Week 33

Welcome back to our pharmacology topic.

Pharmacology recap

Quizzes serve as effective tools for assessing your knowledge and reinforcing learning through immediate feedback. Complete the following 9-question pātaitai (quiz) to have some fun and support your learning!

Note: If you happen to answer a question incorrectly and are unsure why, don't hesitate to discuss it with your tutor for clarification and guidance.

Ināianei, now, let’s now turn our attention to pharmacology in specific populations.

Pregnancy (Haputanga)

The normal physiological changes that occur during pregnancy can alter the way drugs are absorbed, distributed, metabolised and excreted, potentially affecting both the mother and the developing foetus.

As you can see here, the placenta takes on a crucial role in the development of the baby. It not only filters waste and passes on oxygen, but it is a gatekeeper, protecting the baby from toxins, parasites and pathogens. It also distributes hormones.

The effect of drugs on pregnancy

Most drugs cross the placenta from the mother’s bloodstream to the foetus’s and may have harmful effects on the foetus at any stage of pregnancy. Some drugs are only harmful if given at certain stages of the pregnancy.

• During the first trimester, which is when the foetus is developing, drugs may cause permanent birth defects (this is called teratogenicity) in the foetus. 
• During the second and third trimesters, drugs may affect the growth and development of the foetus, or they may have toxic effects.

Here, you can see these critical stages of foetal development and the times of greatest vulnerability:

Prescribing medicines

What factors would a prescriber take into consideration when prescribing medicines to a pregnant person?

How many factors can you think of? Challenge yourself to list at least two factors, before clicking on the (+) to compare your answers.

Factors to consider when prescribing in pregnancy:

Advice on prescribing in pregnancy is found on the New Zealand Formulary (NZF) website. It provides information that is specific to a drug and gives an indication of the risks involved and what to expect. Some of this information comes from Wolters Kluwer Health's renowned resource called Drugs in Pregnancy and Lactation. 

Breastfeeding (Whakangote)

Most drugs cross into the breast milk, but often at concentrations too low to cause harm. It is still best to avoid taking drugs while breastfeeding. As previously mentioned, information on specific drugs during pregnancy and lactation (breastfeeding) can be found on the NZF.

Taking drugs during breastfeeding

If it is necessary to take drugs during the period of breastfeeding, it is safest to feed the baby just before taking the dose, when blood levels in the mother will be lowest.

If the drug is unsafe for the baby, expressing and discarding breast milk during treatment helps maintain milk production until breastfeeding can resume safely.

Infants and children (Kohungahunga me nga tamariki)

Pharmacological management in infants and children requires careful consideration of their unique physiological characteristics and developmental stages.

Prescribing medicines

Factors to consider when prescribing for infants and children include:

1. Age
2. Physiology and dosage
3. Developmental changes

Haere tonu, continue on to read more about each factor.

Age-related variations in drug metabolism and elimination

• Infants and children have different metabolic rates compared to adults, which can affect how drugs are processed and eliminated from their bodies. 

Physiology and dosage

• Infants and children have immature organ systems, such as the liver and kidneys, that are still developing, which may affect drug metabolism and excretion. 
• Factors like body composition and surface area may influence drug distribution and dosing. 
• Babies and young children are often dosed by weight rather than a standardised dose. 
• Low therapeutic index drugs need to be carefully monitored, especially in neonates (newborns). 
• Children from the age of 12 are usually treated as adults.

Developmental changes

• As children grow and develop, their pharmacokinetic and pharmacodynamic profiles change. 
• This can impact drug efficacy and safety over time, requiring adjustments in dosing and monitoring.

There is a separate New Zealand Formulary for children, which can be found here: nzfchildren.org.nz.

It’s a good idea to bookmark this webpage on your browser or note it down for future reference.

Elderly (Kaumatua)

Pharmacological management of patients in the older adult age range requires several factors due to age-related changes in physiology and potential comorbidities.

Prescribing medicines

Key considerations when prescribing include:

1. Liver function
2. Renal function
3. Drug sensitivity
4. Comorbidities and polypharmacy

Again, let’s look at these in more detail.

Liver function

• Aging affects liver enzymes responsible for drug metabolism, leading to slower metabolism and prolonged drug half-lives.

Renal function

• Kidney function declines with age, resulting in decreased drug clearance and increased risk of drug accumulation and toxicity.

Drug sensitivity

• Older adults may be more sensitive to certain medications due to changes in drug distribution and receptor sensitivity. 
• They are more susceptible to adverse drug reactions due to age-related changes in pharmacokinetics and pharmacodynamics, as well as increased sensitivity to medications such as those with sedating properties.

Comorbidities and polypharmacy

• Aging is associated with a higher prevalence of comorbidities (more than one disease), which may necessitate the use of multiple medications (polypharmacy).
• This increases the complexity of drug therapy and the risk of drug interactions and adverse effects.

Summary

Summarise your learning of this section in the following activity.

That wraps up this pharmacology session. Ka pai temahi, good work.

In this week of Anatomy and Physiology, we look at a musculoskeletal disorder before moving on to disorders of the integumentary system, eye and ENT. The content will continue to build on what you already know. 

There is a lot to cover, so get yourself ready and hoake tātou! Let’s go!

Occupational Overuse Syndrome (OOS)

Occupational Overuse Syndrome, formally known as RSI (Repetitive Strain Injury), is an umbrella term for a range of conditions that cause discomfort or persistent pain in muscles, joints, tendons, nerves and soft tissues.

Causes

Occupational Overuse Syndrome can have various causes, typically associated with repetitive or prolonged activities in the workplace.

Some common causes include the following:

• Repetitive tasks or movements, such as typing, using a mouse, or assembly line work, can strain specific muscles or joints over time.
• Inadequate workspace setup, improper chair or desk height, and lack of ergonomic tools.
• Using excessive force or exerting too much pressure during tasks can lead to strain on muscles and joints.
• Maintaining awkward or uncomfortable positions for extended periods, especially if the body is not properly supported.
• Prolonged exposure to vibrating tools or machinery can contribute to muscle and joint fatigue.
• Inadequate breaks or insufficient recovery time between repetitive tasks.
• Personal factors such as overall health, fitness levels, and pre-existing medical conditions can also influence the likelihood of developing OOS.

Treatments for OOS

Once a diagnosis of OOS has been made and the specific OOS condition has been identified, appropriate treatment will be recommended.

This may involve referral to an occupational or musculoskeletal specialist and may involve input from healthcare professionals such as occupational therapists and physiotherapists.

As this is a condition that may even affect you in your career, challenge yourself to consider if there are any treatments that you would suggest or already do to mitigate OOS. When you’re ready, expand the label to compare your answers.

Integumentary system

Previously, we looked at the structure and function of the integumentary system and the disorders of acne, dermatitis and eczema. Building on this knowledge, we will continue to investigate our investigation of integumentary disorders, this week focusing on seborrhoeic dermatitis and acne.

Seborrhoeic dermatitis

Seborrhoeic dermatitis is a type of dermatitis caused by a yeast or fungus. It can cause dandruff, a common condition where the scalp is itchy and skin flakes without any signs of inflammation.

Treatments

Treatment typically involves a combination of self-care measures and medications. Pharmacological treatments include:

Topical Antifungal Agents

• Often prescribed in the form of medicated shampoos, creams, or lotions containing antifungal agents such as ketoconazole, ciclopirox, selenium sulfide, zinc pyrithione, coal tar, and salicylic acid. 
• They help reduce inflammation and control the overgrowth of yeast on the skin.
• Example: Ketoconazole 1% Shampoo (Nizoral, Sebizole). 
  • It is applied as a shampoo to wet hair. Once applied, it is left on the hair for 3-5 minutes before rinsing. It is used twice weekly for at least a month. 

Topical steroids

• Corticosteroid creams or lotions may be prescribed to reduce inflammation, which works by reducing the inflammation in the affected area to reduce the redness, swelling, and itchiness of the skin. 
• Example: Betamethasone Valerate Scalp Lotion 0.1% (Betnovate lotion).
  • This lotion is applied sparingly to the affected areas of the scalp, once or twice daily, for no more than four weeks at a time.

Acne vulgaris

In your previous learning, you carried out an activity identifying the features of acne.

Optional refresher

If you’re confident in identifying the types, symptoms, treatments, and medicines for acne and dermatitis, haere tonu, continue on. Otherwise, you may want to retry this activity to revise what you have learned.

Causes of acne

Acne is a common skin condition that mostly affects young adults in puberty. It is caused by inflammation of the sebaceous glands of the face and sometimes the chest and the back.

Hormonal changes related to menstruation or pregnancy can also cause or contribute to acne. Environmental irritants such as pollution, intense heat, humidity, or cold can also be contributing factors.

During puberty, the production of male sex hormones (androgens) increases in both sexes, which stimulates the sebaceous glands to produce more sebum. In some people, the sebaceous glands are extremely sensitive to androgens. This increased sebum production narrows the openings of the sebaceous glands, and the sebum builds up in the pore.

Sebum and dead epithelial cells block the pore, forming a plug called a comedome – a whitehead. The comedome oxidises on contact with air and turns black – a blackhead. Often, there is involvement of a common skin bacteria that lives on the fatty acids found in sebum. The bacteria produce waste products and fatty acids that irritate and inflame the sebaceous glands.

Symptoms

The first symptoms are small, tender, red spots that later turn into pimples containing degraded fatty acids. The inflammation disappears over a few days or weeks, depending on the severity. Severe acne can cause scars, so an early, effective treatment is important.

Acne or pimple formation

Treatments for acne

There are various treatments for acne, depending on the severity. Mild acne can be treated with OTC products, but more severe forms require medical attention for assessment and treatment with prescription medications.

Treatments may include:

Topical antiseptics

• Kills or inhibits the growth of bacteria on the skin's surface, helping to reduce the number of acne-causing bacteria and prevent infection.

Keratolytics

• Helps to exfoliate (remove dead skin cells) the outer layer of the skin, unclog pores, and remove dead skin cells, which can contribute to the formation of acne lesions.

Keratolytics with topical antibiotics

• This combined treatment can help to address both the clogging of pores and the bacterial component of acne, reducing inflammation and preventing new acne lesions from forming.

Keratolytics with topical antibiotics and topical anti-inflammatory

• This combination targets multiple aspects of acne formation, including pore blockage, bacterial growth, and inflammation, providing comprehensive treatment for acne.

Topical retinoids

• Help to unclog pores, reduce inflammation, and promote the turnover of skin cells, leading to smoother and clearer skin.

Oral antibiotics

• Prescribed to target the bacteria involved in acne formation, reducing inflammation and preventing the spread of infection.

Oral isotretinoin

• An oral medication that is reserved for severe cases of acne that have not responded to other treatments.
• It works by reducing the size of the sebaceous glands in the skin and the production of sebum (skin oil).
• It also inhibits the growth of bacteria and helps prevent the clogging of hair follicles.

The eye (karu or whatu)

In previous content, we looked at the eye (pun intended). The disorders we discussed were conjunctivitis and dry eye. Let’s shift our focus now to another eye disorder, Glaucoma.

Glaucoma

Glaucoma is a condition where there is damage to the optic nerve, often due to increased pressure within the eye. This elevated intraocular (inside the eye) pressure can result from various factors, including impaired drainage of aqueous humour, a fluid that normally flows in and out of the eye.

The increased pressure compresses and damages the optic nerve, leading to vision loss, initially in the peripheral field and eventually progressing to central vision if left untreated.

Watch: Glaucoma […] (3:05 minutes)

Watch this animated video to see how issues with the normal functioning of the eye result in damage to the optic nerve and vision.

Types of glaucoma

As you heard in the video, there are two main types of glaucoma:

1. Open-angle: This occurs when the drainage angle within the eye remains open, but the drainage channels become clogged over time. 
2. Angle-closure: This occurs when the drainage angle of the eye becomes blocked, leading to a sudden increase in eye pressure. 

Symptoms

Glaucoma often develops slowly and without noticeable symptoms until the disease has progressed significantly. Symptoms may include:

• Eye pain or pressure
• Headaches
• Rainbow-coloured halos around lights
• Low vision, blurred vision, narrowed vision (tunnel vision) or blind spots
• Nausea and vomiting
• Red eyes.

Closed-angle glaucoma has more severe symptoms that tend to come on suddenly.

People at higher risk of developing glaucoma include people who: 

• Are older than 40 years
• Have a family history of glaucoma
• Are either short-sighted or long-sighted
• Have a history of migraine or Raynaud syndrome
• Use cortisone or steroids
• Have a previous eye injury.

Treatment

Treatment can’t cure glaucoma, but it can slow down the progression. Treatments for glaucoma that prevent further damage to the optic nerve are ones that lower the intraocular pressure. The most common way to do this is through administration of medicated eye drops. 

Here are two different types of eye drops that can be used.

Prostaglandin analogues

• These work by mimicking the action of naturally occurring prostaglandins in the eye, leading to relaxation and widening of the eye's drainage channels (known as the trabecular meshwork). 
• This allows for better outflow of aqueous humour from the eye, effectively lowering intraocular pressure.
• Example: Latanoprost (Teva®).

Beta-blockers

• Beta-blockers work by blocking the action of beta-adrenergic receptors found in the ciliary body of the eye.
• The ciliary body is responsible for producing aqueous humour. 
• By blocking these receptors, beta-blockers reduce the activity of the ciliary body, leading to a decrease in aqueous humour production with a subsequent reduction in intraocular pressure.
• Example: Timolol (Arrow-Timolol®).

Ear, nose and throat (ENT) disorders

Earlier in your learning, we discussed the parts of the body that make up the ENT speciality and lightly touched on a few conditions that affect these body parts. This week, we will focus on otitis media, hay fever, xerostomia and strep throat.

Otitis media (Pokenga taringa)

As we briefly touched on otitis media, answer the following two questions to check your memory. As some of the information is new, you may need to make some educated guesses!

Otitis media is an inflammation or infection of the middle ear, usually caused by bacteria or viruses. It typically occurs when the eustachian tube, which connects the middle ear to the back of the throat, becomes blocked or swollen, leading to fluid buildup behind the eardrum. This buildup can create an environment conducive to bacterial or viral growth, resulting in infection.

Symptoms

Symptoms can include:

• Ear pain that can be mild to severe pain, particularly when lying down or chewing.
• A feeling of fullness or pressure in the ear.
• Temporary hearing loss or muffled hearing.
• Fluid or pus draining from the affected ear, especially if the eardrum has ruptured.
• In some cases, otitis media may be accompanied by fever, particularly in children.
• Balance and coordination problems with associated nausea.
• Severe cases can lead to complications such as hearing loss, glue ear or the spread of infection to nearby structures.

Treatments

Treatments for otitis media include the following:

Antibiotics

• Antibiotics eliminate the bacteria responsible for the infection and help prevent potential complications, such as the spread of the infection to nearby structures like the mastoid bone or the development of chronic otitis media.
• As the site of infection is behind the ear drum, antibiotic ear drops will not be effective. 
• Therefore, the route of administration is oral for its systemic effect and ability to reach the site of infection. 

Analgesics

• Panadol or ibuprofen may be recommended to relieve pain and reduce fever.

Decongestants or antihistamines

• Decongestants or antihistamines may be prescribed to help alleviate nasal congestion and promote drainage of fluid from the middle ear.

Antiemetics

• Where nausea is severe or persistent, antiemetics may be prescribed to provide symptomatic relief from nausea.

Hay fever (Mate hei)

Hay fever is a disorder that affects the upper respiratory tract, primarily the nose. As we have already explored hay fever earlier in this programme, you will be familiar with some of the symptoms, causes and treatments.

Treatments 

Treatments for hay fever include OTC products and prescription medicines. These include:

• Oral antihistamines
• Topical antihistamines (nasal and ocular)
• Topical corticosteroids (nasal)
• Decongestants (nasal and oral)
• Medicated and non-medicated eye drops
• Saline nasal products
• Natural/herbal products.

Xerostomia

Xerostomia, commonly known as dry mouth, is a disorder of the mouth characterised by a lack of saliva production.

Causes

Xerostomia can be caused by various factors, including medications, radiation therapy, autoimmune diseases, and dehydration.

Symptoms

Symptoms of xerostomia may include:

• persistent dryness in the mouth
• difficulty swallowing
• altered taste sensation.

Complications

Complications associated with untreated xerostomia may include:

• Tooth decay
• Burning sensation in the mouth
• Oral infections
• Gum disease 
• Thick or stringy saliva
• A dry or sore tongue
• Bad breath (halitosis)
• Difficulty speaking and swallowing.

Treatments

Management of xerostomia typically involves addressing the underlying cause, maintaining good oral hygiene, and using artificial saliva substitutes or medications to stimulate saliva production.

Non-Pharmacological treatments

Patients can do the following to help address or mitigate some of the symptoms and causes:

• Have good daily oral hygiene.
• Attend regular dental checkups.
• Drink frequent sips of water or suck ice cubes to moisten their mouth.
• Suck sugar-free sweets or chew sugar-free gum to stimulate saliva. 
• Avoid alcohol, caffeine and smoking.
• Use OTC saliva substitutes or oral moisturisers.
• Use saliva substitutes that are extemporaneously prepared (compounded in the pharmacy).
• Apply lip balm or lip moisturiser to prevent drying and cracking. 

Pharmacological treatments

Here are some examples of OTC oral moisturisers: Xerostom® products. 
These products come in various forms, such as mouth sprays, lozenges, gels, or mouth rinses. They act as oral wetting agents and lubricants to alleviate symptoms of dry mouth.

Mouth spray	Mouthwash	Pastilles	Saliva substitute gel	Toothpaste
Images from: Pharmacy Direct.

Strep throat

Strep throat is a bacterial infection caused by Group A Streptococcus bacteria. It primarily affects the throat and tonsils. It is common in the winter months and in crowded living conditions and mostly affects people aged five to 15.

Some people are carriers of Group A Streptococcus. These people have the bacteria in their throats all the time without becoming ill, but they can cause illness in others by spreading the bacteria.

It is believed that up to 15 per cent of school children are asymptomatic carriers. It is spread through coughing, sneezing, and sharing cups and utensils and has an incubation period of between two days to one week.

Symptoms

• Sore throat
• Difficulty swallowing
• Fever
• Red and swollen tonsils that may be covered in pus
• Swollen lymph nodes in the neck
• Headache
• Fatigue
• Nausea or vomiting 

Complications

If left untreated, Group A Streptococci infections can lead to the following serious complications.

For each complication listed, challenge yourself to write down the body parts that it affects and its symptoms before selecting the (+) symbol to expand the label.

Treatments

Treatments for strep throat include the following:

• Antibiotics such as penicillin or amoxicillin kill the bacteria causing the infection.
  • These are normally given for ten days.
• OTC pain relievers such as paracetamol or ibuprofen may also be recommended to alleviate symptoms like fever and sore throat.
• Throat spray or pain-relief (anaesthetic) lozenges.

Self-care measures

• Eating soft foods that are gentle on the throat.
• Ensuring adequate nutrition. 
• Gargling with warm salt water. This can soothe a sore throat, help eliminate bacteria and lessen inflammation.

Ko koe a runga, you are awesome. You made it to the end of this session. Your SDL activities for this week will enhance your knowledge of hay fever treatments, so make sure to complete them!