Effect of naproxen and sulindac on blood pressure response to atenolol

Adverse drug interactions involving common prescription and over-the-counter analgesic agents

BACKGROUND

Eight analgesic preparations with approved indications for acute pain were among the top 200 drugs prescribed in the United States in 2006. In addition, an estimated 36 million Americans use over-the-counter (OTC) analgesics daily. Given this volume of use, it is not surprising that a number of drug interactions involving analgesic drugs have been reported.

OBJECTIVES

This article examines the pharmacologic factors that enhance the clinical relevance of potential drug interactions and reviews the literature on drug interactions involving the most commonly used analgesic preparations in the United States.

METHODS

A PubMed search was conducted for English-language articles published between January 1967 and July 2007. Among the search terms were drug interactions, acetaminophen, aspirin, ibuprofen, naproxen, celecoxib, NSAIDs, hydrocodone, oxycodone, codeine, tramadol, OTC analgesics, alcohol, ethanol, antihypertensive drugs, methotrexate, warfarin, SSRIs, paroxetine, fluoxetine, sertraline, citalopram, serotonin syndrome, MAOIs, and overdose. Controlled clinical trials, case-control studies, and case reports were included in the review.

RESULTS

A number of case reports and well-controlled clinical trials were identified that provided evidence of the relatively well known drug-drug interactions between prescription/OTC NSAIDs and alcohol, antihypertensive drugs, high-dose methotrexate, and lithium, as well as between frequently prescribed narcotics and other central nervous system depressants. In contrast, the ability of recent alcohol ingestion to exacerbate the hepatotoxic potential of therapeutic doses of acetaminophen is not supported by either case reports or clinical research. Use of ibuprofen according to OTC guidelines in patients taking cardioprotective doses of aspirin does not appear to interfere with aspirin's antiplatelet activity, whereas chronic prescription use of ibuprofen and other NSAIDs may interfere. Low-dose aspirin intake appears to abolish the gastroprotective effects of cyclooxygenase-2-selective inhibitors, including celecoxib. There is evidence of other less well known and potentially clinically significant drug-drug interactions, including the ability of selective serotonin reuptake inhibitors to inhibit the analgesic activity of tramadol and codeine through inhibition of their metabolic activation, to induce serotonin syndrome when used chronically in the presence of high doses of tramadol through synergistic serotonergic action, and to increase the potential for gastrointestinal bleeding associated with NSAID therapy through additive or supra-additive antiplatelet activity.

CONCLUSIONS

Considering the widespread use of analgesic agents, the overall incidence of serious drug-drug interactions involving these agents has been relatively low. The most serious interactions usually involved other interacting drugs with low therapeutic indices or chronic and/or high-dose use of an analgesic and the interacting drug.

Antihypertensive therapy: special focus on drug interactions

Today, the lifetime risk of patients aged 55-65 years to receive antihypertensive drugs approaches 60%. Yet, recent trials suggest that hypertension is not adequately controlled in the majority of patients. The prevalence of hypertension increases with advancing age, as does the prevalence of comorbid conditions and the total number of medications taken. Multi-drug therapy, advancing age and comorbid conditions are also key risk factors for adverse drug reactions and drug interactions. In this review, the authors evaluate the most frequently used antihypertensive drugs (diuretics, beta-adrenergic blockers, angiotensin-converting enzyme inhibitors, calcium channel blockers, angiotensin II receptor Type 1 blockers and alpha-adrenergic blockers) with special reference to pharmacodynamic and pharmacokinetic drug interactions. As the spectrum of drugs prescribed is constantly changing, safety yesterday does not imply safety today and safety today does not imply safety tomorrow. Furthermore, therapeutic efficacy should not be neglected over concerns regarding drug interactions. Many patients are at risk of clinically relevant drug interactions involving antihypertensive drugs but, presently, even more patients may be at risk of suffering from the consequences of their inadequately treated hypertension. In this respect, the authors discuss controversial viewpoints on the overall clinical relevance of drug interactions occurring at the level of cytochrome P450 metabolism.

Over-the-counter analgesics and antipyretics: a critical assessment

BACKGROUND

It is just 100 years since the introduction of aspirin to medicine. Since then, aspirin and its derivatives have been joined by acetaminophen, and the nonsteroidal anti-inflammatory drugs--ibuprofen, naproxen sodium, and ketoprofen--as the only over-the-counter (OTC) agents approved by the US Food and Drug Administration for the short-term treatment of pain, headache, dysmenorrhea, and fever. Recently the prescription use of aspirin has expanded to include a number of antiplatelet indications.

OBJECTIVE

The purpose of this paper is to review critically the history, mechanisms of action, efficacy, and tolerability of OTC analgesic and antipyretic products. Relatively new and potential future indications for these drugs are also discussed.

CONCLUSION

Although all of the OTC analgesic/antipyretic agents seem to share a common mechanism of prostaglandin inhibition, there are important differences in their pharmacology, efficacy, and side-effect profiles. Considering their often-unsupervised use, the risk-benefit ratio of this class of drugs has been extremely favorable. However, when used inappropriately, even these drugs pose significant risks to certain patient populations.

Clinical pharmacokinetics of sulindac. A dynamic old drug

Sulindac is a nonsteroidal anti-inflammatory drug (NSAID) of the indene acetic acid class. The absorption of sulindac is rapid when given orally. Sulindac is reversibly metabolised to sulindac sulphide which has anti-inflammatory and analgesic properties and is irreversibly metabolised to sulindac sulphone which has been suggested to possess antiproliferative effects against tumours. Sulindac and its sulphide and sulphone metabolites bind extensively to plasma albumin. Sulindac is eliminated following bio-transformation; sulindac and sulindac sulphone and their respective glucurooconjugated metabolites are excreted in urine; however only a small amount of the sulindac sulphide metabolite is eliminated in urine. Following long term twice daily administration both sulindac and its metabolites accumulate in plasma. Both patients with cirrhosis and the elderly demonstrate elevated concentrations of all species upon long term sulindac administration as compared with a single dose. The disposition of sulindac and its metabolites may be tied to renal function. In end-stage renal disease, increased free fractions of all species and accumulation of the sulphide and sulphone metabolites, and to a lesser extent sulindac, occurs. Significant drug interactions have been demonstrated for dimethylsulphoxide, cyclosporin, furosemide (frusemide), hydrochlorothiazide, methotrexate and cholestyramine.

Nonprescription drugs and hypertension. Which ones affect blood pressure?

Hypertensive patients should be aware of the possible effects of nonprescription medications on blood pressure control. For absolute safety, no adrenergic agents should be used. Nasal phenylephrine hydrochloride is probably the safest of these agents, and pseudoephedrine hydrochloride may also be safe. Phenylpropanolamine hydrochloride and ephedrine sulfate are probably best avoided. The effects of other adrenergic agents (eg, epinephrine) on blood pressure have not been clinically evaluated. Ibuprofen may elevate blood pressure if taken in maximum over-the-counter doses for more than a few days. The ethanol and sodium chloride content of nonprescription drugs taken in recommended doses does not appear to pose a great hazard.