Analgesic recommendations when treating musculoskeletal sprains and strains.

ABSTRACT

Physiotherapists are often asked to provide treatment and advice for musculoskeletal sprains and strains. According to some best-practice guidelines, simple analgesics can be effective in many cases but there is often debate as to which analgesics are most appropriate for these injuries. As physiotherapists are primary care practitioners, a good current knowledge of these guidelines and the relevant medications may aid in providing appropriate advice to their patients. Recently there has been reclassification of some analgesics, allowing patients to purchase these medications without consulting a health professional, and patients often perceive these medications to be safe.

This paper aims to discuss pharmaceutical options for these types of injuries with a focus on those available without a prescription; to identify appropriate indications and contraindications of these medications; to discuss the controversy surrounding the use of anti-inflammatory medications in the immediate post-injury period; and to discuss patients' access to these medications. Braund R, Abbott JH (2007): Analgesic choice when treating musculoskeletal sprains and strains. New Zealand Journal of Physiotherapy 35(2): 54-60.

Key Words: Sprains and Strains; Analgesics; Anti-inflammatory agents, Non-steroidal

INTRODUCTION

Of all musculoskeletal injuries, sprains and strains are the most common, with ankle sprains alone reported to account for 15 percent of all sports injuries (Almekinders 1999, Liu and Nguyen 1999, McGriff-Lee 2003, Rubin and Sallis 1996). While such injuries are usually considered minor, they should be taken seriously due to their potential to cause chronic pain and functional instability (Almekinders 1999, Osborne and Rizzo 2003). Musculoskeletal injuries of all types are often painful, so patients often seek general sale analgesics and other treatments.

Appropriate treatment of sprains and strains in the first 48 hours after the injury includes rest, ice, compression, and elevation (RICE) (Harvey 1997, McGriff-Lee 2003). RICE should be the mainstay of treatment in the initial period following injury and HARM (Heat, Alcohol, Running/ Resuming exercise, and Massage) should be avoided. Oral analgesics are recommended for the treatment of pain in many musculoskeletal injuries (Australian Acute Musculoskeletal Guidelines Group 2003, Accident Compensation Corporation Guidelines 2004a&b, Airaksinen et al 2006), but caution should be used as they can mask symptoms that may suggest more severe damage, and may cause uncomfortable side-effects or serious adverse events.

Many primary healthcare professionals, including physiotherapists, pharmacists and others, will be approached by patients seeking advice and treatment, and are often asked by their patients to make recommendations. Currently, recommending medication is considered outside physiotherapists' general scope of practice (Abbott 2003). However, this is also the case in Australia, yet there is evidence that physiotherapists there often recommend medications, principally simple analgesics and non-steroidal anti-inflammatory drugs (NSAIDs) (Grimmer et al 2002). It appears likely that the same occurs in New Zealand (Cornford et al 2007). It has been argued that health professionals need to be aware of the side-effects of, and precautions in the use of these medications, as many patients under their care are taking them (Benson et al 1995).

The reclassification of some medications, such as the change in status of ibuprofen becoming a general sales medicine (April 2004) and stronger codeine combination products available from pharmacies (May 2005), may indicate the need for physiotherapists to update their knowledge of analgesic and anti-inflammatory medications available in New Zealand,

MEDICATION AVAILABILITY

Because the symptoms of sprains and strains include pain and inflammation, analgesics and anti-inflammatories may be indicated. There are currently several analgesic and anti-inflammatory medication options available without a prescription in New Zealand. Medications are classified into groups defining where they can be sold based on their relative safety and therefore the need for health professional supervision (See table 1). Review of the classification of some medications leads to a shift in how they can be sold. For example, ibuprofen 200mg was reclassified from a Pharmacy-only Medicine to a General-sale Medicine in April 2004. This change has been met with some controversy as this medicine can now be purchased from any retail outlet and some question whether it is sufficiently safe for such distribution. However, ibuprofen in this strength is available for general purchase in a number of other countries. As a primary care provider, a physiotherapist may be the only healthcare provider a patient taking general-sale ibuprofen sees, therefore it serves the best interests of the patient's safety if the physiotherapist is aware of the precautions of this common medication, and is alert for the signs and symptoms of side-effects.

MEDICATIONS AVAILABLE WITHOUT A PRESCRIPTION

Paracetamol 

Paracetamol is classified as a general sale medicine due to its relative safety. Perhaps due to its wide availability, there is often a perception that paracetamol is a less effective analgesic (Boger and Jones 2005), however the evidence would suggest it is equivalently effective to NSAIDs (Gotzsche 2000). It does have both analgesic and antipyretic effects, and differs from the majority of NSAIDs in that it lacks significant anti-inflammatory activity (Aronoff et al 2006).

While its exact mechanism of action is not clearly defined (Sachs 2005) paracetamol appears to exert some of its effects via inhibition of prostaglandin synthesis within the central nervous system (Aronoff et al 2006). One large clinical trial that compared NSAIDs with paracetamol for musculoskeletal injuries found no difference in efficacy (Woo et al 2005). Indeed there is growing support for using paracetamol as first-line treatment as it may be just as effective an analgesic as NSAIDs and will not increase bleeding into the injury site or potentially impair healing (Paoloni and Orchard 2005, Rahusen et al 2004). Due to its efficacy, cost and side-effect profile, paracetamol should be regarded as the initial choice for most mild to moderate acute pain of non-specific origin (Sachs 2005). Paracetamol is generally considered safe in analgesic doses. The main important potential side effect is liver toxicity at high doses or in susceptible patients, for example excessive alcohol use (Langford 2006).

Codeine

Codeine, an opiate analgesic, is considered a pro-drug and requires metabolism in the body for its analgesic effect (Sachs 2005). The individual variability in this metabolic activity may impact on its analgesic effect (Vree et al 2000) and so some patients will not find it effective. An estimate in the UK suggests 9% of patients will be poor metabolisers (Williams et al 2001). Codeine is currently available from pharmacies over the counter, but only in combination products, with either paracetamol or ibuprofen. An increased analgesic effect (synergistic effect) of the two analgesic agents occurs when used in combination (de Craen et al 1996, Moore et al 1997). As with all opiates, constipation and drowsiness can be significant side-effects. In 2005, a combination product with 15mg of codeine was introduced for sale in pharmacies, with a Pharmacy-only status, which is an increase from the 8mg dose previously available.

NSAIDs

Within this group there are varying degrees of regulations on the availability of individual drugs. For example topical preparations of ibuprofen and diclofenac are currently given general-sale status, as is ibuprofen 200mg when sold in packs of less than 25 dose units. Oral diclofenac has several classifications depending on tablet strength, including Pharmacist-only at strengths of 25mg per tablet and prescription-only status at higher strengths.

NSAIDs are often used in musculoskeletal conditions due to their anti-inflammatory effects, where they act to inhibit the production of prostaglandins (pro-inflammatory mediators) via their inhibition of the enzyme cyclooxygenase (COX) (Stanley and Weaver 1998). The COX enzymes are also important for gastrointestinal and renal protection and this is one of the reasons that NSAIDs have many of their side-effects, such as serious upper gastro-intestingal (GI) complications, nephrotoxicity and renal failure (Pham and Hirschberg 2005). NSAIDs are associated with a 5-to-10-fold increase in serious peptic ulcers, peptic ulcer haemorrhage, and GI perforations (Schaffer et al 2006, Garcia Rodriguez & Hernandez-Diaz 2002). It is important to note that NSAIDs can also cause renal failure in dehydrated patients: there have been numerous reports of athletes taking NSAIDs prior to sport becoming dehydrated, resulting in renal failure requiring dialysis, or even death (Cronin et al 2006, Farquhar et al 1999, Ratliff et al 2002).

COX-2 specific NSAIDs were developed after it was shown that COX-2 was increased during inflammation and that by targeting this enzyme more specifically and sparing the gastro-protective COX-1 enzyme, there might be a reduced incidence of gastrointestinal problems such as peptic ulcers. The COX-2 specific NSAIDs have recently been under the spotlight with emerging evidence that there is an increased risk of cardiovascular problems. This has led to reinvestigation of the cardiovascular risks for traditional NSAIDs and it appears that there is an increased risk of cardiovascular complication with all NSAIDs (Borer and Simon 2005, Pham and Hirschberg 2005).

Most NSAIDs including the COX-2 inhibitors are prescription-only medications although there are several available without a prescription (see table 2). Interestingly, there seems to be no important differences in efficacy between the different NSAIDs, but there may be differences in their relative toxicity (Henry et al 1996). In fact a major meta-analysis suggested that as 'there are no important differences in efficacy, choice of first line treatment with these drugs should be based on their relative toxicity' (Henry et al 1996). This statement has been supported by current clinical evidence showing that there is no difference in efficacy between different NSAIDs, but that there may be differences in adverse effects (Gotzsche 2006).

Ibuprofen appears to have the best safety profile in terms of lower risk of gastrointestinal complications (Henry et al 1996, Sachs 2005) but only when used at low doses. It has been reclassified to a general-sale status in limited pack sizes, but there is no limit to how many packs can be purchased. While it is considered one of the 'safer' NSAIDs it is important to remember that the incidence of GI and other side-effects are still increased, but to a lesser extent than other NSAIDs. These medications can still be harmful in susceptible patients, including the elderly, those with sensitivity to NSAIDs, those with previous GI history, and those who take high doses, and they can also exacerbate asthma symptoms including the potential for severe respiratory distress. It has been shown that increasing the dose of all NSAIDs may only slightly increase analgesic efficacy to a maximum ceiling, but significantly increases the side-effects (Gotzsche 2000). As there is no evidence that NSAIDs are more effective than paracetamol in acute musculoskeletal conditions (Gotzsche 2000), many treatment guidelines recommend simple analgesics in most circumstances (Accident Compensation Corporation Guidelines 2004b).

Topical NSAIDs

There has been much debate about topical NSAIDs, mainly focusing on efficacy and side-effect profile. Topical NSAIDs have lower plasma concentrations when compared to orally administered NSAIDs although it is thought that the level in soft tissue will still exert an anti-inflammatory effect (Vaile and Davis 1998) with evidence of analgesic efficacy above simply a placebo effect, and no difference in efficacy compared to oral NSAID (Mason et al 2004a, Mason et al 2004b, Moore et al 1998).

While the anticipated lower plasma concentrations may suggest a lower systemic side-effect profile there have been reports of adverse GI events, as well as asthma exacerbation and acute renal impairment with topical products (Moore et al 1998). It is also important to note that there will be a small percentage of patients who experience adverse cutaneous reactions.

Once again, as these are general-sale medications many people forget about the potential for adverse reactions in susceptible patients, although both local and sysematic adverse events appear to be infrequent (6% and 3% respectively) (Mason et al 2004b). There is, however, significant variation in the amount of topical medication that people apply, the number of times they apply it and in the size of the area to which it is applied. All of these can potentially impact plasma concentrations and lead to systemic side-effects. These products should only be applied three to four times a day depending on strength of product used (Joint Formulary Committee, 2007). From a practical viewpoint it is important to note that those who apply these directly to their patients will also be at risk of potential side-effects, unless they protect themselves from contact with the drug using gloves.

Current controversy surrounding use of anti-inflammatory medications in the initial post-injury phase

The early and aggressive use of NSAIDs to treat acute musculoskeletal injuries including sprains and strains has been common in the past, in order to halt the inflammation that leads to pain, swelling and loss of joint mobility. However, during the first 24-48 hours following injury, the inflammatory response is crucial for the recruitment and activation of inflammatory mediators that act to remove tissue damage and begin the process of tissue repair and regeneration. This process reaches its maximum at 48 hours. Inflammation at the injury site acts to limit the amount of damage (e.g. haemostasis to prevent bleeding), to protect from further damage (e.g. swelling to immobilise the joint) and to initiate healing (via macrophages to remove debris and initiate regeneration) (Hertal 1997, Jarvinen et al 2005, Tidball 2005).

Inflammation is a necessary component in the healing process and without it repair would not take place (Harvey 1997, Stovitz and Johnson 2003). Thus, decreasing inflammation may impair the healing process and result in a delay of tissue repair (McGriff-Lee 2003, Reynolds et al 1995). There is significant evidence to suggest that if these medicines are used too early following injury, they will reduce the inflammatory response and may actually delay acute healing, slow muscle regeneration and compromise long-term healing (Almekinders 1999, Hertal 1997, Stovitz and Johnson 2003). There is also potential for increased bleeding and swelling at the site of injury due to NSAIDs decreasing platelet aggregation (Mautner 2004).

RECOMMENDATIONS

RICE plays a vital role in the treatment of sprains and strains as the rest acts to minimise further damage, bleeding and swelling is decreased by the ice, compression and elevation.

The World Health Organisation (WHO) developed an "analgesic ladder" as a step-wise approach to pain management in cancer patients. This ladder has been applied to musculoskeletal pain and further adapted by Boger and Jones (2005) to guide the safe and effective use of medications for the relief of pain in musculoskeletal conditions (Figure 1). In general, patients with musculoskeletal pain should begin at level one, and only if relief is not achieved should the next higher level be engaged.

[FIGURE 1 OMITTED]

The mainstay of analgesic treatment of musculoskeletal sprains and strains should be paracetamol due to its efficacy, good safety profile at therapeutic doses, cost-effectiveness and availability. The addition of codeine may provide analgesic benefit without the disruption of inflammation. NSAIDs have their greatest benefit in pain that is the result of excessive or uncontrolled inflammation such as rheumatoid arthritis. The analgesic benefits of NSAIDs in acute musculoskeletal conditions may be best realised after inflammation needed to initiate healing has passed. According to the analgesic ladder (Figure 1) paracetamol should first be tried: if ineffective, when taken as recommended, codeine should be added, and only after that (step 2) should NSAIDs be considered. It has been recommended that NSAIDs not be started until 48 hours after injury (Braund 2006). When an NSAID is used, consideration should be given to the relative toxicity and those with a safer toxicity profile should be chosen (i.e diclofenac or ibuprofen). Precaution should always be taken in those patients with a history of gastric upset, asthma exacerbation and sensitivity to other NSAIDs and a realisation that these may still occur in susceptible patients even at low doses.

As providing advice to patients regarding purchasing, taking or adjusting medications is outside the general scope of physiotherapy practice in New Zealand, we recommend that referral to a pharmacist or medical practitioner is currently best practice for physiotherapists. This avoids unlawfully contravening the general scope of physiotherapy practice and medico-legal liability (Abbott 2003, S Begg, personal communication 2007). Physiotherapists may convey to patients that research and best-practice guidelines recommend medications for pain relief, and inquire whether the patient has access to step 1 medication (Figure 1). If the patient has, and is taking, step 1 medications, recommend the patient follow the instructions supplied with that medication. Indications for referral to a pharmacist include patients with mild to moderate pain of musculoskeletal origin who are not taking pain medications, or who are taking step 1 to step 3 medications. A suitable referral form for referral to a pharmicist should include at least two details identifying the patient (e.g. name plus date of birth), your diagnosis, a request that the pharmacist consult with the patient and provide recommendations, your name and signature, and the date. Retain a copy for your patient records. An example is shown in Figure 2. Indications for referral to a medical practitioner include include patients with moderate to severe pain, failure of step 3 medications to control musculoskeletal pain, pain of non-musculoskeletal origin, pain suspected to be complicated by non-musculoskeletal factors, significant comorbidities, age over 65, polypharmacy, or other concerns. A suitable referral to a medical practitioner should include at least two details identifying the patient (e.g. name plus date of birth), a concise summary of the patient's history and examination findings, your diagnosis, a description of your concerns, your reasons for referral, your plan of care from this point (i.e. your intention to continue physiotherapy concurrently, or transfer care over to the doctor), your name and signature, and the date. Retain a copy for your patient records.

[FIGURE 2 OMITTED]

Key Points

* Due to its efficacy, low cost and low side-effect profile, paracetamol should be regarded as the initial choice for most mild to moderate acute pain of non-specific origin.

* There are no important differences in efficacy within the NSAIDs and so choice of treatment with these drugs should be based on their relative toxicity.

* Ibuprofen appears to have the best safety profile of the NSAIDs in terms of lower risk of gastrointestinal complications, but only when used at low doses.

* All medications have the potential for side-effects in susceptible people, even at low doses.

* Under current New Zealand law, advising patients to purchase, consume or administer medication is outside the general scope of physiotherapy practice. Referral to a pharmacist or medical practitioner is recommended. A well-constructed written referral is highly recommended.

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ADDRESS FOR CORRESPONDENCE

Rhiannon Braund, School of Pharmacy, University of Otago, PO Box 913, Dunedin. Email: [e-mail]. ac.nz. Phone: [phone].

Rhiannon Braund, BSc (Biochemistry), BPharm, RegPharmNZ, MPS

Clinical Pharmacy Practice Lecturer, School of Pharmacy, University of Otago

J. Haxby Abbott, PhD, MScPT, FNZCP

Senior Research Fellow, Clinical Research Development

New Zealand Centre for Physiotherapy Research, University of Otago

Table 1. New Zealand Medications Classification

Classification                Definition

General Sale Medicines        May be sold from any retail outlet

Pharmacy or Pharmacy-only     May only be sold from a pharmacy or
Medicines                     hospital

Pharmacist-only Medicines     May only be sold by a pharmacist in
(also called Restricted       a pharmacy or hospital
Medicines)

Prescription Medicines        May only be sold or supplied pursuant
                              to a prescription

Classification                Example

General Sale Medicines        Paracetamol 500mg tablets
                              Ibuprofen 200mg (limited pack
                              size)
                              Topical NSAIDs

Pharmacy or Pharmacy-only     Liquid paracetamol
Medicines                     Paracetamol and Codeine
                              combination products

Pharmacist-only Medicines     Diclofenac 25 mg tablets
(also called Restricted
Medicines)

Prescription Medicines        Diclofenac 75mg extended release
                              tablet

Table 2. Non-Prescription Analgesics
Joint Formulary Committee (2007)
BNF 53ed

Class          Action          Side-effects           Precautions

Non-opioid     analgesic       Considered safe but    Caution in
analgesic      antipyretic     potential for liver    patients with
                               toxicity in high or    hepatic or renal
                               extended doses         impairment

NSAIDs         analgesic       Gastrointestinal       Not
               antipyretic     problems               recommended in
               anti-           -nausea, diarrhoea,    pregnancy.
               inflammatory    bleeding and           Caution in the
                               ulceration             elderly, those
                               Renal impairment,      with sensitivity
                               fluid retention,       to other NSAIDs,
                               increased blood        those with
                               pressure,              renal, cardiac
                               angioedema, asthma     or hepatic
                               exacerbation,          impairment
                               brochospasm,           and those with
                               hypersensitivity       coagulation
                               reactions, hearing     defects
                               disturbances and
                               others

Opioid         analgesic       Constipation           Not
analgesic                      Drowsiness             recommended in
                                                      pregnancy

Specific       Usual analgesic dose
Medication     range

Paracetamol    0.5-1 g every 4-6
               hours
               max of 4g per day

Aspirin        0.3-1 g every 4 hours

Diclofenac     25-50mg three times
               a day or 75mg twice
               daily
               max of 150mg per
               day

Ibuprofen      400-600mg three
               times a day
               max of 2.4g per day

Mefanaminc     500mg three times
Acid           a day

Naproxen       500mg initially then
               250mg every 6-8
               hours

               max of 1.25g per
               day

Codeine        30-60mg every 4
               hours
               max of 240mg per
               day