birth weight neonates with volume- and pressor-resistant hypotension. METHODS: Retrospective database review. Twenty-four preterm neonates (gestational age 26 (23-34) weeks; birth weight 801 (457-1,180) g; postnatal age 2 (1-24) days, medians (ranges)) who remained hypotensive despite volume administration and combined dopamine and dobutamine treatment at >or=30 microg/kg/min received dexamethasone 0.1 mg/kg followed by 0.05 mg/kg intravenously every 12 h for 5 additional doses if still on pressors >or=8 microg/kg/min. RESULTS: Two hours after the first dose of dexamethasone the mean blood pressure increased from 30 +/- 5 to 34 +/- 6 mm Hg (p < 0.001) and remained elevated at 4, 6, 12, and 24 h after treatment was started (p < 0.001). Six hours after the initial dose of dexamethasone the pressor/inotrope requirement decreased from 34 +/- 9 to 24 +/- 13 microg/kg/min (p = 0.001) and continued to decrease at 12 and 24 h (p < 0.001). Urine output also increased significantly during the first 6 h after dexamethasone (p < 0.001). CONCLUSIONS: Low-dose dexamethasone rapidly increases blood pressure and decreases pressor requirements in very low birth weight neonates with volume- and pressor-resistant hypotension.
The stimulant effects of cocaine and methamphetamine are mediated by changes in synaptic concentrations of brain monoamines; however, the drugs alter monoamine levels via different mechanisms. This study examined the subjective and cardiovascular responses produced by investigational administration of cocaine or methamphetamine, in order to examine the onset and patterns of subjective and cardiovascular responses. Subjects included 14 non-treatment seeking cocaine-dependent and 11 non-treatment seeking methamphetamine-dependent volunteers. As part of ongoing research studies, cocaine and methamphetamine subjects received cocaine (40 mg, IV) or methamphetamine (30 mg, IV), respectively. Subjective and cardiovascular responses were assessed for 30 min and 60 min, respectively. The data reveal significant within groups differences for all subjective effects and cardiovascular effects (p<0.05). Significant between group differences in subjective effects were observed for "Any Drug Effect" (p<.008 for group, and p<.029 for group x time), for "High" (p<.002 for group, and p<.0001 for group x time) and for "Stimulated" (p<.001 for group, and p<.006 for group x time). Significant between group differences in cardiovascular effects were observed for Systolic blood pressure (p<.0001 for group, and p<.002 for group x time), Diastolic blood pressure (p<.0001 for group, though p=NS for group x time), and for Heart Rate (p<.0001 for group, and p<.0001 for group x time). The only difference between the groups for placebo was for heart rate, where there was a significant group x time effect (p<.005). Taken together, the data reveal that the subjective effects of cocaine tended to peak and then decline more rapidly than those produced by methamphetamine. The subjective effects of methamphetamine tended to rise more slowly, and remain elevated longer. Cardiovascular effects of cocaine and methamphetamine had similar onset, but effects of cocaine tended to decline more rapidly. Overall, the results reveal differences in the onset, pattern, and duration of subjective and cardiovascular responses following cocaine or methamphetamine administration in stimulant addicted patients. We predict that these differences may impact drug use and relapse patterns, and may have implications in medications development for these addictive disorders.
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