What is painkiller?

Painkillers or analgesics are drugs designed specifically to relief pain. There are several types of analgesics available either through prescription or over the counter in multiple pharmaceutical dosage forms such as tablet, capsule, liquid, injectable, suppository or transdermal patch. Analgesics include paracetamol (also known as acetaminophen; commonly known as Panadol (brand name) locally), non-steroidal anti-inflammatory drugs (NSAIDs), and opioids.

Different classes of painkiller

Paracetamol is available over the counter and is generally used for fever and mild to moderate pain. It has no demonstrable anti-inflammatory activity and hence, has no effect in relieving the symptoms of joint swelling of arthritis.

NSAIDs is a class of drugs that exhibit anti-inflammatory and reduces fever other than analgesic (relief pain) properties. Ibuprofen, indomethacin, naproxen, diclofenac, aspirin, ketorolac, mefenamic acid, ketoprofen, meloxicam, celecoxib and etoricoxib are amongst the drugs categorized under this class. Differences in anti-inflammatory activity between NSAIDs are small, but there are differences in individuals’ tolerance to these drugs and their response to them. Pain relief starts soon after taking the first dose and a full analgesic effect should normally be obtained within a week, whereas an anti-inflammatory effect may not be achieved for up to 3 weeks.

Opioids are another class of drugs used to relieve moderate to severe pain. Since approximately 1500 BC, pure opium is cultivated from the seedpods of Papaver somniferum (poppy). Opiates, such as heroin, codeine, or morphine, are natural derivatives of these alkaloids. An opioid is the synthetic version of opiate and has the same pharmacological effects as opiate. The examples of opioids include fentanyl, pethidine, dihydrocodeine, oxycodone, methadone, tramadol and etcetera.

Benefit compares to risk

1. Paracetamol

   Like all drugs, there is a potential allergic reaction to analgesics. For paracetamol, most of the reactions are mild such as skin rash, itchiness, shortness of breath, hives and facial swelling. Serious allergic reactions to this drug are rare, but when it happens, early cessation of the causative drug and hospitalization is imperative. Paracetamol is generally safe when used within recommended dosage, severe liver and kidney injury leading to organ transplantation or death may occur when misused or overdose, and this risk is increased with frequent consumption of alcohol.

2. NSAIDs

   NSAIDs are generally effective in the treatment of mild to moderate pain secondary to diseases of the musculoskeletal and joints, for instance gout, rheumatoid arthritis and osteoarthritis. Other uses include but not limited to post-operative pain, menstrual pain and dental pain.

   The allergic reaction for NSAIDs may include skin rash, itchiness, wheezing, hives and facial swelling. NSAIDs has the potential for gastrointestinal bleeding. The risk of bleeding is low for people who use NSAIDs intermittently and goes up for those taking them every day or regularly in high dose. This risk is also increased in those over 65 years of age, people with a history of stomach ulcers, and concurrent therapy of blood thinners and/or corticosteroids, smoking and use of alcohol.

   Some people may be at higher risk for heart and kidney related side effects such as heart attack, hypertension and kidney damage. The risk is increased with increasing dose and duration of use, in people who have pre-existing coronary artery disease, hypertension, diabetes, high cholesterol level, kidney disease and people who have had a stroke. However, the heart related side effect is not applicable to aspirin, the only NSAID to reduce the risks of cardiovascular events in patients who have cardiovascular disease.

3. Opioids

   Opioids are often prescribed for the control of pain in terminal illness or for certain chronic non-cancer pain. It has the important role of managing moderate-to-severe chronic pain that is not controlled with non-pharmacologic therapies and non-opioid analgesics.

   Opioids, when take in low doses are safe and effective but deadly when overdosed or not taken as directed by physician. Nausea, vomiting, constipation, euphoria (a state of intense happiness, and self-confidence), mood changes, rashes, drowsiness are among the common side effects.

   Chronic use of opioid analgesics is associated with the development of dependence and tolerance. When the body develops dependence, it means that it begins to rely on opioids and abrupt stopping of the drug will cause withdrawal symptoms such as shivering, nausea, sweating and irritability. Tolerance characterised the need of higher amount of opioids over time to achieve the same amount of pain relief effects. Dependence is a natural response of the body to opioids, it doesn’t mean the same as addiction. Addiction is characterised by behaviour such as impaired control of drug use, compulsive use (performing an act persistently and repetitively), continued use despite harm and craving. This often leads to cases of fatal overdose where patient may stop breathing, has decreased level of consciousness, seizure and having abnormal heart rhythm.

Advice to consumers

• Stop taking the drug immediately once you experience side effects and seek advice/treatment from healthcare professionals.
• Before starting an analgesic, information such as concurrent medication and presence of any disease are important to healthcare professionals in choosing the suitable choice of analgesic to prescribe.
• Any doubts or questions pertaining to the analgesics should be addressed to healthcare professionals.
• Do not change the dose of the analgesic without first consult with your physician and do not share the analgesics you are taking with anybody because it might not be safe for the person.

1. Paracetamol

   Taking higher doses than recommended of paracetamol will not provide more pain relief and can lead to severe liver and kidney damage. The maximum dose for adult is 4g in 24 hours and is lesser in children. Always refer to the product label and follow the instruction given exactly as stated.

   Combination products containing paracetamol as one of the active ingredients is also available. To minimize the risks of an accidental overdose, consumers should avoid taking multiple medications with the same active ingredient at the same time.

   Consuming ? 3 alcoholic drinks per day may increase the risk of liver damage.

2. NSAIDs

   Aside from the risks mention above, cross-reaction exists between drugs categorised under NSAIDs. It means that if a person is allergic to one of NSAIDs medication, he/she might be allergic to other type of NSAIDs as well.

   The prevalence of NSAID-induced asthma or worsening of asthma in patients with underlying asthma is higher than that of general population, hence people with asthma should take caution on the consumption of this class of medication.

   Avoid taking multiple NSAIDs at the same time as it increases the risk of stomach bleeding and always take them after food for the same reason.

3. Opioid

   Avoid driving or using any machinery that may cause injury after taking opioids as they can lead to drowsiness and euphoria. Do not take opioids together with alcohol, antihistamines, or drugs that also causing drowsiness. These substances slow breathing and their combination could lead to life-threatening respiratory depression.

   Before starting on opioid, your Healthcare professionals should be informed of any past history of substance abuse.

   Opioid addiction is rare when the drug is prescribed for therapeutic use. In this case the increment of dosage more often means disease progression or development of tolerance, and not addiction.

   Consumers should always take opioid as exactly as prescribed by physician. It is very important not to crush a sustain-released tablet before taking it as it can cause overdose.