A teenager with severe asthma exacerbation following ibuprofen

Lack of Major Involvement of Common CYP2C Gene Polymorphisms in the Risk of Developing Cross-Hypersensitivity to NSAIDs

Cross-hypersensitivity to non-steroidal anti-inflammatory drugs (NSAIDs) is a relatively common, non-allergic, adverse drug event triggered by two or more chemically unrelated NSAIDs. Current evidence point to COX-1 inhibition as one of the main factors in its etiopathogenesis. Evidence also suggests that the risk is dose-dependent. Therefore it could be speculated that individuals with impaired NSAID biodisposition might be at increased risk of developing cross-hypersensitivity to NSAIDs. We analyzed common functional gene variants for CYP2C8, CYP2C9, and CYP2C19 in a large cohort composed of 499 patients with cross-hypersensitivity to NSAIDs and 624 healthy individuals who tolerated NSAIDs. Patients were analyzed as a whole group and subdivided in three groups according to the main enzymes involved in the metabolism of the culprit drugs as follows: CYP2C9, aceclofenac, indomethacin, naproxen, piroxicam, meloxicam, lornoxicam, and celecoxib; CYP2C8 plus CYP2C9, ibuprofen and diclofenac; CYP2C19 plus CYP2C9, metamizole. Genotype calls ranged from 94 to 99%. No statistically significant differences between patients and controls were identified in this study, either for allele frequencies, diplotypes, or inferred phenotypes. After patient stratification according to the enzymes involved in the metabolism of the culprit drugs, or according to the clinical presentation of the hypersensitivity reaction, we identified weak significant associations of a lower frequency (as compared to that of control subjects) of CYP2C8*3/*3 genotypes in patients receiving NSAIDs that are predominantly CYP2C9 substrates, and in patients with NSAIDs-exacerbated cutaneous disease. However, these associations lost significance after False Discovery Rate correction for multiple comparisons. Taking together these findings and the statistical power of this cohort, we conclude that there is no evidence of a major implication of the major functional CYP2C polymorphisms analyzed in this study and the risk of developing cross-hypersensitivity to NSAIDs. This argues against the hypothesis of a dose-dependent COX-1 inhibition as the main underlying mechanism for this adverse drug event and suggests that pre-emptive genotyping aiming at drug selection should have a low practical utility for cross-hypersensitivity to NSAIDs.

Deep sequencing of prostaglandin-endoperoxide synthase (PTGE) genes reveals genetic susceptibility for cross-reactive hypersensitivity to NSAID

BACKGROUND AND PURPOSE

Cross-reactive hypersensitivity to nonsteroidal anti-inflammatory drugs (NSAIDs) is a relatively common adverse drug event caused by two or more chemically unrelated drugs and that is attributed to inhibition of the COX activity, particularly COX-1. Several studies investigated variations in the genes coding for COX enzymes as potential risk factors. However, these studies only interrogated a few single nucleotide variations (SNVs), leaving untested most of the gene sequence.

EXPERIMENTAL APPROACH

In this study, we analysed the whole sequence of the prostaglandin-endoperoxide synthase genes, PTGS1 and PTGS2, including all exons, exon-intron boundaries and both the 5' and 3' flanking regions in patients with cross-reactive hypersensitivity to NSAIDs and healthy controls. After sequencing analysis in 100 case-control pairs, we replicated the findings in 540 case-control pairs. Also, we analysed copy number variations for both PTGS genes.

KEY RESULTS

The most salient finding was the presence of two PTGS1 single nucleotide variations, which are significantly more frequent in patients than in control subjects. Patients carrying these single nucleotide variations displayed a significantly and markedly lower COX-1 activity as compared to non-carriers for both heterozygous and homozygous patients.

CONCLUSION AND IMPLICATIONS

Although the risk single nucleotide variations are present in a small proportion of patients, the strong association observed and the functional effect of these single nucleotide variations raise the hypothesis of genetic susceptibility to develop cross-reactive NSAID hypersensitivity in individuals with an impairment in COX-1 enzyme activity.

Working Towards an Appropriate Use of Ibuprofen in Children: An Evidence-Based Appraisal

Ibuprofen is the most widely used non-steroidal anti-inflammatory drug (NSAID) for the treatment of inflammation, mild-to-moderate pain and fever in children, and is the only NSAID approved for use in children aged ≥3 months. Its efficacy and safety profile have led to its increasing use in paediatric care, even without medical prescription. However, an increase of suspected adverse reactions to ibuprofen has been noted in concomitance with the raised, often medically unsupervised, consumption of the drug. The purpose of this work was a critical review of the paediatric literature over the last 15 years on side effects and adverse events associated with ibuprofen, in order to highlight circumstances associated with higher risks and to promote safe and appropriate use of this drug. The literature from 2000 to date demonstrates that gastrointestinal events are rare, but (when they occur) include both upper and lower digestive tract lesions. Dehydration plays an important role in triggering renal damage, so ibuprofen should not be given to patients with diarrhoea and vomiting, with or without fever. Likewise, ibuprofen should never be administered to patients who are sensitive to it or to other NSAIDs. It is contraindicated in neonates and in children with wheezing and persistent asthma and/or during varicella. Most of the analysed studies reported adverse events when ibuprofen was being used for fever symptoms or flu-like syndrome. Ibuprofen should not be used as an antipyretic, except in rare cases. Ibuprofen remains the drug of first choice in the treatment of inflammatory pain in children.

Short-term ibuprofen treatment and pulmonary function in children with asthma

OBJECTIVES

To investigate the association between ibuprofen use and pulmonary function in children with Asthma.

METHODS

Ninety 9- to 10-year-old children were classified into 3 groups: Study group, mild to moderate stable asthmatic children with self-reported aspirin allergy and no history of anaphylaxis; Allergy control group: atopic children (allergic rhinitis/atopic dermatitis); Healthy control group: non-atopic healthy children. None of the participants in the atopic and healthy control groups had a history of aspirin allergy. All received ibuprofen 4 times a day for 3 consecutive days. Forced expiratory volume in the first second (FeV1) and fractional exhaled nitric oxide (FeNO) measurements were performed before and after ingestion of ibuprofen daily for 3 days.

RESULTS

In the study group, a decrease in FeV1 and increase in FeNO levels were observed after taking ibuprofen for 2 days. The atopic control group showed only an increase in FeNO but not FEV1. In the healthy control group, both FeV1 and FeNO were unchanged from baseline.

CONCLUSION

The results showed that cross-reactive non-steroidal anti-inflammatory drug hypersensitivity may exist between ibuprofen and aspirin. This raises the possibility that asthma exacerbation could be mediated by ibuprofen ingestion.

Adverse drug reactions and drug-drug interactions with over-the-counter NSAIDs

Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen have a long history of safe and effective use as both prescription and over-the-counter (OTC) analgesics/antipyretics. The mechanism of action of all NSAIDs is through reversible inhibition of cyclooxygenase enzymes. Adverse drug reactions (ADRs) including gastrointestinal bleeding as well as cardiovascular and renal effects have been reported with NSAID use. In many cases, ADRs may occur because of drug-drug interactions (DDIs) between the NSAID and a concomitant medication. For example, DDIs have been reported when NSAIDs are coadministered with aspirin, alcohol, some antihypertensives, antidepressants, and other commonly used medications. Because of the pharmacologic nature of these interactions, there is a continuum of risk in that the potential for an ADR is dependent on total drug exposure. Therefore, consideration of dose and duration of NSAID use, as well as the type or class of comedication administered, is important when assessing potential risk for ADRs. Safety findings from clinical studies evaluating prescription-strength NSAIDs may not be directly applicable to OTC dosing. Health care providers can be instrumental in educating patients that using OTC NSAIDs at the lowest effective dose for the shortest required duration is vital to balancing efficacy and safety. This review discusses some of the most clinically relevant DDIs reported with NSAIDs based on major sites of ADRs and classes of medication, with a focus on OTC ibuprofen, for which the most data are available.

Optimising the management of fever and pain in children

Fever and pain in children, especially associated with infections, such as otitis media, are very common. In paediatric populations, ibuprofen and paracetamol (acetaminophen) are both commonly used over-the-counter medicines for the management of fever or mild-to-moderate pain associated with sore throat, otitis media, toothache, earache and headache. Widespread use of ibuprofen and paracetamol has shown that they are both effective and generally well tolerated in the reduction in paediatric fever and pain. However, ibuprofen has the advantage of less frequent dosing (every 6-8 h vs. every 4 h for paracetamol) and its longer duration of action makes it a suitable alternative to paracetamol. In comparative trials, ibuprofen has been shown to be at least as effective as paracetamol as an analgesic and more effective as an antipyretic. The safety profile of ibuprofen is comparable to that of paracetamol if both drugs are used appropriately with the correct dosing regimens. However, in the overdose situation, the toxicity of paracetamol is not only reached much earlier, but is also more severe and more difficult to manage as compared with an overdose of ibuprofen. There is clearly a need for advanced studies to investigate the safety of these medications in paediatric populations of different ages and especially during prolonged use. Finally, the recently reported association between frequency and severity of asthma and paracetamol use needs urgent additional investigations.

Samter's triad in childhood: a warning for those prescribing NSAIDs

Aspirin-exacerbated respiratory disease (AERD) has been recognized in adults with chronic asthma. Samter's triad is a subset of AERD where adult patients develop nasal polyps, asthma, and sensitivity to aspirin. This condition is thought not to occur before the third decade of life. We report a 13-year-old boy with nasal polyps who suffered a life-threatening exacerbation of asthma during a graded aspirin challenge. Resuscitation required positive pressure ventilation and inotropic support. Our observations confirm that classical Samter's triad can occur in children. We suggest that graded aspirin challenges in children are undertaken in a facility with equipment and staff trained for resuscitation. Consideration should be given to this rare complication when prescribing nonsteroidal anti-inflammatory drugs in the perioperative period. Suspicion of this condition merits referral to an immunologist for desensitization to aspirin.

An overview of clinical pharmacology of Ibuprofen

Ibuprofen was the first member of Propionic acid derivatives introduced in 1969. It is a popular domestic and over the counter analgesic and antipyretic for adults and children. Ibuprofen has been rated as the safest conventional NSAID by spontaneous adverse drug reaction reporting systems in the UK. This article summarizes the main pharmacological effects, therapeutical applications and adverse drug reactions, drug-drug interactions and food drug interactions of ibuprofen that have been reported especially during the last 10 years.

Non-steroidal anti-inflammatory drugs in orthopaedic and perioperative practice

Non-steroidal anti-inflammatory drugs are powerful and effective anti-inflammatory, analgesic and anti-pyretic drugs. They are routinely used in orthopaedic conditions and in the perioperative setting. They are however associated with potentially life-threatening side-effects and it is important to appreciate these before these medicines are administered. There is evidence suggesting that these drugs adversely affect bone formation, and this has implications for their use in patients with fractures and other pathologies that involve bone remodelling.

Systematic review and meta-analysis of the clinical safety and tolerability of ibuprofen compared with paracetamol in paediatric pain and fever

OBJECTIVE

The main aim of this review was to compare the tolerability and safety between ibuprofen and paracetamol when used as anti-pyretic and analgesic agents in children up to 18 years of age.

METHODS

MEDLINE (1950 to November 2008), EMBASE (1980 to November 2008), The Cochrane Library (2007, Issue 3), ACP Journal Club (1991 to November 2007) and Pascal (1987 to November 2007) were searched for randomised controlled trails (RCTs) (comparing ibuprofen and/or paracetamol with placebo), controlled observational studies and large case series comprised more than 1000 participants.

MAIN OUTCOME MEASURES

Adverse events (AEs) requiring discontinuation of medication; systemic reactions related to ibuprofen or paracetamol; serious AEs that are fatal, life-threatening or require hospitalisation; and serious AEs not requiring hospitalisation.

RESULTS

A total of 24 RCTs examined either ibuprofen and/or paracetamol versus placebo for AE data. Twelve other studies meeting our criteria were also included for AE data. Meta-analysis of systemic reactions demonstrated that tolerability and safety of ibuprofen was similar to placebo, as was paracetamol: ibuprofen versus placebo relative risk (RR) 1.39 (95% CI: 0.92, 2.10); paracetamol versus placebo RR 1.57 (95% CI 0.74, 3.33). A total of 2937 systemic AEs occurred in 21,305 patients taking ibuprofen compared with 1,466 systemic AEs in 11,164 patients taking paracetamol: RR 1.03 (95% CI 0.98, 1.10). There was no significant difference between the two groups. Narrative analysis of AE data identified conflicting evidence regarding hepatic injury with paracetamol and group A streptococcal infections with ibuprofen or paracetamol treatment.

CONCLUSIONS

Ibuprofen, paracetamol and placebo have similar tolerability and safety profiles in terms of gastrointestinal symptoms, asthma and renal adverse effects. While the study data investigated here may not reflect over-the-counter use, these results are still relevant in the context of any safety concerns relating to general ibuprofen or paracetamol treatment in children.

[Systemic analgesia adapted to the children's condition]

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.

Recent pharmacological advances in paediatric analgesics

Growth and development are two linked processes that distinguish children from adults. The use of size as the primary covariate during pharmacokinetic (PK) analyses allows exploration of the effects of age. Allometric scaling models have assisted understanding of the developmental clearance changes in common analgesic drugs such as paracetamol, morphine, tramadol and local anaesthetics agents. Single nucleotide polymorphisms (pharmacogenomics [PG]) and their impact on hepatic drug metabolism for opioids, tramadol, non-steroidal anti-inflammatory drugs (NSAIDs) and drug receptor responses are increasingly reported. Altered chemical structure or formulations of common analgesics alter pharmacodynamic (PD) effects enhancing safety and efficacy for NSAIDs by stereoselectivity and the addition of nitric oxide, for intravenous paracetamol by formulation and structural difference from propacetamol and for local anaesthetics through stereoselectivity. This article focuses upon recent data for analgesics used in paediatric pain management including paracetamol, NSAIDs, morphine, tramadol, amide local anaesthetics and ketamine. It centres on PK and clinical studies in neonates, infants and children. PG studies are acknowledged as potentially allowing individual drug therapy tailoring through a decrease in between-patient population variability, although the impact of PG in the very young is less certain. There are few data describing age-related PD changes in children despite recognition that the number, affinity and type of receptors or the availability of natural ligands changes with age.

Recent developments in the pharmacological management of pain in children

PURPOSE OF REVIEW

This review explores progress in developmental pharmacokinetics, pharmacogenomics and formulations of analgesic agents, and discusses potential implications for pain therapy.

RECENT FINDINGS

Characterization of the developmental pharmacokinetics of morphine, tramadol, paracetamol and nonsteroidal anti-inflammatory drugs has improved dosing in children. Oral sugar solutions have replaced the brandy/sugar pacifier and are effective for single painful events in neonates. Intravenous paracetamol offers increased dosing accuracy, and avoids absorption and bioavailability variability. New nitric-oxide-releasing versions of paracetamol and nonsteroidal anti-inflammatory drugs offer safer alternatives to their parent drugs with enhanced potency. Ketamine has come under a cloud for its possible effects on the neonatal developing brain, but it is being used increasingly in children to supplement opioids for pain after major surgery. Hopes that morphine analgesia may improve neurological outcome in premature babies have not materialized. Reports concerning chronic pain are generally case series and controlled trials are rare and nearly nonexistent in children.

SUMMARY

Unlicensed drug use in the very young will increase as familiarity increases. Pharmacogenomic studies have the potential to tailor drug therapy to the individual and decrease between-patient variability. Unfortunately, the pharmacodynamic knowledge in children of analgesic agents remains neglected and is usually extrapolated from adult data.