Biomedical subjects

C A Naranjo

Publications and source records attributed to C A Naranjo.

At least 91 records · Page 5Linked to original sources

PubMed1985

Is there acute tolerance to alcohol at steady state?

Although acute tolerance to the psychomotor impairment caused by alcohol has been documented in single-dose studies, the pharmacodynamic effects of continued alcohol administration in humans have not been well studied. Six nonalcoholic men received alcohol to achieve and maintain breath alcohol levels of 80-100 mg/dl for 6 hr. The men suffered an initial impairment in word recall but improved over the next 6 hr. Measures of standing steadiness and manual tracking did not show evidence of the development of tolerance. This lack of tolerance was reflected in subjects' self-assessments of sedation and intoxication.

Adult↗

PubMed1984

Diazepam tapering in detoxification for high-dose benzodiazepine abuse.

The clinical characteristics and management of patients who abuse high doses of benzodiazepines are not well described. In a prospective open study, 23 subjects who abused high doses of benzodiazepines were admitted for detoxification. Urine or blood test results confirmed benzodiazepine use in all but one subject and multiple drug use in eight (35%). Median benzodiazepine dose was 150 mg (range 40 to 500 mg) of diazepam equivalent. Initial plasma concentrations (diazepam: median = 1245 ng/ml; desmethyldiazepam: median = 2961 ng/ml) were 400% to 800% higher than usual therapeutic concentrations. For detoxification, subjects were given a loading dose of diazepam equal to approximately 40% their reported daily consumption. This was followed with daily tapering of diazepam by 10%. This regimen resulted in a slow and gradual decline in drug concentrations. Withdrawal symptoms were assessed daily. Sixteen subjects completed detoxification in the hospital without complications. One subject became paranoid and confused on day 7 of withdrawal. This was attributed to a too-low initial loading dose and too-rapid tapering, which resulted in rapid drug elimination. Gradual reduction of diazepam dose appears to be an effective and safe approach for detoxifying abusers of high doses of benzodiazepines.

Adult↗

PubMed1984

Acute kinetic and dynamic interactions of zimelidine with ethanol.

The acute interaction of zimelidine (Z) with ethanol (E) was examined in six healthy men aged 20 to 37 yr who randomly received each of four treatments 1 wk apart: Z, 200 mg by mouth, preceded by 1 hr and followed for 7 hr of oral E in juice dosed to maintain blood alcohol concentrations between 800 and 1000 mg/l; placebo Z and E; Z and juice; and placebo Z and juice. E decreased the rate of biotransformation of Z to norzimelidine (NZ) by 46%, but the AUCs of Z, NZ, and their total concentration over 8 hr were not altered by E. Acetaldehyde concentrations did not change and no aversive alcohol-sensitizing reaction was detected. E-induced impairments in memory, body sway, and a manual tracking task were further enhanced by Z, as was the E-induced decrease in friendliness. Data suggest Z and E interact kinetically and dynamically and suggest a mechanism whereby Z may decrease E intake in man.

Administration, Oral↗

PubMed1984

Zimelidine-induced variations in alcohol intake by nondepressed heavy drinkers.

The effect of zimelidine, a specific serotonin-reuptake inhibitor, on alcohol intake was tested in 13 healthy male, nondepressed heavy drinkers who were randomly allocated to receive zimelidine or placebo in a double-blind, crossover experiment. There were five 2-wk experimental periods (baseline, placebo 1 and 2, and zimelidine 1 and 2). Treatment was discontinued in three subjects due to a suspected adverse reaction and three other subjects dropped out. Thus, 13 subjects participated in at least two experimental drug periods and only 10 participated in all the periods. In the 13 subjects zimelidine increased the days of abstinence and decreased the daily number of drinks consumed, whereas in the 10 subjects only the number of days of abstinence increased. Subjects did not report aversive alcohol-sensitizing reactions. Spielberger state-anxiety test scores and depression scores (Montgomery/Asberg and Hamilton) were low at the beginning and throughout the study. Our data suggest that zimelidine modifies alcohol intake by a different mechanism than previously tested drugs, possibly by modulating the central neural mechanism that controls drinking of alcohol.

Adult↗

PubMed1984

The role of drugs in the treatment of alcoholism.

Many drugs are used in alcoholism treatment with the aim of reducing alcohol consumption and correcting alcohol-related psychosocial problems that lead to excessive drinking or result from it. Alcohol-sensitising drugs are used to reduce alcohol consumption with the expectation that improvement in other problem areas will follow. Drugs that share sedative-hypnotic actions with and cross-dependence to alcohol are often used during acute alcohol withdrawal reactions for symptomatic relief, to prevent major withdrawal symptoms, and to prevent and treat seizures. Alcohol abuse may be a form of self-medication, and treatment of an underlying psychiatric disorder, such as depression (with antidepressants), anxiety (with anxiolytics) or psychosis (with antipsychotics), is expected to reduce alcohol consumption. Pretreatment medical and psychiatric assessment of the patient is necessary to ensure that the drug therapy is appropriate to the patient's therapeutic goals and medical/psychological status. Use of the drug must be systematic and carefully monitored; the duration of treatment is determined individually for each patient on the basis of the response to the treatment as well by the development of adverse clinical effects. Ideally, the drug therapy allows the patient to establish resources necessary for continued abstinence after the drug treatment is stopped.

Acetaldehyde↗

PubMed1983

Nonpharmacologic intervention in acute alcohol withdrawal.

The importance of nonpharmacologic and pharmacologic interventions in the treatment of alcohol withdrawal is not known. A randomized, double-blind, placebo-controlled trial was conducted with 41 patients in alcohol withdrawal in an emergency department. The patients received either supportive care (10 min of standardized assessments, reassurance, reality orientation, and nursing care an hour) with three doses of sublingual lorazepam 2 mg every 2 hr (21 patients, drug group) or supportive care with three doses of sublingual placebo every 2 hr (20 patients, no-drug group). Immediately before each drug dose, the clinical course of alcohol withdrawal was assessed hourly by the Clinical Institute Withdrawal Assessment for Alcohol (CIWA-A). Interraters reliability in using CIWA-A was high. After each assessment, supportive care was given for 10 min before each dose. After completion of a 7-hr initial phase, patients were discharged and reassessed daily for 5 days. Thirty-seven patients (90.2%) improved in the initial phase. Treatment failures (CIWA-A greater than 10) were more common in the patients treated without drug (3/20, 15%) than in those treated with drug (1/21, 4.8%). Overall variations in intergroup CIWA-A scores during the initial phase were not significant. The rate of improvement of CIWA-A scores over the first 2 hr after drug was slightly faster in patients receiving lorazepam than in the control group. CIWA-A scores were the same during follow-up. These results indicate that most outpatients in mild to moderate alcohol withdrawal without medical complications improve without drug therapy in the emergency department setting.

Adult↗

PubMed1983

Diazepam loading: simplified treatment of alcohol withdrawal.

Alcohol withdrawal therapy can be simplified with a loading dose of diazepam, taking advantage of the kinetic tapering afforded by the drug's long t 1/2s and its metabolites, and of the effectiveness of nonpharmacologic maneuvers. In a double-blind trial, 50 inpatients in moderate to severe alcohol withdrawal received 20 mg oral diazepam and supportive care (n = 25) or placebo and supportive care (n = 25) every 2 hr until they were asymptomatic. Fifty-six percent of patients responded to placebo within 5 +/- 2.9 hr (mean +/- SD), whereas 72% responded to initial diazepam within 6.3 +/- 3.9 hr. Patients treated with diazepam had more rapid and greater improvement than those treated with placebo. Patients who did not respond to six doses of diazepam received further (unblinded) diazepam, 20 mg, every 1 to 2 hr. All patients who did not initially respond (n = 18) improved after more diazepam. Thus all patients who received diazepam (n = 36), during the experimental phase or subsequently, were effectively treated. There were no adverse effects. The median number of 20-mg diazepam doses to treat alcohol withdrawal were three, given over a period of 7.6 hr (range = 1 to 12 and 0.33 to 45 hr). Complications occurred only in those who received placebo during the experimental phase, indicating that delay in therapy may be responsible for the appearance of complications in alcohol withdrawal.

Adult↗

PubMed1983

An intensive drug monitoring study suggesting possible clinical irrelevance of impaired drug disposition in liver disease.

1 Liver disease can alter the disposition and clinical effects of drugs. However, even though altered drug disposition occurs, there is no clinical evidence relating it to an increased susceptibility to adverse drug reactions (ADRs). 2 An intensive prospective drug monitoring study of 2,582 hospitalized patients was conducted. The adverse drug reactions probability scale (APS) was used to assess ADRs. Only non-mild, definite or probable ADRs (APS greater than or equal to 5) were included. Severity of liver dysfunction was assessed by a composite clinical and laboratory index (CCLI). 3 The frequency of ADRs was higher in 402 patients with cirrhosis (27.4%) than in 661 with renal dysfunction (22.8%) and in 249 with other parenchymatous liver diseases (13.7%) or in 1,270 patients with neither liver diseases nor renal dysfunction (10.9%) (chi 2 3 = 85.53, P less than 0.001). The frequency of ADRs in cirrhotics was highly correlated with the severity of the liver dysfunction measured by CCLI (r = 0.82, P less than 0.001). 4 Drugs predominantly eliminated by liver metabolism were not among those most commonly inducing ADRs or those causing severe reactions in cirrhotics. Thus, frusemide caused the most common and the most severe ADRs, whereas reactions induced by sedatives were uncommon. Drug-induced hepatic encephalopathy was more common in cirrhotics receiving diuretics (13.3%) than in those receiving sedatives (1.8%) (chi 2 y.c. = 5.29, P less than 0.025). Patients with alcoholic liver disease had more drug-induced hepatic encephalopathy (7.7%) than those with non-alcoholic liver disease (1.2%) (chi 2 y.c. = 11.86, P less than 0.001). 5 These results indicate that susceptibility to ADRs is increased only in severe cirrhosis and that the most common and severe ADRs seem more likely related to enhanced pharmacodynamic action than to impaired drug disposition.

Brain Diseases↗

PubMed1983

Variations in drug free fraction during alcohol withdrawal.

1 Free fractions of diazepam, propranolol and warfarin were determined in 15 male chronic alcoholics in alcohol withdrawal. 2 On admission the mean free fraction of diazepam was 25% above and propranolol 44% below the limits of normal range, while the mean warfarin free fraction was in high normal range. One week later mean free fraction of diazepam declined by 20% while propranolol and warfarin increased by 24% and 19% respectively (P less than 0.05). 3 Propranolol free fraction and alpha 1-AGP concentrations were highly correlated (linear r = -0.83, P less than 0.001). In contrast the sources of variation in diazepam and warfarin free fraction were more complex and less certain. 4 Statistically significant changes of drug free fractions in serum of chronic alcoholics were observed during alcohol withdrawal. The extent and direction of these changes differed for various classes of drugs and their potential causes appear to be quite different. 5 Clinically important changes in drug effect may be present acutely, within the dosing interval, as a result of altered drug binding. These are more likely when the clinical response is closely related to drug concentration and will occur within the dosing interval due to larger fluctuations in free drug concentration, even though the average free drug concentration will remain unchanged. 6 Total drug level changes will be observed during alcohol withdrawal even in absence of detectable changes of drug metabolism.

Adult↗

PubMed1982

Difficulties in assessing adverse drug reactions in clinical trials.

1. The discovery of an adverse drug reaction (ADR) depends on: the relative frequencies of the drug-related and non-drug events; the mechanism of drug-induced toxicity; the number of patients exposed to the drug; and the methods used for detecting toxicity. Clinical trials are usually short-term studies conducted in a few hundred patients before marketing a drug. Therefore only the most common acute, dose-related ADRs are usually detected in the pre-marketing phase. 2. The detection and assessment of ADRs in clinical trials is still inadequate. Unstructured (open-ended questionnaires) and structured procedures (checklists) are the methods most commonly used. Since both methods have limitations, the discovery of ADRs in pre-marketing trials (phases I to III) should also rely on the complementary information provided by other methods: physiological and physical examinations, and pertinent laboratory tests. A more definite assessment of individual cases of ADRs should include the use of the adverse drug reaction probability scale (APS) or similar procedures. 3. Because the knowledge on the clinical toxicity of a drug will always be incomplete at the time of marketing, further investigation of the frequency and determinants of ADRs must be pursued in the post-marketing phase.

Arousal↗

PubMed1982

Nonfatty acid-modulated variations in drug binding due to heparin.

Changes in free fatty acids (FFAs) do not always correlate with variations in drug binding. To dissociate heparin effects on FFAs and drug binding, six healthy fasting subjects received 50 units (USP) IV heparin (Harris L932) with and without protamine (3.2 mg IV). Protamine completely suppressed heparin-induced rises in FFAs and warfarin free fraction (W alpha), but diazepam free fraction (D alpha) increased (P less than 0.005). In vitro, increasing concentrations of heparin added to serum increased D alpha (P less than 0.0005) and W alpha (P less than 0.005) without changing FFAs. In eight subjects given 50 units IV heparin (Harris L014), FFAs (P less than 0.001) and propranolol free fraction (P alpha) rose (P less than 0.01), but variations in FFAs and P alpha did not correlate (r = 0.18). When two different heparin lots (Harris L014 and Organon LA39) were tested in vivo. Harris L014 heparin increased FFAs (P less than 0.005) and P alpha (P less than 0.0005), but variations in FFAs and P alpha correlated poorly (r = 0.43, P less than 0.05). In contrast, the Organon LA39 heparin did not change FFAs, but did increase P alpha (P less than 0.0005); variations in FFAs and P alpha did not correlate (r = 0.22). These results indicate that heparin-induced variations in drug binding are not exclusively related to changes in FFAs.

Adult↗

PubMed1982

Comparison of two recently published algorithms for assessing the probability of adverse drug reactions.

1 A simple valid and reliable method for estimating the probability of adverse drug reactions (adverse drug reactions probability scale, APS) has been recently described (Naranjo et al., 1981a). 2 The results using APS were compared to those obtained with another more detailed algorithm (adverse reactions scoring system, ASS) described by Kramer et al. (1979). 3 Sixty-three randomly selected adverse drug reactions (ADRs) were rated by two observers, using APS and ASS one year apart. The cases were ordered in a random sequence. Between-raters reliability using APS (R(est) = 0.96 and ASS (R(est) = 0.86), was very high. 4 ADR scores obtained with both methods were highly correlated (r = 0.82, P less than 0.001). However, time spent using ASS was significantly longer (paired t-test, t = 1.70, P less than 0.05). 5 These results suggest that while ASS is somewhat more complex than APS both are equally reliable and will give very similar conclusions regarding the probability of ADRs. Such algorithms must be used if the clinical assessment of ADRs is to become acceptably reliable.

Drug-Related Side Effects and Adverse Reactions↗

PubMed1982