Drugs:

The use of drugs has been the most important advance in the control of pain over the last century or so. Before 1900 aspirin and simple derivatives of opium (similar to morphine) were the only analgesic drugs available, but now there are many more. Although the price of a growing use of drugs has been an increase in side-effects, in general these risks are far outweighed by the benefits. Nevertheless, the balance of benefit and risk should always be considered.

One thing to bear in mind about drugs is that they may be available under several different names. Each drug will have an approved (or generic) name but manufacturers often give their own brand or trade name to the drug as well – for example, diclofenac is an approved name; Voltarol is a trade name for diclofenac made by Novartis, and Diclomax is a trade name for diclofenac made by Provalis. This can be very confusing. The approved name should always be on the pharmacist's label even if a trade name appears on the packaging, but check with your doctor, nurse or pharmacist if you are in any doubt. We will use the approved names in the sections which follow.

Pain-killing (analgesic) drugs:

Drugs which act specifically against pain are called analgesics. They include simple analgesics such as paracetamol.

PARACETAMOL

The simplest of painkilling medication is Paracetamol.

It can be taken by those with peptic ulcers, and those who are sensitive to aspirin.

When taken at the recommended dosage, there are virtually no side-effects.

Paracetamol does not reduce inflammation but it now appears to have a highly targeted action in the brain, blocking an enzyme involved in the transmission of pain.

Paracetamol can be taken in addition to anti-inflammatory agents.

Dosage

The recommended adult dose of paracetamol is two 500 mg tablets, with four hours between doses, and no more than eight tablets in 24 hours.

If this recommended dose is adhered to, there will be no toxic effects, even in prolonged or habitual use. Paracetamol does not accumulate in the body following normal doses. It is not absorbed any more rapidly or slowly than other highly popular pain relieving medicines and does not leave the stomach at a different rate.

In substantial overdose liver damage is likely to occur assuming the patient does not receive treatment.

More complex analgesic drugs are related chemically to morphine, but with a much lower risk of developing dependency. These include codeine, dextropropoxyphene and dihydrocodeine. These are often used more effectively in combination with paracetamol, and are made as compound tablets – e.g. paracetamol and codeine (co-codamol) or paracetamol and dihydrocodeine (co-dydramol). These compounds often cause constipation and may produce drowsiness, especially if taken with alcohol. They may, however, be very helpful for most types of pain. Stronger drugs, including slow-release morphine or patches containing fentanyl or buprenorphine, are necessary in some people with severe pain but these are used with caution.

Non-steroidal anti-inflammatory drugs (NSAIDs):

These combine pain-relieving effects with an additional action which reduces inflammation. As inflammation is the main cause of pain in many conditions – including most forms of arthritis – these drugs can be doubly effective. Their development has been a major breakthrough in the care of people with arthritis, spinal pain and other chronically painful conditions. They are also used for painful periods, headaches and kidney pain. They can be used in combination with the simple or compound analgesics mentioned above. They can be helpful even when there is not a great deal of inflammation as, for example, in osteoarthritis.

Ibuprofen is an NSAID which is available over the counter without prescription, reflecting its good safety record, although it can sometimes cause indigestion and ulcers even when it is taken with food. Other commonly available NSAIDs include diclofenac, naproxen and indometacin.

A new type of NSAID is also available. They are called COX-2-specific NSAIDs because they act to block the enzyme COX-2 which is important in the production of the chemicals which cause pain (prostaglandins). Other prostaglandins produced by COX-1 are less important in producing pain but help to protect the stomach from developing ulcers. Blocking COX-2 specifically offers the opportunity to control pain but with a lower risk of producing indigestion and stomach ulcers. COX-2-specific NSAIDs are used particularly in people who are at risk of serious stomach problems – the elderly, those with a past history of peptic ulcers, or heavy smokers or drinkers. However, they are not risk-free. They may, for example, increase the risk of heart attack or stroke, so they are not suitable for people who have had either in the past, or for people who have high blood pressure which is not controlled by medication.

As has already been mentioned, indigestion and inflammation of the stomach are relatively common side-effects from NSAIDs including aspirin. Aspirin should not therefore be taken at the same time as other NSAIDs unless your doctor feels this is necessary. Surprisingly NSAIDs can make some people constipated while others develop diarrhoea. A peptic ulcer is a rarer but more serious side-effect. Anyone who has had severe indigestion or peptic ulcers in the past should avoid using NSAIDs. If the COX-2-specific NSAIDs are suitable for you, your doctor may prescribe one of these instead.

All NSAIDs can sometimes make asthma worse, and other possible side-effects include skin rashes, headaches, muzziness and dizziness. People with kidney problems or who take high doses of diuretic ('water') tablets should be especially careful. Elderly people are often more prone to side-effects from most drugs and they must therefore use NSAIDs with caution.

NSAID gels which are applied to the skin around painful joints help some people and are safe as long as not too much is applied at any one time. These may some-times produce local skin irritation.