Bilateral guaifenesin ureteral calculi

Drug-Induced Kidney Stones and Crystalline Nephropathy: Pathophysiology, Prevention and Treatment

Drug-induced calculi represent 1-2% of all renal calculi. The drugs reported to produce calculi may be divided into two groups. The first one includes poorly soluble drugs with high urine excretion that favour crystallisation in the urine. Among them, drugs used for the treatment of patients with human immunodeficiency, namely atazanavir and other protease inhibitors, and sulphadiazine used for the treatment of cerebral toxoplasmosis, are the most frequent causes. Besides these drugs, about 20 other molecules may induce nephrolithiasis, such as ceftriaxone or ephedrine-containing preparations in subjects receiving high doses or long-term treatment. Calculi analysis by physical methods including infrared spectroscopy or X-ray diffraction is needed to demonstrate the presence of the drug or its metabolites within the calculi. Some drugs may also provoke heavy intra-tubular crystal precipitation causing acute renal failure. Here, the identification of crystalluria or crystals within the kidney tissue in the case of renal biopsy is of major diagnostic value. The second group includes drugs that provoke the formation of urinary calculi as a consequence of their metabolic effects on urinary pH and/or the excretion of calcium, phosphate, oxalate, citrate, uric acid or other purines. Among such metabolically induced calculi are those formed in patients taking uncontrolled calcium/vitamin D supplements, or being treated with carbonic anhydrase inhibitors such as acetazolamide or topiramate. Here, diagnosis relies on a careful clinical inquiry to differentiate between common calculi and metabolically induced calculi, of which the incidence is probably underestimated. Specific patient-dependent risk factors also exist in relation to urine pH, volume of diuresis and other factors, thus providing a basis for preventive or curative measures against stone formation.

Acute renal failure after ingestion of guaifenesin and dextromethorphan

BACKGROUND

Guaifenesin is a common nonprescription medication that has been implicated in drug-induced nephrolithiasis. Dextromethorphan, a nonprescription antitussive found in some guaifenesin-containing preparations, is increasingly recognized as a substance of abuse by many youth and young adults. Renally excreted medications known to have poor solubility in urine have the potential to precipitate when ingested in large quantity, leading to acute obstruction of the ureters and renal failure.

OBJECTIVE

We describe the case of a 22-year-old male who developed severe bilateral flank pain, hematuria, and oliguria after an isolated recreational ingestion of guaifenesin and dextromethorphan.

CASE REPORT

The patient was found to have bilateral ureteral obstruction and acute renal failure, suspected to be secondary to precipitation of medication metabolites in the urine.

CONCLUSIONS

This case highlights the potential for acute renal failure secondary to guaifenesin and dextromethorphan abuse.

Urological complications of illicit drug use

Illicit drug use is prevalent worldwide; over 24 million people are estimated to have used recreational drugs during the past month in the UK and USA alone. Illicit drug use can result in a wide spectrum of potential medical complications that include many urological manifestations. To ensure optimal care and treatment, urologists need to be cognizant of these complications in their patients, particularly among youths. Ketamine uropathy is thought to affect over one-quarter of ketamine users and can lead to severe lower urinary tract symptoms, as well as upper tract obstruction. Cannabis use has been associated with an increased risk of bladder cancer, prostate cancer and nonseminomatous germ cell tumours in case-control studies. Fournier's gangrene has been reported following injection of heroin and cocaine into the penis. Excessive use of cough medicines can lead to the development of radiolucent stones composed of ephedrine, pseudoephedrine and guaifenesin. As the current evidence is mostly limited to case reports and case series, future epidemiological studies are needed to fully address this issue.

Recommendations for the Proper Use of Nonprescription Cough Suppressants and Expectorants in Solid-Organ Transplant Recipients

Objective

To describe the pharmacology and safety of oral over-the-counter cough suppressants and expectorants and to present recommendations for the use of these agents in solid-organ transplant recipients based on the potential for adverse drug reactions or drug-disease interactions.

Data Sources and Extraction

Data from journal articles and other sources describing the pharmacology and safety of over-the-counter cough suppressants and expectorants, drug-drug interactions with immunosuppressive agents, and drug-disease state interactions are reviewed.

Data Synthesis

Potential and documented drug-drug interactions between immunosuppressive agents and over-the-counter cough medications guaifenesin, dextromethorphan, diphenhydramine, and codeine were evaluated on the basis of pharmacokinetic and pharmacodynamic principles. Interactions between these cough medications and the physiological changes in the body following transplantation also were examined.

Conclusion

Diphenhydramine requires additional monitoring when used to treat cough in transplant recipients owing to its anticholinergic properties and the potential for interactions with cyclosporine. Dextromethorphan can be used in most transplant recipients, although greater caution should be exercised if the patient has undergone liver transplant or has liver impairment. Guaifenesin can be used in transplant recipients but should be used with caution in patients receiving kidney or lung transplants and in patients with renal impairment. Codeine combined with guaifenesin is another option for cough and can be used in most transplant patients although those with reduced renal function should be monitored carefully for adverse events.

Case report: anaphylactic reaction to guaifenesin

Adverse drug reactions lead to a significant number of hospital admissions each year and thus contribute to the overall financial burden of health care. Some of these drug reactions are allergic responses. As the overall predictability of allergic responses to drugs remains low, efforts to improve our understanding of the processes underlying these responses continue as we strive toward the ultimate goal of primary prevention. Allergic reactions range from mild pruritic to severe systemic anaphylactic responses. We report a case of a young healthy man who developed an anaphylactic reaction to an over-the-counter expectorant. A skin test showed that the patient had an immunoglobulin E-mediated allergic response to guaifenesin, one of the components of commonly available cough medications. Our review of published literature showed that this is the first report of a severe allergic response to guaifenesin.