Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0344232 (blurred vision)
 2,072 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tricyclic antidepressants are among the commonest causes of both non-fatal and fatal drug poisoning in the world. Their toxicity is due to effects on the brain, the heart, the respiratory system and the parasympathetic nervous system. Symptoms usually appear within 4 hours of an overdose and all but the most seriously poisoned patients recover within 24 hours. The most common clinical features are dry mouth, blurred vision, dilated pupils, sinus tachycardia, pyramidal neurological signs, and drowsiness. In severe poisoning, there may be coma, convulsions, respiratory depression, hypotension and a wide range of electrocardiographic (ECG) abnormalities. The most frequent findings on the ECG are prolongation of the PR and QT intervals; the tracing may resemble bundle branch block or supraventricular or ventricular tachycardias. Treatment of poisoning due to the tricyclic antidepressants is essentially supportive, there being insufficient evidence at present to recommend the use of methods to increase elimination of the drug from the body. Gastric aspiration and lavage should be performed if more than 750 mg of drug have been taken. There must be regular monitoring for hypoxia, acidosis and hypokalaemia and these complications should be corrected enthusiastically. Convulsions should be treated with diazepam or chlormethiazole. Muscular paralysis and artificial ventilation should be employed if anticonvulsants are ineffective. Hypotension should be treated firstly by fluid replacement and then with sympathomimetic agents (dopamine or dobutamine). Antiarrhythmic drugs should only be employed if there is evidence of circulatory failure which fails to respond to correction of hypotension. Sodium bicarbonate infusions should be given to cardiotoxic patients who are acidotic and are worth trying even if the patient is not acidotic. Although physostigmine salicylate will reverse most of the features of tricyclic antidepressant poisoning, its effects are short-lived in serious toxicity and it can produce dangerous side effects; physostigmine should therefore be reserved for those patients who have complications of coma or who have resistant cardiotoxicity or convulsions. Drug screening and quantitative determination of tricyclic antidepressant serum concentrations are useful in a minority of patients who have severe, unusual or prolonged symptoms.
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PMID:Poisoning due to tricyclic antidepressant overdosage. Clinical presentation and treatment. 353 21

Fifteen patients with ventricular premature complexes (VPCs) were included in this open study designed to assess the relative efficacy of bid (two times daily) and tid (three times daily) dosing regimens for cibenzoline as compared with qid (four times daily) administration. Patients started therapy with qid administration; this was followed in sequence by tid and bid administration at the maximum effective total daily dose determined during the qid administration. Of the nine patients evaluated for efficacy for suppression of VPCs, eight demonstrated a 75% or greater suppression of VPCs with cibenzoline administered qid (total daily dose of 130-325 mg). This effectiveness was maintained in four patients with a bid regimen and in three with a tid regimen. All four patients who had ventricular tachycardia (VT) had a decrease in the number of VT episodes while receiving cibenzoline (only one of these patients had satisfactory suppression of VPCs at the same dosage regimen). Twelve patients continued to receive extended therapy with cibenzoline for up to two years, as this was considered to be the optimum antiarrhythmic treatment for these patients. Two patients had to be removed from the study and two had the dosage lowered because of adverse reactions (dry mouth, blurred vision, dizziness, congestive heart failure) although in one instance, the congestive heart failure was subsequently considered to be unrelated to cibenzoline. One patient was able to complete the short-term phase of the trial, but was not given extended treatment because of persistent dry mouth. Two patients had treatment discontinued during the extended therapy phase because of adverse reactions (fever, nausea, vomiting, asthenia).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Evaluation of dosing interval and optimum dose of cibenzoline. 368 May 96

Hyoscine (scopolamine) is a competitive inhibitor of the muscarinic receptors of acetylcholine and it has been shown to be one of the most effective agents for preventing motion sickness. However, a relatively high incidence of side effects and a short duration of action has restricted the usefulness of this agent when administered orally or parenterally, and to counter this a novel transdermal preparation of hyoscine has been developed. Pharmacokinetic studies indicate that this new method for administering hyoscine controls the absorption process and the rate of drug entry into the systemic circulation over an extended period (72 hours), providing a means of delivery which is similar to a slow intravenous infusion. However, recent evidence suggests that the response to transdermal hyoscine treatment is variable and this may reflect pharmacokinetic differences between individuals. Controlled therapeutic trials have indicated that a single transdermal hyoscine patch is significantly superior to placebo and oral meclozine (meclizine) in preventing motion sickness. Trials comparing transdermal hyoscine with oral dimenhydrinate have failed to establish any significant differences in efficacy between the 2 drugs in small numbers of subjects, although there was always a more favourable trend towards the transdermal system. In patients with acute vertigo, transdermal hyoscine and oral meclozine were equally efficacious and both were significantly better than placebo in reducing the number of attacks of vertigo. Although transdermal hyoscine has been associated with a lower incidence of side effects than orally or parenterally administered hyoscine hydrobromide, adverse systemic effects have still been frequently reported. Most commonly cited have been dry mouth, drowsiness and impairment of ocular accommodation, including blurred vision and mydriasis (some ocular effects reported may be due to finger-to-eye contamination). Adverse central nervous system (CNS) effects, difficulty in urinating, rashes and erythema have been reported only occasionally. Thus, preliminary evidence suggests transdermal hyoscine may offer an effective and conveniently administered alternative for the prevention of motion-induced nausea and vomiting in certain situations. However, the duration of its clinical effectiveness, and its relative efficacy and tolerability compared with other agents needs to be confirmed in a few additional well-designed studies.
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PMID:Transdermal hyoscine (Scopolamine). A preliminary review of its pharmacodynamic properties and therapeutic efficacy. 388 52

Pirenzepine is a 'selective' antimuscarinic agent which, unlike classic anticholinergic agents, inhibits gastric acid secretion at lower doses than are required to affect gastrointestinal motility, salivary, central nervous system, cardiovascular, ocular and urinary functions. On a weight basis, pirenzepine has one-tenth to one-eighth the potency of atropine in inhibiting stimulated gastric acid secretion in humans. Extensive controlled trials utilising endoscopy in outpatients with duodenal ulcers indicate that patient response to pirenzepine is dose related. Doses of 100 to 150 mg/day are superior to placebo in promoting duodenal ulcer healing and in diminishing day and night pain and supplementary antacid consumption. At such doses, the efficacy of pirenzepine appears to be superior to that of gefarnate 300 mg/day and generally not significantly different from that of cimetidine 1 g/day in treating duodenal ulcers. A beneficial effect of pirenzepine in the prevention of duodenal ulcer recurrence was apparent in preliminary studies in small numbers of patients, but its efficacy in this regard needs further confirmation and the optimum dosage determined. Less extensive data on the treatment of benign gastric ulcers suggest that pirenzepine 100 to 150 mg/day is superior to placebo and gefarnate 300 mg/day and does not differ significantly from cimetidine 1 g/day promoting gastric ulcer healing. Pirenzepine is well tolerated by most patients, with a low incidence of typical antimuscarinic effects on the gastrointestinal tract, genitourinary system or heart being reported in clinical studies. However, dry mouth and blurred vision are the more common side effects with clinically effective doses. Thus, pirenzepine appears to have relatively selective antimuscarinic activity, although controlled studies comparing pirenzepine and conventional antimuscarinics in patients with peptic ulcer disease have not been reported.
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PMID:Pirenzepine. A review of its pharmacodynamic and pharmacokinetic properties and therapeutic efficacy in peptic ulcer disease and other allied diseases. 392 24

Tricyclic antidepressants (for example, amitriptyline) and other types of antidepressants (for example, amoxapine and maprotiline) are competitive antagonists of muscarinic acetylcholine receptors, the predominant class of acetylcholine receptors in the brain. Some evidence suggests that this muscarinic receptor blockade in brain alleviates depression. However, all tricyclic antidepressants appear to be equally effective in treating depression despite having differences in their antimuscarinic potencies while having similar ranges of therapeutic blood levels. It is more likely that the antimuscarinic potency of antidepressants is related mainly to the frequency with which they cause such symptoms as blurred vision, dry mouth, and urinary retention. Information on the antimuscarinic potency and other receptor-blocking potencies of antidepressant agents can be helpful in minimizing or avoiding certain side effects when these drugs are given to patients.
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PMID:Antimuscarinic and other receptor-blocking properties of antidepressants. 613 Jan 92

Twenty cancer patients who received chemotherapy were entered into a double-blind crossover design antiemetic study comparing 1 mg levonantradol, an investigational synthetic cannabinoid, to 10 mg prochlorperazine. Sixteen patients completed the crossover. For each antiemetic course, four doses of each study medication were given intramuscularly 2 hours before chemotherapy and then 2, 6, and 10 hours after chemotherapy administration. There were no statistical differences in patients' responses to levonantradol and prochlorperazine. The frequency of side effects was greater with levonantradol than with prochlorperazine. The most common side effect of levonantradol were somnolence, dry mouth, dizziness, tachycardia, postural hypotension, and blurred vision, while those for prochlorperazine were somnolence, dry mouth, and tachycardia.
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PMID:Double-blind multiple-dose crossover study of the antiemetic effect of intramuscular levonantradol compared to prochlorperazine. 637 43

In a 6-week double-blind parallel treatment study, dothiepin and amitriptyline were compared to placebo in the treatment of 33 depressed outpatients. Dothiepin and amitriptyline were equally effective in alleviating the symptoms of depressive illness, and both were significantly superior to placebo. The overall incidence of side effects and the frequency and severity of blurred vision, dry mouth, and drowsiness were significantly less with dothiepin than with amitriptyline. Dothiepin also produced fewer CNS and cardiovascular effects. There were no clinically important changes in laboratory parameters. Dothiepin thus was found to be an effective antidepressant drug associated with fewer side effects than amitriptyline in the treatment of depressed outpatients.
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PMID:A double-blind study of the efficacy and safety of dothiepin hydrochloride in the treatment of major depressive disorder. 638 93

The new selective serotonin (5-HT)-uptake inhibitor femoxetine was compared with amitriptyline in a double-blind clinical trial comprising 77 depressed patients. The depressive symptoms were evaluated with the Hamilton rating scale, and a global clinical evaluation. Both drugs showed an antidepressive effect and no significant differences were found. Femoxetine induced a significantly lower frequency of dry mouth and blurred vision; this difference is presumably due to the weak anticholinergic effect of this substance. A small but significant weight loss was observed in the femoxetine group but not in the amitriptyline group.
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PMID:A controlled double-blind study of femoxetine and amitriptyline in patients with endogenous depression. 675 83

The pharmacology, pharmacokinetics, clinical trials, side effects, and dosage of amoxapine are reviewed. Amoxapine is a tricyclic dibenzoxazepine antidepressant that is chemically similar to the antipsychotic agent loxapine. In animal tests, amoxapine and its metabolites block reuptake of the neurotransmitter norepinephrine, with little effect on serotonin. It is rapidly and virtually completely absorbed when administered orally; peak serum concentrations occur one to two hours after ingestion. Amoxapine is widely distributed throughout body tissues and is 90% bound to serum proteins. Aromatic hydroxylation in the liver produces two major metabolites, which are excreted in the urine primarily but also in the feces. Amoxapine's elimination half-life is eight hours; one of the metabolites has a long half-life (30 hours). In clinical trials, amoxapine has been compared with amitriptyline and imipramine in several types of depressed patients. In some studies, amoxapine's therapeutic effects were measurable earlier (at one or two weeks after initiation of therapy) than those of the amitriptyline or imipramine, but generally only a portion of the depression-rating scales yielded statistically significant differences. Side effects noted during amoxapine therapy include hypotension (42%), drowsiness (14%), xerostomia (14%), constipation (12%), blurred vision (7%), fatigue (5%), and vertigo (5%). Amoxapine is approved by FDA for use in patients with neurotic or reactive depressive disorders, endogenous or psychotic depression, and depression accompanied by anxiety or agitation. The usual adult dosage is 200-300 mg daily, either in divided doses or a single bedtime dose. Amoxapine is a safe and effective antidepressant with no striking advantages over other available agents.
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PMID:Evaluation of amoxapine. 676 65

Two possibilities of an inhibition of gastric acid secretion are compared in regard to effectiveness and side effects. Combined i.v. bolus injection of 0.3 mg/kg cimetidine caused almost complete inhibition of peptone-stimulated acid secretion in normal volunteers and duodenal ulcer patients-radomized and double blind investigated-to the same extent as high dose secretin (3 CU/kg/h i.v. infusion) in normal volunteers. Postprandial gastrin was unchanged by combined drug application, but was suppressed by secretin. Temporary blurred vision, dry mouth, and signifiant increase of serum prolactin were side effects of the drug combination, whereas secretin caused dose-dependent diarrhoea, increaded diuresis and elecvation of serum lipase, trypsin, and sodium. Inhibition of acid secretion by combination of the antimuscarinic drug pirenzepine with the H2-receptor blocking substances cimetidine was almost complete, i.e. more effective than the combination of classic anticholinergics with H2-blockers tested so far. Inhibition of acid secretion by secretin was dose-dependent; the dosage clinically applied so far (10 CU/kg s.c. and 0.5 CU/kg/h i.v.) had the smallest effect. In spite of first favourable results with secretin in bleeding mucosal lesions, the observed side effects cast doubt on its broad clinical applicability. A controlled clinical trial of the combination of cimetidine plus pirenzepine as prophylaxis of bleeding from mucosal lesions in risk patients seems to be indicated.
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PMID:[Effectiveness of cimetidine, pirenzepine and synthetic secretin on stimulated gastric acid secretion]. 689 78


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