International journal of clinical pharmacology, therapy, and toxicology
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Int J Clin Pharmacol Ther Toxicol · Apr 1989
Phenytoin Michaelis-Menten pharmacokinetics in Saudi patients.
The Michaelis-Menten pharmacokinetic parameters Vmax and Km were calculated for 17 epileptic Saudi patients receiving phenytoin. Their ages ranged from 2.5 to 47 years (mean 21 years) and their weight ranged from 9.5 to 80 kg (mean 53 kg). Eight were females and 9 were males. ⋯ There is a significant increase in Vmax with weight (r = 0.816, p less than 0.01). A plot of Km vs age and weight showed a poor correlation (r = 0.302, r = 0.218, respectively) and a large amount of variability. Based on this data, the daily phenytoin doses for children and adults are 7.21 mg.kg-1 and 4.83 mg.kg-1, respectively, in order to achieve and maintain a steady-state phenytoin concentration of 15 mg.l-1.
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Caffeine is ubiquitous in our environment and is the most widely used psychoactive drug in the world. Caffeine works on every system in the body mediated by the central nervous system. Caffeine has the opposite effect of adenosine and is the antagonist at the inhibitory A1-receptor. ⋯ Caffeine is used for the treatment of apnea of prematurity and as an additive in several analgesics and migraine remedies, and as a panacea for hyperkinetic children. Although much work has been done to establish the relationship between caffeine and cancer and mutagenicity, none of these have established a cause-effect relationship. The consumption of caffeine products in moderation appears to be safe at this point.
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Int J Clin Pharmacol Ther Toxicol · Jul 1988
Randomized Controlled Trial Clinical TrialAttenuation of pulse rate and blood pressure response to laryngoscopy and tracheal intubation by clonidine.
Forty healthy patients (ASA class 1) of both sexes, aged between 20 and 45 years, undergoing routine surgical procedures were included in this double-blind randomized study. They were divided into two groups of 20 each. ⋯ Control patients showed a significant increase in heart rate and blood pressure; they were significantly lower in the clonidine treated group immediately after intubation (p less than 0.001). The data suggest that the rise in heart rate and blood pressure associated with laryngoscopy and intubation during a routine induction sequence can be attenuated by the use of oral clonidine.
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Int J Clin Pharmacol Ther Toxicol · Jul 1988
Case ReportsSuccessful treatment of hyperkalemic quadriplegia associated with spironolactone.
Hyperkalemic flaccid quadriplegia and cardiotoxic disturbances developed during antihypertensive therapy with spironolactone in a 76-year-old woman with chronic renal insufficiency. Hyperkalemia was successfully overcome and followed by the disappearance of all cardiac and muscular disorders. ⋯ Our studies suggested that no primary insufficiency of the renin-aldosterone and glucocorticoid systems had been responsible for the hyperkalemia, therefore, it could be contributed entirely to the effect of spironolactone abolishing the K+ secreting capacity of the already decreased renal mass. Further studies revealed that blocking action of the drug on H+ secretion ("renal tubular acidosis") may also have had a role-in addition to the K+ retention-in the development of the spironolactone-induced hyperkalemia.
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The effects and safety of using sublingually nifedipine 10-20 mg as acute antihypertensive treatment were evaluated in 108 patients with hypertensive emergencies or urgency without intensive care monitoring. Before treatment, mean systolic blood pressure was 220 +/- 28 mmHg, mean diastolic blood pressure was 125 +/- 15 mmHg and mean arterial pressure was 155 +/- 14 mmHg. Administration of 10 mg of sublingual nifedipine reduced the blood pressure within 10 min and produced a peak effect level between 30 to 40 min. ⋯ Heart rate increased from 74 +/- 10 to 84 +/- 10 beats per min. The response to nifedipine correlated with the blood pressure value prior to treatment, but did not correlate with age or the type of hypertensive emergency. These results indicate that nifedipine administered sublingually is a simple, effective, and safe agent for treating hypertensive emergencies, especially for the patients in whom intensive care monitoring cannot be guaranteed.