What is an Analgesic?

Analgesics are medications to relieve pain and hence, are also known as painkillers. They either reduce inflammation at the site of pain or change the way our brain processes and perceives pain. Some types of analgesics are easily available over-the-counter, but stronger variants need a prescription. Strong analgesics may cause side effects and hence, should be taken in the right dosage as suggested by the healthcare provider.

Analgesics are pain relievers but do not act like medications used for anaesthesia during surgery. Analgesics don't turn off your nerves or alter consciousness, but they relieve pain and inflammation. Generally, analgesics are used as painkillers after surgery, for acute pain like twisted ankle or headache, for chronic pains like back pain, arthritis or cancer and for pain due to fractured bones.

In this article, let us understand different types of analgesics, how an analgesic works, its side effects and some necessary precautions before taking an analgesic.

Types of Analgesics

There are two main groups of analgesics anti-inflammatory analgesics and opioids. Additionally, there are also Non-steroidal anti-inflammatory drugs (NSAIDs) which reduce pain and swelling by blocking the effects of chemicals like prostaglandins in our body.

  • Anti-inflammatory Analgesics − These medications reduce swelling at the site of the pain and act as a pain reliever. Some examples of these drugs include acetaminophen, aspirin, COX inhibitors and NSAIDs like ibuprofen and naproxen.

  • Opioids − Analgesic opioids which are also known as narcotics change the brain's perception of pain. They reduce the pain signals sent by the nervous system and thereby control the brain's reaction to the pain. Some examples of opioids include Avinza, Kadian, or MS Contin (morphine), Oxycontin (oxycodone), Dolophine or Methadose (methadone), Dilaudid (hydromorphone), codeine, Demerol (meperidine), Duragesic and Actiq (fentanyl).

These analgesics are available in many forms such as pills, tablets or capsules which you can easily swallow. Other forms of analgesics include powder form, nasal spray, gels, patches and liquid that can be injected with a syringe or a liquid that can be swallowed. You can seek guidance from your healthcare provider about which form can be suitable for you.

How Do Analgesics Work?

Analgesics are taken to alleviate many types of pain including postsurgical pain, menstrual pain, headache, toothache, burns, bites or stings etc. Doctors may recommend an analgesic like acetaminophen and an NSAID before recommending an opioid analgesic. Alternatively, different analgesics work in a different manners and your doctor may prescribe an analgesic as per your requirement. NSAIDs are used to reduce inflammation at the site of pain, while opioids reduce neuronal activity.

Opioids dull your pain perception and are generally beneficial for short-term pain. Over time, you may experience that an analgesic can become less effective as the body becomes tolerant to it. In such cases, you may require higher doses or more frequent doses of an analgesic. Do not experiment on your own and seek medical attention if you feel that your pain reliever medications are unable to reduce your pain.

Side Effects of Analgesics

Anti-inflammatory analgesics are usually safe, but they may cause certain side effects if you use them frequently or take them in large doses. Similarly, opioid analgesics can cause many side effects and health complications if their doses and frequency are not controlled.

People can also develop addiction and substance use disorder if opioid analgesics are not taken as per the prescribed doses. The possible signs of substance use disorder are −

  • Taking analgesics in larger quantities

  • Being unable to cut down on usage. This is also called dependence.

  • Taking medications in situations like driving

The side-effects of analgesics can be categorised as per their severity ranging from mild to severe. The less serious side effects of analgesics can be −

  • Diarrhoea

  • Nausea

  • Constipation

  • Indigestion

  • Vomiting

  • Headache

  • Dizziness

  • Drowsiness

  • Heartburn

Some of the serious side-effects of analgesics are as follows −

  • Allergic reactions like a skin rash

  • Chest pain

  • Stomach Ulcer

  • Liver or kidney damage

  • Light sensitivity

  • Trouble breathing

Some of the possible side-effects of opioid analgesics can be −

  • Itching

  • Low sex drive

  • Difficulty in concentration

  • Problem with urinating or passing stools

  • Erectile dysfunction

  • Reduced capacity to fight infections

  • Reduced fertility

Precautions with Analgesics

Analgesics if not taken in adequate doses can cause side effects and hence, they should be taken in a controlled manner. You should discuss your health condition with your doctor in detail so that the doctor can decide the exact dose of analgesic for you. Alcohol can worsen the side effects of analgesics and hence, people who are on analgesics are advised to avoid alcohol. Additionally, if you are pregnant, are breastfeeding or are thinking of conceiving, discuss with your doctor before taking an analgesic.

Some NSAIDs may increase the risk of stomach bleeding, heart attack and stroke. If you are a heart patient, you must discuss the risk factors before taking an analgesic. When you start taking an opioid, you should avoid performing tasks that require alertness like driving. Moreover, tell your doctor about any prescription, over-the-counter, herbal, dietary, nutritional or recreational medications you are taking before starting on an analgesic.

When to Consult a Doctor for Analgesic Side Effects?

You must seek immediate medical attention if you are on an analgesic and experience any of the following −

  • Severe allergic reactions like skin rash or swelling

  • Black stools or poop

  • Blood in vomit

  • Change in vision

  • Difficulty or change in hearing

  • Severe abdominal pain or headache

  • Cloudy or discoloured urine or trouble urinating

  • Jaundice where your eyes or skin turn yellowish

  • Sudden weight gain


Analgesics can be effective painkillers or pain relievers only if they are taken in the right doses. They can help to reduce inflammation or change the way the brain can perceive pain.

Analgesics are available in many forms like tablets, pills, powder, nasal spray, liquids, gels and patches. Some of them are easily available as over-the-counter medications, but some may require a prescription from your doctor. Always discuss your health condition, medical history and medications with your healthcare provider. This can help your provider to figure out the perfect type of analgesic and decide the right dose for you.