Painkillers: 3 Main Types, Uses, And Side-Effects

There are three main types of

painkillers

: non-steroidal anti-inflammatory drugs (**NSAIDs**),

paracetamol

, and

opioids

. Each works in a different way to provide relief from various types of pain. Most people only need painkillers for a few days or weeks, but some require longer-term use under medical supervision.

Some painkillers are available over-the-counter (OTC) from pharmacies, including certain NSAIDs like ibuprofen, paracetamol, and weak opioids such as codeine or dihydrocodeine. Stronger options often require a prescription. Combinations like paracetamol plus codeine (co-codamol) are common for enhanced effect.

In addition to these, antidepressants and antiepileptic medicines can treat neuropathic (nerve-related) pain, though this article focuses on standard painkillers. Alternative methods like transcutaneous electrical nerve stimulation (TENS) machines or ice/heat therapy may complement pharmacological approaches.

Non-steroidal anti-inflammatory drugs (NSAIDs)

**NSAIDs** reduce pain, fever, and inflammation by blocking cyclooxygenase (COX) enzymes, which produce prostaglandins—chemicals that promote inflammation, pain, and fever. There are two main types: COX-1 and COX-2. Non-selective NSAIDs (e.g., ibuprofen, diclofenac, naproxen) block both, while selective COX-2 inhibitors (e.g., celecoxib) target mainly COX-2 to minimize stomach side effects.

Common NSAIDs include aceclofenac, acemetacin, aspirin, celecoxib, dexibuprofen, dexketoprofen, diclofenac, etodolac, etoricoxib, fenoprofen, flurbiprofen, ibuprofen, indometacin, ketoprofen, mefenamic acid, meloxicam, nabumetone, naproxen, sulindac, tenoxicam, and tiaprofenic acid.

NSAIDs are effective for joint pain, post-operative pain, sprains, arthritis, and painful periods. A single dose works as well as paracetamol for mild pain, but repeated doses reduce inflammation over 1-3 weeks, easing stiffness in conditions like rheumatoid arthritis.

• Uses as painkillers: Relieve acute pain from injuries, surgery, or musculoskeletal issues.
• Anti-inflammatory effects: Best for conditions with swelling, such as osteoarthritis or gout.

Most people tolerate NSAIDs well, but caution is advised for those with cardiovascular disease, gut issues (e.g., ulcers), or the elderly. Use the lowest effective dose for the shortest time.

Paracetamol

**Paracetamol** (also known as acetaminophen) is a widely used painkiller and fever reducer. Its exact mechanism is unclear but likely involves blocking COX enzymes in the brain and spinal cord (central nervous system), without significant anti-inflammatory effects.

It treats headaches, muscle aches, toothache, colds, flu, and high temperatures but does not help with inflammation-related pain like sprains. Available OTC in tablets, liquids, or suppositories, it’s safe for most people when taken as directed. Overdose can cause severe liver damage, so never exceed 4g daily (or less if combined with other drugs).

Weak opioids

**Weak opioids**, like codeine or dihydrocodeine, are prescribed for moderate pain when paracetamol or NSAIDs fail. They bind to opioid receptors in the brain and spinal cord, reducing pain perception.

Codeine is common for mild-to-moderate pain, often combined with paracetamol. Side effects include nausea, constipation, drowsiness, and dry mouth. It’s available OTC in low doses but requires prescription for higher strengths. Dihydrocodeine works similarly.

These are a step up from non-opioids but carry risks of dependence with prolonged use.

Stronger opioids

**Strong opioids** treat severe pain, such as cancer pain, post-surgery, or major injuries. Examples include morphine, oxycodone, diamorphine, tramadol, and fentanyl patches[10].

They act on the central nervous system to significantly alter pain signals. Common side effects: constipation, nausea, tiredness, and sedation. Long-term use risks dependence and addiction; recent guidelines caution against routine long-term prescribing due to limited benefits and high addiction risk. Short-term use, especially in end-of-life care, is often effective without addiction.

• Morphine: Often started with immediate-release for breakthrough pain plus slow-release for steady control.
• Oxycodone: Used post-surgery or for cancer pain; available as capsules, tablets, liquid, or injections.
• Diamorphine: Strong opioid for severe pain, particularly post-op or cancer-related[10].

Prescribed only when weaker options fail, with careful monitoring.

Topical painkillers

**Topical anti-inflammatory painkillers** (creams, gels, sprays, patches) target localized soft tissue, muscle, or joint pain with fewer systemic side effects. They contain ibuprofen, diclofenac, felbinac, ketoprofen, or piroxicam.

Ideal for sprains, strains, arthritis, or sports injuries. Capsaicin creams offer alternative relief from other substances. Apply to clean skin, avoiding broken areas or eyes. Wash hands after use.

These are safer for those unable to take oral NSAIDs due to stomach risks.

Other painkillers

For

chronic pain

, options expand to non-opioid orals like muscle relaxants (tizanidine, cyclobenzaprine, baclofen), COX inhibitors, and antidepressants (tricyclics, SNRIs) that block nerve pain at low doses. Neuropathic pain may require antiepileptics.

Which painkillers to use?

Choice depends on pain type, severity, and cause:

Pain Type	Recommended Painkillers
Mild pain (headache, toothache)	Paracetamol or NSAIDs
Inflammatory pain (arthritis, sprains)	NSAIDs (oral or topical)
Moderate pain	Weak opioids + paracetamol/NSAID
Severe pain (cancer, post-op)	Strong opioids
Nerve pain	Antidepressants/antiepileptics

Start with the weakest effective option. Combine if needed (e.g., paracetamol + codeine). Consult a doctor for persistent pain.

Painkillers when pregnant

Use caution during pregnancy. Paracetamol is generally safest. Avoid NSAIDs after 30 weeks due to fetal risks (heart/lung issues). Weak opioids may be used short-term if benefits outweigh risks; strong opioids avoided. Always seek medical advice.

Side-effects of painkillers

• NSAIDs: Stomach upset, ulcers, bleeding, kidney issues, heart risks (higher doses/long-term).
• Paracetamol: Liver damage (overdose).
• Opioids: Constipation, nausea, drowsiness, dependence, respiratory depression.
• Topical: Skin irritation (rare systemic effects).

Take with food/milk for NSAIDs; laxatives for opioid constipation.

Who should not take painkillers?

Avoid or use cautiously if you have:

• Stomach ulcers/bleeding (NSAIDs).
• Liver/kidney disease (adjust doses).
• Heart conditions (NSAIDs).
• Breathing issues/addiction history (opioids).
• Pregnancy/breastfeeding (consult doctor).

Children/asthma patients need tailored advice.

How to take painkillers

Follow dosage instructions precisely. For chronic pain, regular scheduling beats ‘as needed.’ Track intake to avoid overdose, especially paracetamol combos. Inform doctors of all medications.

Frequently Asked Questions (FAQs)

What is the safest painkiller?

Paracetamol is often safest for mild pain and fever, with low side-effect risk when dosed correctly.

Can I take ibuprofen and paracetamol together?

Yes, alternating or combining is common for better relief, but respect maximum daily limits.

Are opioids addictive?

Yes, especially long-term; short-term use under supervision minimizes risk.

When should I see a doctor for pain?

If pain persists >1 week, worsens, or accompanies fever, swelling, or neurological symptoms.

Do topical painkillers work?

Yes, effectively for localized muscle/joint pain with minimal systemic absorption.