Generics

What is AIDS?

Human Immunodeficiency Virus (HIV) is an RNA virus (known as a retrovirus) that specifically attacks the immune system, which affects your ability to fight other infections.  HIV infects CD4 cells, which are white blood cells that play an essential role in the immune response to infection.  Without treatment, the virus multiplies and spreads, and the amount of virus in your body increases, while at the same time, the number of CD4 cells decreases.  Eventually, the immune system becomes severely damaged and is unable to fight infection, leading to an increased risk of opportunistic infection, which is an infection that the body usually can fight when not immunocompromised.  This stage of HIV infection is called Acquired Immune Deficiency Syndrome (AIDS) and is potentially life-threatening. 

How do antiretrovirals work?

Antiretrovirals are used to treat HIV infection, and are designed to prevent the replication of the virus.  The aim of antiretroviral treatment is to reduce the amount of virus in the body (viral load) down to a low level and prevent the spread of HIV.  Antiretrovirals do not kill the virus.  Once HIV replication is reduced, the numbers of CD4 cells can increase, so that the immune system can recover, and further damage is prevented.  Antiretroviral therapy uses a combination of different drugs that work by attacking a different stage of the viral replication process.  Using a combination of drugs reduces the risk of the virus becoming resistant.  Some of these combination medications are supplied as a single tablet containing a fixed dose of two or three drugs.

Types of antiretroviral drugs include:

• Reverse transcriptase (RT) inhibitors.  RT is a virus-specific enzyme needed for HIV replication.  There are two types of RT inhibitor that work by different mechanisms:
  • nucleoside analogue reverse transcriptase inhibitor (NRTI), such as tenofovir and zidovudine
  • non-nucleoside reverse transcriptase inhibitor (NNRTI), such as efavirenz and nevirapine. 
• The viral protease enzyme is another drug target.  This enzyme is needed to allow the mature active virus to be released and infect new cells.  These drugs include ritonavir and indinavir.

What is depression?

Depression is not just feeling low, which we all feel from time to time.  It is a long term feeling of sadness that persists for more than a few weeks and affects your behaviour and quality of life.  Depression is an illness, which can range from mild to severe depending on your symptoms.  These symptoms include anxiety, loss of interest in your usual activities, disturbed sleep, change in appetite, fatigue, feelings of worthlessness or guilt, difficulty thinking or concentrating, and recurrent thoughts of suicide.  This condition is also called Major Depressive Disorder and is one of several mood disorder treated by antidepressants.  Other mood disorders include anxiety disorder, bipolar disorder, obsessive-compulsive disorder (OCD), panic disorder and post-traumatic stress disorder (PTSD).

Depression and other mood disorders are thought to be due to an imbalance of brain chemicals called neurotransmitters, particularly serotonin and noradrenaline.  These brain chemicals pass messages between nerve cells (neurones) in the area of the brain that regulates mood.  When a neurotransmitter is released by one neurone, it passes across the gap between neurones (synapse) and triggers an electrical impulse in the next neurone.  Transmission of a nerve signal from one neurone to another allows nerve cells to communicate with each other.  Any neurotransmitter remaining in the synapse after release from the first nerve cell (pre-synaptic) and not used by the receiving nerve cell (post-synaptic), is taken up back into the pre-synaptic neurone.  This process is called neurotransmitter reuptake.

How do antidepressants work?

Antidepressants are medications that are used to treat symptoms of depression and other mood disorders.  They are classed according to how they work and which brain chemicals they target.  These include:

• Selective serotonin reuptake inhibitors (SSRI) such as fluoxetine, escitalopram, and sertraline.
• Serotonin noradrenaline reuptake inhibitors (SNRI) such as venlafaxine.
• Tricyclic antidepressants, such as imipramine, and tetracyclic antidepressants such as trazodone, are non-selective neurotransmitter reuptake inhibitors as well as blocking effect of other neurotransmitters like histamine and acetylcholine.

Why is high cholesterol a health problem?

Cholesterol is a fat that is produced by the liver but also comes from our diet.  We all need some cholesterol for normal body functions, such as making cell membranes, producing and transporting hormones, and building protective nerve sheaths.  Eating a lot of fatty foods in your diet can increase your blood cholesterol levels above healthy levels.  Since cholesterol is not water-soluble, it circulates in the blood attached to proteins called lipoproteins.  Excess cholesterol is deposited in the arteries causing them to become blocked and hardened, which narrows the arteries and restricts blood flow.  This condition, called atherosclerosis, increases your risk of developing cardiovascular disease, including heart attack, angina, and stroke.

How do cholesterol-lowering medications work?

Cholesterol-lowering medications are used to reduce high cholesterol and triglyceride levels.  They are classed according to how they work and include:

• Statins that block the production of cholesterol by the liver but have no effect on dietary cholesterol, such as atorvastatin, simvastatin, and rosuvastatin
• Cholesterol absorption inhibitors that block the absorption of cholesterol in the intestines, such as ezetimibe
• Fibrates that regulate the amount of lipoprotein produced to carry cholesterol in the blood, such as fenofibrate

What is diabetes?

Diabetes is a condition where blood sugar levels (glucose) are too high and difficult to control.  Insulin, produced by the pancreas, is the main blood glucose regulating hormone.  It ensures that there is enough glucose needed for energy throughout the body, particularly the brain.  Glucose is produced in the liver and also absorbed from the diet.  Excess glucose is stored in the liver and muscles.  Hyperglycaemia is when too much glucose circulates in the blood, either because your body does not make enough insulin or has become resistant to the effects of insulin. 

Diabetes exists in two forms. Type 1 diabetes is usually hereditary, develops early in life, and is caused by damage to the pancreas due to attack by the body’s immune system.  Type 2 diabetes usually begins later in life and is related to lifestyle factors, including obesity, poor diet, smoking, and lack of exercise.

Diabetes increases the risk of serious health complications caused by damage to blood vessels.  Damage to large blood vessels like arteries (macrovascular) can cause cardiovascular disease resulting in heart attack and stroke.  Damage to small blood vessels like capillaries (microvascular) can cause kidney failure (diabetic nephropathy), and eye damage with loss of vision (diabetic retinopathy).  Damage to nerves (diabetic neuropathy) can result in amputation, particularly of the toes.

How do diabetic medications work?

Diabetic medications that are taken as tablets are known as oral antihyperglycaemics and are classed according to how they work.  They should be used alongside improving diet and increasing exercise and they include:

• Biguanides like metformin improve your body’s response to the effects of insulin, increase the amount of glucose that is stored, and reduce the amount of glucose produced in the liver and absorbed from the diet.
• Acarbose inhibits the action of the enzyme alpha-glucosidase that converts carbohydrates in the diet to simple sugars like glucose, and this reduces the amount of glucose that enters the blood after a meal.
• Thiazolidinediones like rosiglitazone and pioglitazone reduce insulin resistance by increasing the body’s response to insulin and acting directly on cells of the liver, muscle, and fat tissue.
• Sulphonylureas like glipizide increase insulin production by directly stimulating the pancreatic beta cells to produce more insulin.
• Gliflozins like empagliflozin and canagliflozin act directly on the kidneys to inhibit glucose reabsorption from the urine back into the blood, to lower blood glucose levels.
• DPP-4 inhibitors like sitagliptin work by inhibiting the enzyme dipeptidyl peptidase 4 (DPP-4) and preventing the destruction of incretins, which are small proteins released from the intestine after a meal that stimulate insulin production and reduce glucose production by the liver. 

Cardiovascular disease

Cardiovascular disease covers a range of heart and circulation problems that can increase the risk of heart attack and stroke.  These include:

• high blood pressure (hypertension) can damage your artery walls and increase stress on your heart, as well as increasing pressure on smaller blood vessels, such as those in the kidneys, which can lead to kidney damage. 
• heart failure, which is when the heart muscle is weakened and cannot pump blood efficiently.
• coronary heart disease when arteries of the heart become blocked and hardened.
• angina causing shortness of breath chest pain due to reduced oxygen supply to the heart muscle.
• Atherosclerosis, which is when cholesterol is deposited in the arteries causing them to become narrowed and hardened.

A heart attack is caused by restricted blood flow to the heart muscle, resulting in heart muscle cell damage.  A stroke is the result of a blockage in a blood vessel in the brain or a bleed into the brain, which can cause brain cells to die if not treated quickly. 

Risk factors for cardiovascular disease include having high blood cholesterol levels, lifestyle factors like obesity and smoking, and conditions like diabetes. 

Medications for cardiovascular conditions and how they work

We sell a wide range of generic Heart Meds, which are classed according to how they work.  Some of these medications are used only for a specific condition, but others can be used for several conditions.  For some conditions, more than one class of heart medication can be used together for increased effectiveness.

Our generic Heart Meds include:

• ACE inhibitors like enalapril and ramipril are used to treat hypertension and congestive heart failure.  They work by inhibiting the action of Angiotensin-Converting Enzyme, which relaxes and widens blood vessels, reduces blood volume, lowers blood pressure, and helps the heart to pump more efficiently relieving symptoms of heart failure. 
• Angiotensin II receptor blockers (ARB) like valsartan and losartan, are used to treat hypertension and congestive heart failure.  They work by blocking the hormone angiotensin II binding to its receptor, which relaxes and widens blood vessels, reduces blood volume, lowers blood pressure, and helps the heart to pump more efficiently, relieving symptoms of heart failure.
• Calcium channel blockers like diltiazem, amlodipine, and felodipine, are used to treat hypertension and angina.  They work by blocking calcium ions entering smooth muscle cells of blood vessel walls, allowing blood vessels to relax and widen.  
• Diuretics like the hydrochlorthiazide torsemide, are used to treat hypertension and congestive heart failure.  They work by acting on the kidneys to promote the removal of salts and water from the blood, which reduces blood volume, lowers high blood pressure, and helps remove fluid retention in the tissues (oedema).
• Anti-clotting drugs like clopidogrel are used to prevent blood clot formation (thrombosis).  They work by inhibiting platelet aggregation, which reduces the risk of a clot forming in the arteries that can cause heart attack or stroke if it travels to the heart or brain.
• Vasodilators like minoxidil are used to treat poor circulation, hypertension and angina.  They act directly on blood vessel walls, causing them to relax and widen, which allows blood to flow more freely.
• Beta blockers like propranolol and atenolol are used to treat hypertension, angina and arrhythmias (heart rhythm disorders).  They work by blocking the action of certain hormones like adrenaline that act on beta receptors in the heart, which slows the heart rate, widens blood vessels, lowers blood pressure, and increases blood flow and oxygen supply to the heart.  
• Antiarrhythmics like amiodarone are used to treat heart rhythm disorders, including irregular heartbeat (arrhythmia) and rapid heartbeat (tachycardia).  They work by correcting the abnormal electrical activity in the heart. 
• Heart rate lowering drugs called cardiotonic drugs like ivabradine are used to treat coronary artery disease, which is narrowing of blood vessels that supply the heart.  They work by acting directly on the heart muscle to reduce the heart rate.
• Anti-angina drugs like ranolazine are used to treat chronic stable angina, which is a symptom of heart disease.  They work by acting directly on the heart muscle to slow down the rate of muscle contraction, which reduces the need for oxygen and relieves symptoms of angina.

What is an infection?

An infection is when a microbe or microorganism invades the body and replicates, resulting in illness and disease with symptoms including pain, inflammation, fever and sores, depending on the type of microorganism and where the infection is located.  The infective organism is known as a pathogen and can enter the body by several routes, for example, through a wound, by inhalation, in body fluids, in contaminated food, or in a vector (another organism that transmits a pathogen).

An infection can be caused by:

• Bacteria, which are single cell organisms with a cell wall but no nucleus and all equipment needed to replicate their genetic material independently of the host cell.
• Viruses, which are much smaller than bacteria, are surrounded by a protein capsule and cannot replicate independently, instead they use the host cell enzymes to replicate their genetic material, which can be either DNA or RNA.
• Fungi, which are multi-cellular organisms that replicate independently and spread by growing hyphae, as in the case of mould-like fungi called dermatophytes such as tinea, or by budding as in the case of yeasts like candida. 

Bacterial infections and antibiotics

Many bacteria live in the body without causing any harm, such as in the intestines where they help with digestion, or on the skin.  However, if bacteria invade the body, for example through a wound, by inhalation or in food, they can end up in a part of the body they are not meant to be and can become pathogenic by dividing and reproducing rapidly within the cells of the infected tissue.  This is a bacterial infection which can cause illness with symptoms including diarrhoea, fever, pain, inflammation and sores, depending on the type of bacteria and where the infection is located. 

Viral infections and antivirals

Viral infections are due to invasion of the host cell DNA by a virus, which then uses the cell’s enzyme to replicate so that new virus particles can be produced and shed ready to infect another cell, killing the host cell in the process.  

The symptoms of a viral infection depend on the location in the body that becomes infected.  The common cold is caused by infection of the upper respiratory tract and infection of the same tissues with influenza virus causes influenza.  Human Papillomavirus (HPV) infects skin cells, causing warts and is also associated with cervical cancer.  Herpes Simplex virus infects mucous membranes of the genitals (genital Herpes) and lips (cold sores).  Varicella, a Herpes-like virus, causes chicken pox and also shingles (herpes zoster). 

Fungal infections and antifungals

Fungal infections of the skin, scalp and nails are mostly caused by the tinea fungus which spreads through the skin and are commonly known as ringworm.  Yeasts also cause fungal infection, the most common being Candida, which infects mucous membranes of the mouth and vagina causing the infection candidiasis commonly referred to as thrush.  Symptoms of a fungal infection include rash, itching, scaling of the skin and inflammation.

Parasitic infections and anti-parasitics

A parasitic infection is caused by a pathogenic microorganism and includes a range of organisms causing a range of diseases, some severe and life threatening.  A parasite can be a protozoan or single cell organism like plasmodium that causes malaria, amoeba that causes amoebiasis or amoebic dysentery, giardia that causes giardiasis, an infection of the intestines.  Parasitic helminth worms including tapeworm and roundworm cause intestinal infections that can cause severe symptoms.

Parasitic infections are often transmitted into the host by a vector.  For example, the mosquito that transfers the malaria-causing plasmodium when biting, directly into the blood.  Malaria is a life-threatening disease that causes symptoms including, fever, shivering, headache, vomiting, muscle pain, joint pain. Tapeworm infections are caused by ingestion of eggs in infected food or by transmission of the adult tapeworm in faeces, which become ingested due to poor hygiene.  The eggs are transmitted in the faeces of dogs or other mammals such as sheep, depending on the type of tapeworm.  Tapeworm causes a range of symptoms and diseases, depending on the location of the parasite in the body and the stage of its development, including abdominal pain, jaundice, coughing, chest pain, and seizures. 

Neurological disorders

Our brain is the control centre for our whole body.  However, if there is a malfunction somewhere in the central nervous system, which includes the brain, spinal cord, and nerves, this can result in a neurological disorder. 

Epilepsy

Epilepsy is caused by abnormal bursts of electrical activity in the brain resulting in uncontrolled muscular spasm known as seizures, also known as convulsions or fits.  You may experience other symptoms, including emotional and behaviour changes, also strange sensations like feelings of temperature fluctuations or intestinal movements. 

Epileptic seizures are recurrent and can vary in frequency and range from mild to severe.  Seizure type depends on where the abnormal brain activity starts, and how much of the brain is involved.  A generalised seizure affects both sides of the brain at the same time, which in its most severe form, is called a tonic-clonic seizure.  This causes loss of awareness and uncontrollable jerking and twitching movements.  A focal seizure begins in one side of the brain, and awareness can remain.  However, a focal seizure can spread to both sides and become a tonic-clonic seizure.  Causes are often unknown but may be due to genetic changes in the brain, related to a head injury, diseases like Alzheimer’s, a brain tumour, and infection like meningitis.  Specific triggers have been identified, such as hormonal changes, flickering lights, high fever, and some foods. 

Migraine

A migraine is a severe headache usually on one side of the head and is often accompanied by other symptoms including nausea, vomiting and extreme sensitivity to light.  An aura can be the first sign of a migraine attack and includes visual disturbances like zig-zag line and blurring.  Other signals that a migraine attack is imminent include changes in the sense of smell, food cravings, mood changes, repetitive yawning, dizziness, tingling and numbness, and fatigue. 

When a migraine is triggered, it is thought that this stimulates the abnormal release of chemicals in the brain.  These chemicals cause inflammation, pain, and extreme widening (dilation) of brain blood vessels.  These dilated blood vessels press on nearby sensory nerves called the trigeminal nerves and induce pain and other symptoms of a migraine. 

You may have a family member who also suffers from migraines as genetics is thought to play a part in its cause.  Migraine triggers have also been identified.  These include stress, hunger, hormonal changes, some foods like cheese or chocolate, caffein-containing drinks like coffee, and alcohol, amongst others.

Bipolar disorder

Bipolar disorder is a mood disorder that causes mood fluctuations from extremely high elated mood called mania, to extreme low mood that is like depression.  Bipolar disorder is defined by manic episodes and depressive episodes, and the severity and duration of the highs and lows vary.  Manic episodes include being overexcited, agitated or irritable, risky behaviour, not sleeping much and losing touch with reality.  Depressive episodes include feelings of sadness, and low esteem, loss of energy, concentration and motivation, and loss of interest in activities that used to be pleasurable.  In between the highs and lows, it is possible to have spells of balanced mood.

Neurotransmitters are brain chemicals that allow nerve cells to communicate.  A balance between neurotransmitters that are excitatory and those that have a calming effect on nerve cells is essential for the brain to function normally.  Bipolar disorder is thought to be related to an imbalance of brain chemicals. 

Family history has a large part to play in the risk of developing bipolar disorder.  Other triggers include a life-changing event or trauma in childhood or an illness. 

Medications for neurological disorders

Medications for neurological disorders are usually targeted against the cause of the disorder.

These include:

• Lamotrigine, levetiracetam, and oxcarbazepine are anticonvulsants that act directly on nerve cells.  They prevent abnormal electrical activity and repetitive transmission of nerve impulses that cause seizures.  These medications help reduce the frequency and severity of epileptic seizures.
• The anticonvulsant lamotrigine also helps prevent or delay episodes of extreme mood swings in bipolar disorder.  It acts directly on nerve cells and restores the balance between excitatory and calming neurotransmitters.
• Sumatriptan and rizatriptan are used to treat migraine attack to relieve headache and other symptoms.  They work by mimicking the actions of the brain chemical serotonin that causes blood vessels to constrict and narrow.  These drugs also block the transmission of pain signals. 

What is pain?

Pain is a warning, and when you feel pain you know at once that something is wrong.  The type of pain and where in your body you feel it, gives clues about what is causing the pain.  Pain receptors, called nociceptors, are stimulated by triggers that indicate potential damage to the body, such as mechanical forces, chemicals, and extreme heat.  Messages received by pain receptors are sent to the brain to be processed and interpreted as pain.  Burns, cuts, fractures, sprains, and inflammation are examples of nociceptive pain.  This type of pain is usually perceived as aching or throbbing, ranging from mild to severe.

Pain can also be acute or chronic.  Acute pain, such as following an injury or surgery, usually stops as soon as the initial cause has healed.  However, if the pain continues more than six months, it becomes chronic pain, which is often related to a chronic progressive condition like arthritis. 

Types of pain

Inflammation

The inflammatory response to injury and infection is a process that involves cells of the immune system and a range of chemicals produced to protect and heal the injured or infected tissues.  If the inflammation continues after the body has recovered from the injury, chronic inflammation can cause damage such as chronic degenerative joint diseases.  Symptoms of inflammation include redness, swelling, and pain.  

Pain due to inflammation is caused by chemicals, such as prostaglandins and leukotrienes, produced by immune cells produced during the inflammatory response.  It includes.

• Soft tissue injury triggers inflammation such as sprains and strains due to trauma and sports injuries.  Overuse injuries also cause inflammation of tendons (tendinitis, tennis elbow) and inflammation within joints (bursitis and frozen shoulder). 
• Pain following surgery is caused by inflammation. 
• Osteoarthritis often called wear and tear, is caused by the gradual destruction of the cartilage that covers and protects the ends of the bones in an articular joint.  The underlying bones rub against each other, causing inflammation, pain, and stiffness, which restricts the movement of that joint. 
• Rheumatoid arthritis is an autoimmune disease where the immune system attacks and destroys the synovial membrane that forms a protective lining over the joints.  The synovium becomes inflamed and thickened, causing swelling and pain in the joints.  Eventually, the cartilage and bone are damaged, which can cause deformities.

Migraine

A migraine is a neurological disorder that causes an intense, throbbing, and painful headache, usually with other symptoms including nausea, vomiting, and extreme sensitivity to light.  An aura can be the first sign of a migraine attack and includes visual disturbances like zig-zag lines and blurring. 

A migraine attack is thought to be triggered by the abnormal release of chemicals in the brain that causes inflammation, pain, and extreme widening (dilation) of brain blood vessels.  Activation of nearby sensory trigeminal nerves also induces pain and other symptoms of a migraine. 

Genetics is known to play a role as well as specific triggers, including stress, hunger, hormonal changes, some foods like cheese or chocolate, caffein-containing drinks like coffee, and alcohol, amongst others.

Nerve pain

Nerve pain is a different type of pain and is the result of a damaged or malfunctioning nervous system.  Although an injury may be the original trigger, nerve pain continues after the wound has healed because the nervous system has become sensitised.  The nerve pain generated may now be unrelated to the initial injury.  Also, nerve pain sensation is different and is described as electric shocks, stabbing, and burning.

Examples of nerve pain include shingles, trigeminal neuralgia (affects the face and teeth), sciatica (compression of nerves in the spine), phantom limb pain following amputation, and diabetic neuropathy, where peripheral nerves are damaged mainly in the legs and feet.

Neurotransmitters are brain chemicals that allow nerve cells to communicate.  A balance between excitatory and calming neurotransmitters is essential for the brain to function normally.  An imbalance in these neurotransmitters is thought to be involved in causing nerve pain.

Gout and kidney stones

Gout is caused by excess uric acid in the blood.  Uric acid crystals become deposited in the skin, known as tophi, in the kidneys, known as kidney stones, and in the joints, known as gout.  Uric acid crystals cause inflammation, pain, and swelling. 

Dysmenorrhoea

Primary dysmenorrhoea is a common problem for many women, causing painful periods.  At the end of the menstrual cycle, prostaglandins stimulate the uterine muscle to contract and expel the uterine lining.  Prostaglandins are cellular messengers that mediate many cellular processes.  Production of prostaglandins in large amounts can result in increased contractions causing muscle cramps and menstrual pain.

Muscle spasm

Muscle spasm is involuntary and excessive muscle contraction and can be very painful.  This type of muscle spasm is called spasticity or muscle stiffness.  Clonus is a reflex muscle spasm caused by a series of spontaneous involuntary muscle contractions and relaxations.  Muscle spasm can be due to nervous system disorders like multiple sclerosis, motor neuron disease, and cerebral palsy.  Other causes include meningitis, a tumour, following a stroke, or injury to the brain and spinal cord.

Medications for pain

Nonsteroidal anti-inflammatory drugs (NSAID)

Nonsteroidal anti-inflammatory drugs (NSAID) are used to relieve the pain of inflammation.  These include diclofenac, indomethacin, meloxicam, and celecoxib.  All NSAIDs work by inhibiting the action of the enzyme cyclooxygenase (COX).  This enzyme is critical for the synthesis of chemicals called prostaglandins (PG).  Prostaglandins are cellular messengers that mediate many processes.  Some prostaglandins like PGE2 are produced at sites of injury or inflammation and cause pain, swelling, and other symptoms of inflammation. 

There are two forms of COX enzyme.  COX-1 is produced by most cells, including the stomach, and resulting prostaglandins protect the stomach lining.  COX-2 is only induced during the inflammation process and results in the synthesis of inflammatory prostaglandins, particularly PGE2.  Diclofenac and indomethacin are both non-specific COX inhibitors and block the production of both COX-1 and COX-2.  This can cause gastrointestinal side effects due to the inhibition of protective prostaglandins and the disruption of acid regulation.  Celecoxib and meloxicam are specific COX 2 inhibitors and only block prostaglandins that are induced during an inflammatory response.  Diclofenac and indomethacin are used to treat acute and chronic musculoskeletal inflammatory pain, post-operative pain, arthritis (rheumatoid arthritis and osteoarthritis), and dysmenorrhea.  Celecoxib and meloxicam are used primarily to treat rheumatoid arthritis and osteoarthritis.  However, celecoxib is also used to treat dysmenorrhea.

Migraine medications

Sumatriptan and rizatriptan drugs called triptans that are used to treat migraine attack to relieve headache and other symptoms.  They work by mimicking the actions of the brain chemical serotonin, a neurotransmitter that causes blood vessels to constrict and narrow.  These drugs also block the transmission of pain signals. 

Nerve pain drugs

Gabapentin is an anticonvulsant that is used to treat epilepsy.  It also works by the same mechanism to relieve nerve pain.  Gabapentin acts directly on nerve cells in the brain to prevent abnormal electrical activity and repetitive transmission of nerve impulses.  Gabapentin blocks the transmission of excitatory nerve signals, which reduces the amount of nerve excitation that causes epileptic seizures and nerve pain.

Anti-gout medication

Allopurinol is used to treat conditions caused by uric acid crystals, such as gout, kidney stones, and skin tophi.  Allopurinol works by inhibiting the enzyme xanthine oxidase, which plays an important role in the production of uric acid.  This prevents the build-up of uric acid in the blood and helps relieve the pain caused by deposits of uric acid crystal.

Muscle spasm

Baclofen is a muscle relaxant that is used to help relieve painful muscle spasm caused by a variety of injuries and conditions.  Baclofen works by acting directly on nerve cells in the brain to control nerve signals sent to muscle cells that cause them to contract.  This prevents excessive and involuntary muscle contraction causing muscle spasm.

Skin conditions

Acne

Acne is a skin condition usually related to hormonal changes at puberty.  The oil-producing sebaceous glands in the hair follicle over-produce sebum, which, together with dead skin, block the pores in the skin.  These cause skin blemishes like whiteheads (enclosed blockage within a hair follicle) and blackheads (when the plug of sebum and skin cells is pushed to the skin surface).  Spots can also become inflamed and infected, causing pustules and cysts.

Inflammatory skin condition

Inflammatory skin conditions are caused by an overactive immune system.  Symptoms range from mild with itching, redness, and discomfort to severe with blisters, scaly patches of skin, and weeping sores.  They include:

• Eczema, also known as atopic eczema or atopic dermatitis, is an inherited condition that is closely linked to asthma and hay fever.  Eczema is usually found in elbows, behind the knees, and on fingers.  It causes a rash that becomes red and itchy and can be made worse by factors like chemicals on the skin or dry, humid weather.
• Dermatitis is red, itchy, swollen patches of skin usually caused by direct skin contact with an irritant like solvents and harsh chemicals, or in response to an allergic trigger like perfume, latex or nickel
• Psoriasis is a non-allergic autoimmune condition, where the immune system attacks self, and it causes dry patches of thickened scaly skin over the body.

Rosacea and scabies

Rosacea is characterised by a red rash found mainly on the face.  It is an inherited disorder but is also made worse by factors like sun exposure, cold temperatures, strong winds, some medications like steroids, certain foods, cosmetics, and stress.

Scabies is caused by an allergic reaction to the parasitic mite Sarcoptes scabiei that burrows into the skin, causing irritation and itching.  A rash can develop over the whole body resulting in severe itching and discomfort.

Rosacea symptoms can be exacerbated (made worse) by scabies, which is thought to trigger inflammation.

Fungal skin infections

Fungal infections of the skin caused by tinea can affect many parts of the body.  These include between the toes (athlete's foot), ringworm of the body (tinea corporis), tinea of the groin and tinea of the scalp (tinea capitis).  Candida is a yeast-like fungus that infects mucous membranes, usually in the mouth, throat, and genitals.  It is commonly referred to as thrush, which is seen as white patches in the mouth that can become painful.  Symptoms of fungal infections of the skin include inflammation, itching, and rash, which can become severe.

Hirsutism

Unwanted growth of facial hair in women is called hirsutism.  It is often associated with high levels of androgen hormones in conditions such as polycystic ovary syndrome (PCOS). 

Topical treatments for skin conditions

• Topical antibiotics like dapsone are used to treat acne to help clear blemishes and prevent the spread of bacterial infection from an infected spot.
• Retinoids like tretinoin are used to treat severe acne by reducing inflammation.  Retinoids are keratolytic and work by softening hardened cells that clog pores.  They also promote new cell growth to help heal skin blemishes.
• Azelaic acid has antibacterial and keratolytic properties and is used to treat mild acne.
• Topical corticosteroids like desonide and clobetasol are used to treat inflammatory skin conditions like eczema, dermatitis, psoriasis and rosacea.  They work by blocking inflammation and reducing irritation so that the skin can heal. 
• The anti-parasitic ivermectin is used to treat scabies and rosacea, where high numbers of scabies parasites have invaded the skin, causing inflammation.
• Antifungals like terbinafine are used for fungal skin infections like tinea and candida.
• Eflornithine reduces the production of unwanted facial hair in hirsutism by blocking an enzyme in hair follicles of the skin that stimulates hair growth.

Why is cigarette smoking addictive?

Cigarettes contain many toxic chemicals that are drawn into your lungs each time you drag on a cigarette and can seriously damage your health.  Cigarette smoking has been linked to heart disease, stroke, and cancer.

However, it is the nicotine in cigarettes that is the addictive chemical.  Nicotine is a natural pesticide found in the tobacco plant.  It very poisonous and one of the most addictive known drugs.  When nicotine is inhaled into your lungs in cigarette smoke, it is rapidly absorbed into the blood and reaches the brain within seconds.  The effects of nicotine are immediate.  You will feel an adrenaline rush, as it stimulates adrenaline release from the adrenal glands.  In the brain, nicotine stimulates the release of the neurotransmitter dopamine, a brain chemical that allows nerve cells to communicate.  Dopamine is often referred to as the “feel good” hormone as it is released when the reward circuit is activated.  Dopamine creates a feeling of pleasure and relaxation when activated by a pleasurable activity like eating or sex.  The amount of dopamine released by a drug like nicotine is much greater.  It creates a feeling of euphoria, leading to the desire to repeat the feeling, which soon becomes a need and is the start of an addiction. 

Withdrawal symptoms

If you continue to smoke, you will gradually need more and more nicotine to get the same effect.  If you stop smoking, once you are nicotine dependent, you will suffer from unpleasant withdrawal symptoms.  These include physical symptoms like sweating, tremor, increased pulse rate (tachycardia), and nausea; also, emotional symptoms like anxiety, irritability, confusion, depression, and insomnia.  

How do medicines work to help you quit smoking?

Medications to help you quit smoking work by helping you break the addiction for nicotine and reducing the withdrawal symptoms while you stop smoking.  They include:

Varenicline

Varenicline has a similar structure to nicotine.  It binds to the same receptors that nicotine binds to, which are the nicotinic acetylcholine receptors.  These receptors stimulate dopamine release, but varenicline produces a much weaker response so that the reward effect and the craving are both gradually reduced. 

Bupropion

Bupropion is an antidepressant that helps break the addiction created by nicotine dependence and works by increasing the amount of dopamine in the brain without the need for nicotine.  Bupropion blocks the reuptake of dopamine from the nerve cells that release it, which prolongs the time that dopamine is active in the brain.