Monday, June 25, 2012

What Are NSAIDs (Non-Steroidal Anti-Inflammatory Drugs)? What Are NSAIDs Used For?

NSAIDs are non-steroidal anti-inflammatory drugs, also known as NAIDs, non-steroidal anti-inflammatory agents/analgesics (NSAIAs) or non-steroidal anti-inflammatory medicines (NSAIMs). They are medications with analgesic (pain reducing), antipyretic (fever reducing) effects. In higher doses they also have anti-inflammatory effects - they reduce inflammation (swelling). Non-steroidal distinguishes NSAIDs from other drugs which contain steroids, which are also anti-inflammatory. NSAIDs are non-narcotic (they do not induce stupor).

The most common NSAIDs are aspirin, ibuprofen and naproxen - probably because they are available over-the-counter (OTC, no prescription required).

NSAIDs can be used for a number of conditions. While some OTC medications, others can only be accessed with a prescription. Typically, NSAIDs are used to treat the following symptoms and conditions:
  • Pain and discomfort - for example muscle strain/sprain, headaches, migraines, and dysmenorrhea (painful cramps during menstruation).
  • Fever - NSAIDs are effective at reducing body temperature.
  • Inflammation - NSAIDs are often used for the treatment of inflammation, as may occur in rheumatoid arthritis.
  • Some other conditions - sometimes NSAIDs are recommended for the treatment of menorrhagia (heavy menstrual periods).
NSAIDs may be taken:
  • Orally (by mouth) - available in tablet, capsule or liquid form.
  • Intravenously - by injection
  • Rectally - as a suppository through the rectum
  • They are also available as eye-drops
  • Topical NSAIDs also exist, which are applied directly onto the skin in the form of creams or gels.
According to Medilexicon's medical dictionary:

Nonsteroidal antiinflammatory drugs (NSAIDs) are "a large number of drugs exerting antiinflammatory (and also usually analgesic and antipyretic) actions; examples include aspirin, acetaminophen, diclofenac, indomethacin, ketorolac, ibuprofen, and naproxen. A contrast is made with steroidal compounds (hydrocortisone or prednisone) exerting antiinflammatory activity."

Types of NSAIDS

NSAIDs are based on their chemical structure:
  • Propionic acid derivatives - Examples include: Ibuprofen, Naproxen, Fenoprofen, Ketoprofen, Flurbiprofen, Oxaprozin

  • Acetic acid derivatives - Examples include: Indomethacin, Sulindac, Etodolac, Diclofenac (Safety alert by FDA)
  • Enolic acid (Oxicam) derivatives - Examples include: Piroxicam, Meloxicam, Tenoxicam, Droxicam, Lornoxicam, Isoxicam
  • Fenamic acid derivatives - Examples include: Mefenamic acid, Meclofenamic acid, Flufenamic acid, Tolfenamic acid
  • Selective COX-2 inhibitors (Coxibs) - Examples include: Celecoxib (FDA alert), Rofecoxib (withdrawn from market), Valdecoxib (withdrawn from market), Parecoxib (FDA withdrawn), Lumiracoxib (TGA cancelled registration), Etoricoxib (FDA withdrawn)

How do NSAIDs work?

Initially, scientists who first developed NSAIDs were not sure how they worked. However, subsequent research has given the scientific community a much better understand of them.

Enzymes - these are protein-based molecules that either trigger or speed up specific chemical reactions in the body, and convert substrates (specific set of reactants) into specific products. For example, digestive enzymes help the digestive system break up large food particles into smaller ones so that the body can absorb them. Without enzymes life as we know it would not exist.

NSAIDs interfere with cyclo-oxyganase (COX), a type of enzyme. Different types of COX enzymes exist in various parts of the human body - they control the production of prostaglandins, which have different functions. COX-1 enzymes exist in the stomach and control the production of prostaglandins which protects the stomach from acid. COX-2 enzymes exist in white blood cells, which control the prostaglandins involved in pain and inflammation.

Prostaglandins - these are hormone-like substances that participate in a wide range of body functions, one of which causes pain and inflammation. NSAIDs prevent the COX enzymes from releasing the prostaglandin chemicals responsible for inflammation and pain. However, prostaglandins have other vital functions, such as protecting the stomach from indigestion and ulcers, so NSAIDs can have undesirable side effects.

COX-2 inhibitors - these are newer NSAIDs. While the COX-1 enzyme protects the stomach, COX-2 enzymes cause inflammation and pain in the body. Until COX-2 inhibitors arrived, NSAIDs inhibited both COX-1 and COX-2 enzymes - while helping with pain and inflammation; they would also make the stomach more vulnerable to damage.

Specific COX-2 inhibitor - NSAID medications were created that inhibited the COX-2 enzyme, but not the COX-1 ones. The aim was to relieve pain and inflammation without causing side effects for the stomach. However, COX-2 inhibitors, while not damaging the stomach, do cause more side effects for the heart compared to the old NSAIDs. So specific Cox-2 inhibitor NSAID medications are suitable for patients who are more likely to develop intestinal and/or stomach problems, but unsuitable for those with circulation or heart problems.

Factors to consider

Some patients may be more at risk of developing side effects after taking NSAIDs than others. In fact, there are possible side effects for anybody who takes them.

Stomach and intestinal side-effects (gastrointestinal side effects) - NSAIDs can cause such gastrointestinal problems as stomach ulcers or indigestion. The following groups of people may be at higher risk of developing gastrointestinal problems when taking NSAIDs:
  • Elderly individuals (aged over 65 years)
  • Heavy smokers
  • Patients who are taking other medications at the same time
  • Patients who have a history of gastrointestinal problems
  • Patients who take NSAIDs in high doses
  • Patients who take NSAIDs long-term
  • Patients with some other conditions, such as hypertension, cardiovascular disease, or diabetes
Cardiovascular and kidney side effects - in some cases, NSAIDs may raise the risk of problems for the kidneys, heart or blood vessels. The following groups of people have a higher risk of these types of side effects when taking NSAIDs:
  • Elderly patients (aged over 65 years)
  • Patients with hypertension (high blood pressure)
  • People with faulty/damaged hearts or kidneys
  • People with kidney or heart failure
Pregnancy - women who are pregnant, and those planning to become pregnant should avoid NSAIDs. There is a health risk to both the mother and the baby. During the first and second trimesters of pregnancy, taking NSAIDs poses a very small risk for the baby's health; during the third trimester there is a risk the baby may develop pulmonary hypertension (arteries in the lungs become narrowed, causing hypertension and some other problems).

Fertility - some people may find it harder to conceive when taking NSAIDs. Experts advise such people to use other painkillers, such as acetimophen (Tylenol, paracetamol) if they are trying to have a baby.

Giving birth - a mother who takes NSAIDs shortly before giving birth may find the labor process takes longer.

Breastfeeding - breastfeeding mothers should avoid NSAIDs while breastfeeding, even though the risk to the child is very small, says the National Health Service (NHS), UK. The NHS adds that if an NSAID is prescribed to a nursing mother, it is usually a very low dose.

Asthma - there is a risk symptoms may worsen if asthma patients take NSAIDs. It is recommended that asthma patients try to avoid them. In some cases, doctors may prescribe an NSAID for asthma patients if they are deemed to be beneficial; in such cases it will be a short course of medication.

Post-surgery bleeding - there is a risk of excessive bleeding after surgery or a traumatic injury if the patient takes NSAIDs.

Long-term NSAIDs - patients on long-term NSAID therapy should be monitored carefully.

What are the possible NSAID side effects?

A large percentage of patients take NSAIDs and experience no side effects. NSAIDs are very effective for a wide range of conditions. Patients and health care professionals must not forget, however, that most drugs carry a risk of some side effects. Although rare, NSAID side effects may be serious.

The most common NSAID side effects include:

Long-term use -
  • Dyspepsia - also known as indigestion or upset stomach; a term that describes discomfort or pain in the upper abdomen. It is not a disease. Dyspepsia is a group of symptoms which often include bloating, nausea and burping.
  • Stomach ulcers - these may eventually result in the following complications:

    A hole in the wall of the stomach or intestines (gastrointestinal perforation)

    Anemia - when the number of red blood cells or concentrations of hemoglobin are low a person is said to have anemia. Hemoglobin is a protein (metalloprotein) inside the red blood cells that contains iron and transports oxygen.

    Gastrointestinal bleeding
The following less common side effects are also possible, and tend to only affect patients with an existing cardiovascular condition:
  • Heart attack - if the heart muscle does not have enough blood (and consequently oxygen) it dies and a heart attack occurs.
  • Heart failure - a serious condition in which the heart is not pumping blood around the body efficiently. The patient's left side, right side, or even both sides of the body can be affected.
  • Hypertension - or high blood pressure is a condition in which the blood pressure in the arteries is chronically elevated.
Liver and kidneys - in very rare cases, and then only in patients with existing liver or kidney conditions, the medication may affect the liver or kidneys.

NSAID interactions with other medications or alcohol

In some cases, a combination of an NSAID with certain medications or alcohol may cause undesirable side effects.

NSAID interactions with certain medications - if a patient is taking an NSAID together with any of the medications below, they should be monitored closely in case an undesirable side effects develop (some in the list below should never be taken alongside NSAIDs):
  • Ciclosporin - an immunosuppressant medication taken by organ transplant recipients so that their bodies do not reject the new organ.
  • Clozapine - an antipsychotic drug used in the treatment of schizophrenia.
  • Lithium - a mood stabilizer for the treatment of bipolar disorder.
  • Methotrexate - used to treat diseases associated with abnormally rapid cell growth such as certain tumors and psoriasis. Also used for the treatments of rheumatoid arthritis.
  • Phenytoin - an anticonvulsant used in the treatment of epilepsy.
  • Quinolones - synthetic antibiotics that inhibit the replication of bacterial DNA.
  • Some diuretics - products that promote the formation of urine by the kidney; they increase the amount of water the body gets rid of.
  • SSRIs (selective serotonin reuptake inhibitors) - medications commonly prescribed for the treatment of depression.
  • Sulphonylurea - medication that raises the secretion of insulin by the pancreas. Prescribed for patients with Type 2 Diabetes to lower blood glucose levels.
  • Warfarin - a blood thinner used to prevent blood clots.
NSAID interactions with alcohol - in most cases a man can consume 3 to 4 units of alcohol per day, and a woman 2 to 3 units per day, while taking ibuprofen or aspirin. If alcohol is consumed in higher amounts, while taking aspirin or ibuprofen there is a risk of irritation to the stomach lining.

Heavy drinkers who take ibuprofen or aspirin have a higher risk of bleeding in the stomach.

Some more powerful prescription NSAIDs should not be taken with alcohol.

Not all NSAIDs are the same. In each case the patient should read the information leaflet that comes with the product carefully, or consult with a qualified pharmacist or their doctor.

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