Oral and Topical Analgesics

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Analgesics that you can buy over the counter in a pharmacy will give temporary relief from the symptoms until the pain disappears on its own.

There are two ways in which analgesics work:

1) By stopping the production of chemicals that happen at the site of injury in order for the pain message not to be triggered at nerve endings.

2) By preventing the pain messages from being recognised once they reach the brain, they do this by blocking the chemicals produced in that part of the pain process. 


Some analgesics work in one way or the other, but there are some that can work in both ways at the same time.

Analgesics have different types of effects depending on their use, these are referred as:

1) Analgesic effect: reduces pain.
2) Anti-pyretic effect: reduces fever/high temperature.
3) Anti-inflammatory effect: reduces inflammation.

Non-Steroidal Anti-Inflammatory Drugs (NSAID):
These work against pain and inflammation by inhibiting an enzyme called cyclo-oxygenase. This is involved in the production of chemicals called prostaglandins, which triggers the inflammatory response in the body.

CLASSIFICATION OF MEDICINES:

(GSL) General Sales List: These are medicines that can be displayed outside pharmacy counters and supermarkets.

(P) Pharmacy: Medicines classified under pharmacy can only be bought at the counter and will always be kept within the pharmacy.

(POM) Prescription Only Medicine: These medicines can only be obtained by a doctor’s prescription.

There are different types of analgesics, all which have their own effects when use for managing different conditions and its symptoms.

Soluble analgesics are known to act faster than no-soluble ones.

ORAL ANALGESICS:

- Paracetamol (acetaminophen):
This is an overall effective painkiller, but just like any other painkiller it has its good and bad points.

Paracetamol has no action at the site of injury, only on the brain when used for relieving pain symptoms. It is an anti-pyretic medicine, meaning it reduces high temperatures.

It is useful to treat lots of different types of pains and can be used by anybody over three months of age, including people that suffer from asthma or stomach problems.

It can be used combined with other analgesics to make a stronger method of pain relief and is less likely to interact with other medicines that might need to be used at the same time.

It is not 100% understood of how paracetamol works, but it is believed that it works by blocking a new form of the cyclo-oxygenase enzyme called COX-3, that is found in the brain and spinal cord.

This is one of the possible explanations of why it does not help with inflammation and why it does not affect the digestive system.

Paracetamol comes in a 500 mg tablet form. As with all medicines, care must be taken in order not to overdose since the results could lead, in extreme cases, to death.
The maximum dose for an adult is 1000 mg (two 500mg tablets) at a time and not more than 4000 mg (eight 500mg tablets) in a 24-hour period, with at least four hours in between each dose.

For children aged 3 months up to 1 year of age, the dose is 60-120 mg/2.5-5 ml up to four times a day.
Children aged 1-5 years old can take 120-240 mg/5-10 ml up to four times a day.

Anything more than these doses can cause serious irreversible liver and kidney damage, and in some cases kill you if they cause organ failure.
Like with adult doses, be sure to leave a minimum of at least four-hours gap in between doses.

The effects of overdosing are never immediate and it can take up to three days for the symptoms of an overdose to become obvious, by which time it can be to late to reverse the damage.

Paracetamol is an ingredient found in many different products to treat pain so it is possible for people to take too much without realising it so please do take care when using medicines and always read the labels provided with your medicines.

- Aspirin:
This is also and overall effective painkiller with its own good and bad points too. It comes from the bark of the willow tree, and it is an old remedy that helps reduce swelling and inflammation.
It is classified as a Non-Steroidal Anti-Inflammatory Drug (NSAID) and it also works as an anti-pyretic medicine, which means it will help reduce temperature.
It works by blocking the production of pain-causing chemicals both at the site of injury and in the brain.

Aspirin tablets used as an analgesic come in a 300mg strength. The dose is of one to two tablets every four hours if required and no more than 12 tablets in 24-hours.

Aspirin must not be used by anybody that suffers from asthma since it can cause an attack or make one last longer. Asthmatics are extremely sensitive to aspirin and the results could be life threatening.

It should also not be used by anybody that suffers from stomach problems, especially those that have or have had stomach ulcers in the past, since it irritates the lining of the stomach and can cause bleeding. It is recommended to be used with or after food to reduce the chances of a stomach upset.

Aspirin must never be used by anybody under the age of 16 since it can lead to a very serious disease called "Reye’s Syndrome", which is a rare but potentially fatal condition that affects the liver and brain and is most common in children.

If this painkiller must be used on people under that age, make sure that it is only under doctors supervision and with a prescription.

Aspirin is not suitable for pregnant or breast-feeding women or for people that have to use prescribed warfarin since it increases its effect.

- “Junior” Aspirin, is a term used to describe low dose aspirin (75mg). This is used by people who have too much clotting factor in their blood.

It does not actually “thin the blood” like many people believe, but by making the platelets in the blood less sticky, which in turn stops the clotting.

This provides people at risk of heart attack or strokes with protection and prevention.

The dosage for an adult is of one 75mg tablet each day and should only be used for this purposes on the advice of a doctor.

Warning: Aspirin 75 mg is NOT used as a painkiller at all, and especially not in children.

Remember, this is not a child’s dose for pain relief.
This type of aspirin is used as an anticoagulant in adults only.

 - Ibuprofen:
Ibuprofen is also a Non-Steroidal Anti-Inflammatory Drug (NSAID) which is related to aspirin in many ways and basically works in the same manner as aspirin.

It helps reduce inflammation and can help relieve muscle cramps.
It will also help reduce high temperatures in the body.

Ibuprofen is safe to use in children over 6 months of age and can be used as an alternative to paracetamol, if there is inflammation accompanied with the pain.

The dose for children depends on the age and weight of the child:
Children aged 6+ months (over 5kg) can take 60mg/2.5 ml up to three times in 24-hours leaving a minimum of 4 hours gap in between doses.

Children aged 1-3 years can use 120mg/5 ml up to three times in 24-hours with the minimum gap time of four hours.

Children aged 4-6 years old can use 180 mg/7.5 ml up to three times a day every four hours.

Children aged 7-9 years old can take 240 mg/10 ml up to three times a day every four hours.

Children 10-12 years of age can use 360 mg/15 ml up to three times in 24-hours in intervals of four hours gap minimum.

Unfortunately, ibuprofen is not gentle on the stomach either so it should not be used by anybody that has had stomach ulcers in the past since it can cause them or worsen them.

Anybody who suffers from asthma should use this method of pain relief with caution if it was strongly required for inflammation since it can cause an asthma attack or make one last longer; unfortunately just like with aspirin, the results could be life threatening so therefore its use is not recommended in asthmatics unless otherwise advised by a doctor.

Ibuprofen, in comparison to aspirin, is less likely to interact with other medicines and it can be used safely by breast-feeding women. Pregnant women should avoid its use.

Ibuprofen in adults can be obtained in strengths of 200-400 mg tablets.

One to two 200mg tablets can be taken every four hours if needed, but not more than 6 tablets in 24-hours should be used.
Otherwise one 400mg tablet every four hours and not more than 3 tablets in 24-hours.

- Diclofenac:
Diclofenac is also a Non-Steroidal Anti-Inflammatory Drug that also relieves pain and reduces fever.
This is a very useful drug when dealing with conditions such as joint trauma, back pain, acute sports injuries, sprains and osteoarthritis.

Diclofenac is recommended for the short-term relief of pain caused by headaches, dental, rheumatic, muscular, period and back conditions.
It can also be very useful when treating the symptoms of colds and influenza.

Diclofenac is one of a series of phenyl-acetic acid NSAIDs (contains benzene-acetic acid) and can be supplied as either the sodium (Na) or potassium (K) salt.

The potassium salt ones are absorbed faster than the enteric coated ones with sodium salt instead.

Diclofenac works firstly by reducing inflammation, which happens due to the reduction in prostaglandin synthesis via inhibition of the COX-1 and COX-2.

I does not have any direct affect on hyperalgesia (sensitivity of the pain receptors caused by inflammation) or on the pain threshold, but it does have analgesic activity where inflammation is present by inhibition of further production of the prostaglandins that are responsible for sensitising the pain receptors.
The suppression of prostaglandin synthesis, in and near the hypothalamus, is responsible for reducing fever as well.

The doses for adults and children over the age of 14 years is as follows:
Starting with two tablets containing 12.5 mg of the active ingredient, then followed by one to two tablets every four to six hours if required.
Never use more than six tablets (75 mg) in 24-hours time-frame and you must make sure not to used them for longer than three days.

Warning: Diclofenac tablets must never be used by anyone under 14 years of age.

When using diclofenac, always start with the lower dose to try to control the symptoms of pain.
Anyone still suffering from pain after three days of treatment should seek medical advise.

Diclofenac is a well tolerated analgesic, unfortunately, just like with any other NSAID, it is associated with adverse effects on the gastro-intestinal (GI) tract such as bleeding, ulceration and perforation.

In high doses intakes and prolonged treatments, diclofenac has been associated with small increases in the risk of myocardial infarction or strokes.

Warning: If anyone is using any of the following drugs, they should not use diclofenac without doctor’s advise: aspirin or another NSAID, COX-2 inhibitors, diuretics, digoxin, oral hypoglycaemics, anticoagulants, lithium, antihypertensives, corticosteroids, methotrexate, quinolone antibiotics, ciclosporin, tacrolimus or SSRIs.
Caution must be taken by elderly people too.

Diclofenac is not recommended for pregnant or breast-feeding women, anybody that suffers from asthma, diabetes, high cholesterol, high blood pressure, and anybody who is likely to suffer from stroke, liver, heart, kidney or bowel problems.

This analgesic should also be avoided by those who smoke, have intolerances to some sugars (e.g. lactose) or are on controlled potassium diets.

TOPICAL ANALGESICS:

These are analgesics that are applied directly to the skin rather than taken orally.
They act directly on the point of pain whereas oral analgesics will affect the whole body and may not have the strongest effect on the site of pain.

Topical analgesics come in different forms, such as: liquids, sprays, rubs, creams, gels or ointments.

There are two types of topical treatments, some that contain ingredients that masks the pain and others that contain ingredients that will make the area feel either hot or cold to help ease the pain.

Some common ingredients are:

- Non-Steroidal Anti-Inflammatory Drugs (aspirin, ibuprofen, diclofenac, benxydamine, felbinac, ketoprofen and piroxicam):
These active ingredients help reduce swelling and can be very useful when dealing with sprains and strains or any other type of muscular aches and pains.

There is always a risk from any topical analgesics getting into the blood stream from the skin whenever they are applied, so as with any NSAID, if you are asthmatic or allergic to these ingredient, simply do not use them.

They work by inhibiting the cyclo-oxygenase (COX) enzymes and reducing the conversion of arachidonic acid to prostaglandins.

- Nicotinates (e.g. methyl nicotinate):
These ingredients work by opening up the blood vessels under the skin, therefore making the area feel warm. The warmth produced, then, soothes the pain and helps relax any taut, cramping muscles.

- Salicylates (e.g. glycol monosalicylate, methyl salicylate):
These ingredients work by reducing any inflammation and pain.

- Counter irritants (e.g. menthol and camphor):
Ingredients such as these, work by stopping the pain messages that are being sent to the brain via the nerves in the body. Basically they make the brain think that the area is not painful, just the same way that rubbing the affected area with your fingers would work.

- Heparinoids:
These work by reducing swelling and bruising in the area affected.

- Benzydamine:
This ingredient helps reduce inflammation.

Warning: Some people can be allergic to some of these ingredients and may get a rash or some blistering on their skin after using them. If this is the case, discontinue use immediately.

Children must not use topical analgesics either since their skin is too delicate.
Also this type of analgesic should not be applied to broken skin or anywhere near the genital area, mouth or eyes.

NEWS:

- Snail venom:

Apparently the venom used by a Pacific snail to paralyse its prey has been used to develop a new analgesic for some types of chronic pain.

The active ingredient, ziconotide, is 1000 times more powerful than morphine, and is not believed to be addictive.

As it is currently delivered via a pump implanted into the spine, however, an invasive procedure is required.

- Now… which analgesic should you use?:

It has been found in a recent survey, that a worrying number of people do not know the difference between the most common analgesics - yet they continue to take them to relieve whatever type of pain they are suffering from.

The survey, which involved 1112 members of the general public, coincided with last November’s Ask About Medicines week.

The results suggest that one in three people in the UK does not know when it is best to use aspirin, ibuprofen or paracetamol.

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