Painkiller or analgesic is any member of the group of drugs used to achieve analgesia — relief from pain. Analgesic drugs act in various ways on the peripheral and central nervous systems and they are distinct from anesthetics.

Pain killers or analgesic which are NSAIDs (nonsteroidal anti-inflammatory drugs) works on the pathophysiological processes that reduce pain, fever and other signs of inflammation in the body.

Corticosteroids pain killers are usually given for the management of musculoskeletal injuries due to its effect on shutting down inflammation causing processes.

The pain which is triggered by any damaged or sensitive nerves like shingles is usually managed by nerve blockers or anti-depressants. These tablets have the capacity to modulate the perception of pain by central nervous system.

Some pain- killers are used as muscle relaxants to decreases the intensity of pain triggered by the muscles group. This pain killer act as sedative for central nervous system.

Panadol (Paracetamol)

It is one of the popular pain killers available and is mainly used for the management of common headaches and non nerve pains. The effective dose is 2 tablets which can be consumed at least 4 times a day. This dose and dosing regimen is considered safe for adults. There are no common side effects for this medication and this drug can be used for longer time period. However overdose of paracetamol can trigger Paracetamol toxicity and low blood sugar, low blood pH, easy bleeding, and if serious will cause acute liver damage; therefore it is highly recommended not to increase the dosage if the intensity of pain increases.

Ibuprofen

This drug is a type of NSAIDs. It works best on inflammation causing substances in a

same way it is used for treating arthritis or any injury. This drug is not allowed to be used

for longer time periods unless the inflammation doesn’t disappear. If this drug is

consumed for longer time periods, it can lead to serious side effects like bleeding,

stomach upset, heart problems and kidney problems. It is highly advised not to consume

overdose of this drug as it can trigger serious consequences.

Aspirin 

Also known as acetylsalicylic acid , is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-

inflammatory medication. Aspirin also has an antiplatelet effect by inhibiting the production of thromboxane A2, which under normal circumstances binds platelet molecules together to create a patch over damaged walls of blood vessels. Because the platelet patch can become too large and also block blood flow, locally and downstream, aspirin is also used long-term, at low doses, to help prevent heart attacks, strokes, and blood clot formation in people at high risk of developing blood clots.It has also been established that low doses of aspirin may be given immediately after a heart attack to reduce the risk of another heart attack or of the death of cardiac tissue. Aspirin may be effective at preventing certain types of cancer, particularly colorectal cancer. The main side effects of aspirin are gastrointestinal ulcers, stomach bleeding, and ringing in the ears, especially with higher doses. In children and adolescents, aspirin is not recommended for flu-like symptoms or viral illnesses, because of the risk of Reye's syndrome.

Codeine

This drug doesn’t work well alone but can give far better results when used with paracetamol in a single formulation. Over the counter drugs are available under the label of co-codamol (which is paracetamol combined with lower quantity of codeine). Drugs under this category are considered as habit-forming or addictive. The reason behind is these drugs makes a person feel unwell for a short time period when stop consuming. Some of the mild side effects that may be experienced include:

dizziness

lethargy

confusion, difficulty concentrating

euphoria, restlessness

blurred vision

dry mouth

limbs feeling heavy or muscles stiff

sweating

Amitriptyline and Gabapentin

Gabapentin is the drug used for treating epilepsy and amitriptyline medication and is used for treating depression. Both of the drugs are also given to patients for treating pain triggered by damaged or hyper-sensitive nerves which includes sciatica, shingles or nerve pain caused by diabetes. Side effects of both the drugs include dizziness and drowsiness and if serious, polyradiculoneuropathy(a condition in which polyneuropathy and polyradiculopathy occur together. An example is Guillain-

Barré syndrome). So, it is no longer recommended as first line therapy for depression.

Morphine

This drug is considered as powerful and strongest pain killers available. It is advised to reserve the use of this pain killer only in severe pain. These medications are only consumed when prescribed by pain specialist or general physician as the doctor will monitor the progress on dosage potency. These drugs are usually used for long term to administer the pain. The side effect of this drug included Constipation, Hormone imbalance as well as easilt to get addictd.

Oxycodone

It is important to point out that Oxycodone is a potent and addictive opioid analgesic medication. It is synthesized from thebaine. Its name is derived from codeine because the chemical structures are very similar. Oxycodone is one of the most powerful medications for pain control that can be taken orally and it is also used in treatment of moderate to severe chronic pain. If overdose happened, extreme sleepiness breathing problems and small pupils may occur.

Marijuana (Cannabis)

The debate over the use of marijuana for medical purposes has been ongoing for years. Marijuana has been hailed as a prescription for many ills and physicians once used it to stimulate appetite, relieve chronic pain, and treat asthma and migraines. Most common indications for use of Marijuana are:

chronic pain migraines( a common type of headache that may occur with symptoms such as

nausea, vomiting, or sensitivity to light) glaucoma(group of eye conditions that lead to damage to the optic nerve) Multiple sclerosis

The side effect of marijuana will cause increased in heart rate due to the changes in the levels of various neurotransmitters, especially dopamine and norepinephrine. It will also cause dry mouth, reddening of the eyes (congestion of theconjunctival blood vessels), a reduction in intra-ocular pressure, muscle relaxation and a sensation of cold or hot hands and feet.