Pseudoephedrine toxicity

Although pseudoephedrine toxicity was a possible diagnosis, the authors concluded that serotonin syndrome was more likely, from an interaction of pseudoephedrine with fluoxetine. Patients should be warned about the hazards of taking selective serotonin re-uptake blockers and then self-medicating with ephedrine or pseudoephedrine. 

Lyon CC, Turney 1H. Pseudoephedrine toxicity in renal failure. Br J Clin Pract 1996 50(7) 396—397. 

Weddle RL. Possible trazodone-pseudoephedrine toxicity a case repot. Neurcbehav T[Pg.1229]

Adrenaline hypertension Anticoagulants, oral skin necrosis Antituberculosis drugs hepatotoxicity Pseudoephedrine toxic epidermal necrolysis SSRIs suicidal behavior Statins acute pancreatitis Ximelagatran liver damage... 

SYMPATHOMIMETICS ANTACIDS-SODIUM BICARBONATE Possibly t ephedrine/ pseudoephedrine levels Alkalinising urine 1 excretion of these sympathomimetics Watch for early features of toxicity... 

A form of toxic shock syndrome on more than one occasion occurred in one patient who used pseudoephedrine (SEDA-18,158). 

Hypertension and tachycardia are the primary toxic manifestations of pseudoephedrine overdose. An amount of more than three or four times the maximum daily dosage for adults or children may produce symptoms of jS-adrenergic stimulation. In severe poisonings, cardiac dysrhythmias and cerebral hemorrhage due to hypertensive crisis may occur. Anxiety, muscle tremor, and seizures may result from CNS stimulation. Hallucinations, drowsiness, and/or irritability are more common symptoms exhibited by children. Hypokalemia and hyperglycemia may be noted. Acute renal failure and rhabdomyolysis have occurred in rare instances with large overdoses. 

Pseudoephedrine concentrations, but not measurements for ephedrine or any of the other enantiomers, have been published by the National Association of Medical Examiners in their Annual Registry report. In 15 children diagnosed with sudden infant death syndrome, the mean blood pseudoephedrine concentration was 3.55 mg/L, the median 2.3 mg/L, with a range of 0.07-13.0 mg/L (SD = 3.36 mg/L). The authors of the study take pains to point out that The data do not allow definitive statements about the toxicity of pseudoephedrine at a given concentration (129). 

Antidepressants selective serotonin reuptake inhibitors, tricyclic antidepressants Antihypertensives felodipine Antibiotics quinolones, isoniazid Bronchodilators albuterol, theophylline Corticosteroids prednisone Dopa agonists levodopa Herbals ma huang, ginseng, ephedra Nonsteroidal anti-inflammatory drugs ibuprofen Stimulants amphetamines, methylphenidate, caffeine, cocaine Sympathomimetics pseudoephedrine Thyroid hormones levothyroxine Toxicity anticholinergics, antihistamines, digoxin Withdrawal alcohol, sedatives... 

Elimination of ephedrine, pseudoephedrine, and phenylpropanolamine is predominantly renal. Urinary excretion of all three enantiomers is pH dependent. Excretion patterns may be much more rapid in children, and a greater dosage may be required to achieve therapeutic effects. Patients with renal impairment are at special risk for toxicity. 

B. Pseudoephedrine Is less toxic, with symptoms occurring after four- to fivefold the usual therapeutic dose. 

In 8 healthy subjects a single 150-mg oral dose of phenylpropanolamine decreased the clearance of theophylline (given as a single 4-mg/kg intravenous dose of aminophylline 1 hour after the phenylpropanolamine) by 50%. Such a large reduction in clearance would be expeeted to result in some increase in serum theophylline levels, but so far no studies of this potentially clinically important interaction seem to have been earried out in patients. Be alert for evidence of toxicity if both drugs are used. More study is needed. See also Pseudoephedrine and related drugs + Caffeine , p.1276. 

A single report describes toxicity in a woman treated with trazodone when she took pseudoephedrine. 

Alkalinisation of the urine (e.g. by sodium bicarbonate) causes retention of ephedrine and pseudoephedrine by the kidneys, leading to the possible development of toxicity (tremors, anxiety, insomnia, tachycardia). Acidification of the urine (e.g. with ammonium chloride) has the opposite effect. 

Berkowitz RB, Connell JT, Dietz AJ, Greenstein SM, Tinkelman DG (1989) The effectiveness of the non-sedating antihistamine loratadine plus pseudoephedrine in the symptomatic management of the common cold. Arm Allergy 63 336-339 Bliss TV, Lomo T (1973) Long-lasting potentiation of synaptic transmission in the dentate area of the anaesthetized rabbit following stimulation of the perforant path. J Physiol 232 331-356 Brimblecombe RW (1979) Behavioral tests in acute and chronic toxicity studies. Pharmacol Ther 5 413 15... 

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