Unit 3 - Ibuprofen and Paracetamol

3.1 Introduction

At the end of this session you will be able to:

1. Understand what Reye’s syndrome is and what implications this has for management of children’s pain and fever.

Ibuprofen and Acetaminophen (Paracetamol)

Ibuprofen and paracetamol are the two most common over-the-counter medications used to treat pain and fever in babies and children. Aspirin is not recommended in children under age 16, due to implications in the development of Reye’s syndrome. (Porter et al 1990).

For more information on Reyes syndrome, see the National Reyes Syndrome Foundation UK  and also Medline Plus

3.2 Pharmacokinetics, side effects and efficacy

At the end of this session you will be able to:

1. Compare and contrast ibuprofen and paracetamol as drugs that can be used in the management of pain and fever

In addition you will be able to:

2. outline the key ways in which the two drugs work and relate this back to what you learnt in section on the pathophysiology of pain

3. Identify the efficacy of the two drugs in relation to fever management, anti-inflammatory and analgesic effects

Both ibuprofen and paracetamol have an affect on the action of prostaglandins in the body. Prostaglandins are the chemicals responsible for pain, swelling and inflammation and are produced in response to injury or illness.

For further information on Acetaminophen (new recommended name for Paracetamol) and ibuprofen see the following:
Acetaminophen and ibuprofen in the management of fever and mild to moderate pain in children. For product information on Nurofen for Children

For information on how to administer Nurofen for Children suspension

Ibuprofen and paracetamol work in different ways to alleviate pain and fever and have different pharmacokinetics:

Ibuprofen is a non-steroidal anti inflammatory drug (NSAID). It works by blocking the action of the cyclooxygenase enzymes peripherally known as COX 1 and COX 2. Cyclooxygenase is involved in the production of various chemicals in the body, some of which are prostaglandins.

Paracetamol works to reduce the perception of pain by inhibiting the synthesis of prostaglandins cerebrally. Paracetamol does not alleviate inflammation.

Numerous studies have studied the safety and efficacy of ibuprofen (Lesko 2003) and paracetamol (Meremikwu & Oyo-Ita, 2002; Losek, 2004) in the treatment of pain and fever in infants and both have proven to be safe, efficacious and well tolerated (Wahba, 2004) (see also Table 7).

Whilst both drugs have good effects studies show ibuprofen can reduce fever more effectively and for a longer duration than paracetamol (Czaykowski et al, 1994; Goldman et al., 2004). Ibuprofen has also demonstrated a significant reduction in temperature after just 15 minutes, in the treatment of hospitalised children with pyrexia (Pelen et al, 1998).

Safety and tolerability of ibuprofen vs paracetamol

Paracetamol is often perceived to be better tolerated and safer than ibuprofen. However, clinical evidence demonstrates that ibuprofen is in fact well tolerated in babies and children, with similar GI tolerability to paracetamol in the treatment of fever and pain (Czaykowski et al, 1994; Walson et al, 1989; Autret E et al, 1994; Greene JJ et al, 1994). The largest comparison of the tolerability of ibuprofen and paracetamol is the Boston University Fever Study (Lesko 1995) . 84, 192 children aged 6 months to 12 years received either paracetamol (12mg per kg) or ibuprofen (5 or 10 mg per kg) to treat symptoms of acute febrile illness. The incidence of adverse events with both agents was low and similar (see table 7)

Ibuprofen and asthma:

The link between ibuprofen and asthma has long been debated amongst health care professionals.

There is a wealth of research that suggests that there is no greater risk of inducing asthma with ibuprofen than there is with paracetamol (Lesko et al 2003 and Losek 2004). In particular, a recent US study of almost 2,000 children determined that short-term use of ibuprofen showed no adverse effect on either renal function or asthma morbidity (Lesko 2002).
Note that the British National Formulary states that NSAIDS are contraindicated in patients in whom asthma has been precipitated by aspirin or any other NSAID

Gastrointestinal Tolerability of Ibuprofen:

Concerns about potential GI effects with ibuprofen have arisen due to its classification as an NSAID. However, in reality, ibuprofen is associated with a very low level of GI side effects. The Boston University fever study (Lesko 1995) demonstrated that the risks of gastrointestinal bleeding with ibuprofen and paracetamol were not statistically significantly different.

There are dangers associated with the administration of any medication and despite the fact that these are over-the-counter drugs, risks have been identified (Plaisance 2000).

Overdosage (with therapeutic intent) of paracetamol has been described in the literature and particular care needs to be taken to avoid this in young dehydrated or malnourished children (Watts et al. 2003). Antipyretics should be used with caution and used selectively.

The practice of alternating ibuprofen and paracetamol to manage children’s fever has been advocated (Mofenson et al, 1998). However, there is little evidence to support this approach (Carson, 2003) and it brings with it serious problems of potential overdosage (Mayoral et al, 2000) and the potential for confusion.

Considering that there is so little evidence as to the benefits to reducing fever it is vital that any medication utilised is age-appropriate, therapeutic, and given at a safe dose.