Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0012833 (dizziness)
 9,689 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report four cases of carbamazepine toxicity in children associated with the concurrent administration of erythromycin. They all developed clinical toxicity (ataxia, dizziness, nausea, and vomiting) when erythromycin administration was begun; symptoms disappeared after erythromycin was discontinued. Serum carbamazepine levels were measured before, during, and, in most cases, after the toxic episodes. In all cases, there was a sharp increase in carbamazepine concentration after erythromycin therapy was begun and a rapid fall once erythromycin was discontinued. Our data support the previous suggestion that erythromycin interferes with the liver microsomal metabolism of carbamazepine with a subsequent increase in blood levels of the drug.
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PMID:Carbamazepine--erythromycin interaction leading to carbamazepine toxicity in four epileptic children. 665 14

Ingestion of a moderate dose of ethanol (0.8 g/kg) by volunteers prior to 4-h inhalation exposure to m-xylene (6.0 or 11.5 mmol/m3) caused marked alterations in xylene kinetics. After ethanol intake the blood xylene level rose about 1.5-2.0-fold and urinary methylhippuric acid excretion declined by about 50% suggesting that ethanol decreased the metabolic clearance of xylene by about one half during xylene inhalation. This effect was noticeable up until a few hours after completed xylene exposure. Urinary excretion of 2,4-xylenol, the minor m-xylene metabolite, was generally not decreased by ethanol and sometimes the reverse seemed to be the case. The disturbance of xylene kinetics can be hypothesized to be caused mainly by ethanol-mediated inhibition of microsomal metabolism. When four volunteers who ingested ethanol prior to m-xylene inhalation at the higher concentration were monitored for blood acetaldehyde, transiently raised levels were found without notable effects on ethanol elimination. This observation may explain why some individuals experienced dizziness and nausea during the combined ethanol-xylene exposure.
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PMID:Metabolic interaction between m-xylene and ethanol. 709 64

Sildenafil citrate, an oral therapy for erectile dysfunction, is a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5), the predominant isozyme metabolizing cGMP in the corpus cavernosum. Chemically, it is a compound of the pyrazolo-pyrimidinyl-methylpiperazine class. Sildenafil has no direct relaxant effect on human corpus cavernosum but enhances the relaxant effect of nitric oxide (NO) on the corpus cavernosum by inhibiting PDE5, which is responsible for degradation of cGMP in this tissue. When sexual stimulation causes local release of NO, inhibition of PDE5 by sildenafil increases concentrations of cGMP in the corpus cavernosum, causing smooth muscle relaxation and blood flow into the penis, resulting in an erection. Sildenafil at recommended doses has no effect in the absence of sexual stimulation. The drug is rapidly absorbed after oral administration, with absolute bioavailability of 40%. Its pharmacokinetics are dose proportional over the recommended dosage range. Maximum plasma concentrations are reached within 30 to 120 minutes after oral dosing in the fasting state. Sildenafil is cleared predominantly by the hepatic microsomal isoenzymes CYP3A4 (major route) and CYP2C9 (minor route). Clinical studies assessed the effect of sildenafil on the ability of men with erectile dysfunction to engage in sexual activity and, specifically, to achieve and maintain an erection sufficient for satisfactory sexual intercourse. Sildenafil was evaluated at doses of 25, 50, and 100 mg in randomized, double-masked, placebo-controlled clinical trials of up to 6 months' duration. The drug was administered to hundreds of patients aged 19 to 87 years having erectile dysfunction of various etiologies for a mean duration of 5 years. Sildenafil was associated with statistically significant improvement in erectile function compared with placebo. Adverse effects reported at a rate of >2% were headache, flushing, dyspepsia, nasal congestion, urinary tract infection, abnormal vision, diarrhea, dizziness, and rash. No cases of priapism were reported. The use of sildenafil is contraindicated in men who are taking organic nitrates, because of the potential for a precipitous decrease in blood pressure. Postmarketing reports and surveillance have revealed at least 39 deaths with sildenafil use in men having a history of heart disease, men taking nitrate medications, and men in poor physical health due to lack of exercise. Many of the men who experienced serious adverse effects or death had a variety of concomitant diseases and were taking multiple medications.
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PMID:Safety and efficacy of sildenafil citrate in the treatment of male erectile dysfunction. 991 1

The metabolic fate of most antihistamines is not clearly established. The drugs usually appear to be extensively metabolized,mainly in the liver. Some second generation antihistamines are metabolized principally by the cytochrome P-450 microsomal enzyme system, mainly by the isoenzyme 3A4 (CYP3A4), although other isoenzyme,including CYP1A2 and CYP2D6, also may be involved. However,other second generation antihistamines appear to be only minimally metabolized in the liver. Serious cardiac effects (prolongation of the QT interval, arrhythmias, torsades de pointes, ventricular fibrillation, arrest, hypotension, palpitations, syncope, dizziness, and/or death) have been reported rarely in patients receiving terfenadine or astemizole. Cardiotoxic effects ussually were associated with higher than recommended dosages and/or increased plasma concentrations of the drugs and their active metabolites. No clinically important adverse effects or changes in the QT intervals were reported after concomitant administration of ketoconazole with fexofenadine. Patients receiving an azole, antifungal, a macrolide, quinine or grapefruit juice also appear to be at substantial risk of such toxicity, probably secondary to interference with metabolism of the antihistamine. Second-generation H1 receptor antagonist have been studied extensively in the treatment of asthma. Many of these drugs have been reported to inhibit eosinophil and basophil chemotaxis and therefore might have an effect on the inflammatory reactions that characterise this disease. Safe use of antihistamines during pregnancy has not been established; therefore, the drugs should not be used in women who are or may become pregnant unless the potential benefits justify the possible risks to the fetus. Antihistamines should not be administered to premature or full-term neonates. Young children may be more susceptible than adults to the toxic effects of antihistamines.
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PMID:[Projection of new antihistamines]. 1086 85

Thyrotoxicosis has a variety of presentations. Vomiting as a main presenting symptom of thyrotoxicosis is uncommon. We report a 40-year-old male with thyrotoxicosis who presented with sustained vomiting as the main symptom. He also had weight loss, about 10 kg over this 20-day period, and dizziness, particularly in the upright position. Esophagogastroduodenoscopy and abdominal ultrasonography were negative. Laboratory data were unremarkable except serum T4 of 21.2 microg/dl, T3 of 574 ng/dl and TSH < 0.03 microIU/ml. The patient's serum microsomal antibody was positive at a titer of 1:409,600, but serum thyroglogulin antibody was negative at a titer of less than 1:100. The symptoms improved after adminstroction of propylthyrouracil and propranol. A total of 31 such cases have been reported in English literature. The mean age of the patients was 46 +/- 14 year with a range of 19 to 68 years. Only 4 patients, including ours, were male. Weight loss was found in about half of them and might be an important clue. Thyrotoxicosis should be considered in differential diagnosis of unexplained vomiting.
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PMID:Severely sustained vomiting as the main symptom in a man with thyrotoxicosis. 1290 76

Yahom Tultavai is a Thai traditional medicine that has been widely used for the treatment of nausea, vomiting, dizziness and weakness in aged-people, especially. Its formula contains several medicinal plants, and one of them is Kaempferia galanga L., which has ethyl-p-methoxycinnamate (EPMC) as its major compound. Recently, several herbs and traditional medicines have been reported to demonstrate herbal-drug interaction with conventional medicines. This study aims to investigate the effect of Yahom Tultavai extracts on hepatic cytochrome P450 enzymes and pentobarbital-induced sleeping in mice. Three extracts of Yahom Tultavai, using dichloromethane, methanol and distilled water as solvents were orally administered for 28 days prior to determine CYP1A1, CYP1A2, CYP2B, CYP2E1 and CYP3A4 activities. All three extracts significantly inhibited CYP1A1, CYP1A2 and CYP 2E1 activities, but only dichloromethane extract enhanced CYP2B activity. In addition, all three extracts had no effect on CYP3A4 activity. As an indicator for metabolic drug interaction, pentobarbital-induced sleeping time was decreased in connection with the induction of CYP2B activity between 7 and 28 days of dichloromethane extract and EPMC-treated animals when compared to control. In conclusion, Yahom Tultavai extracts affected hepatic microsomal CYP enzyme activities and reduced pentobarbital-induced sleeping time in mice. The results suggest that Yahom Tultavai may potentially cause herbal and conventional drug interaction, which can affect the clinical implication of drug action. Therefore, the co-administration of Yahom Tultavai with certain drugs should be carefully considered.
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PMID:Moduratory effect of Thai traditional medicine (Yahom Tultavai) on hepatic cytochrome P450 enzymes and pentobarbital-induced sleeping in mice. 2414 13