Unit 12: Diseases and Infections
C: Understand how infectious diseases can be treated and managed
Treatment of infectious diseases
This report will evaluate, compare and describe the different treatment methods for serious
infectious diseases (caused by bacteria, viruses, fungi, parasites or protozoa) as well as the suitability,
problems and contraindications to their uses.
There are several different types of treatments for infectious diseases; this report will focus on 14
different treatment methods:
● Antibiotics
● Antiviral drugs
● Antiretroviral drugs
● Antifungal drugs
● Antimalarial drugs
● Anthelmintic drugs
● Antiprotozoal drugs
● Oral rehydration therapy (ORT)
● Immunoglobulin therapy
● Live attenuated vaccines
● Inactivated vaccines
● Subunit vaccines
● Toxoid vaccines
● DNA vaccines
Antibiotics
Antibiotics can be used to treat diseases caused by bacteria. They can treat respiratory infections
such as pneumonia [1]. Pneumonia is a bacterial disease which is caused by Streptococcus
pneumoniae bacteria [2].
Delivery method
Pneumonia can be treated with amoxicillin, a type of penicillin antibiotic [3]. Amoxicillin is available
in capsule, tablet, chewable tablet and liquid suspension forms [4]. It is often administered every 12
hours (twice daily) or every 8 hours (three times daily), with or without food [4]. The length of
treatment is determined by the type of infection that the patient has [4]. Amoxicillin should be taken
at the same time each day [4]. Follow the instructions on the prescription label exactly and ask your
doctor or chemist to explain any parts you do not understand [4]. Amoxicillin should be taken exactly
as indicated [4].
Mechanism of action
Amoxicillin has an extra amino group bonded to the penicillin [5]. This makes amoxicillin an
aminopenicillin [5]. Aminopenicillins are beta-lactam antibiotics that function by preventing the
synthesis of bacterial cell walls [6]. Peptidoglycan is the compound that makes up the cell walls of
,Unit 12: Diseases and Infections
C: Understand how infectious diseases can be treated and managed
bacteria - it is made up of long, parallel strands of amino polysaccharides [7]. These are composed of
alternating segments of N-acetylmuramic acid (NAM) and N-acetylglucosamine (NAG) [7].
Tetrapeptide and pentapeptide chains protrude from the terminals of NAM subunits [7]. Through a
process called transpeptidation, these peptide chains can form connections with other peptide
chains from the nearby strands with the help of penicillin binding proteins (PBPs) [7]. The
pentapeptides have certain binding sites that they can attach to [7]. The PBP enzymes fuse them
together, strengthening the cell wall and forming an essential link between the two amino
polysaccharide strands [7]. PBP enzymes will incorrectly bind to the beta lactam antibiotic molecule
rather than a tetrapeptide and remain inside the PBP forever, permanently disabling it [7]. As
additional PBPs become disabled, crosslinking stops and the wall becomes weak and unstable [7]. If
the damaged bacteria tries to divide, its cell wall will collapse, which eventually kills them [7].
Effectiveness
Amoxicillin is a broad-spectrum antibiotic which makes them highly effective against many different
types of bacteria, including Streptococcus pneumoniae [8]. Amoxicillin is well absorbed when given
orally and it reaches therapeutic quantities in a variety of bodily tissues and fluids [8]. This allows it
to fight infections in several regions of the body like the respiratory tract, urinary tract, skin and soft
tissues [8]. Another advantage is that amoxicillin is easily accessible since it is available in various
different forms depending on the individual’s personal preference [8]. It is also cost-effective [8];
500mg amoxicillin capsules can be purchased for under £2 from local pharmacies [9]. Although
amoxicillin is generally well tolerated, it may cause some side effects such as nausea, diarrhoea and
skin rashes [8]. However, these are temporary and resolve once the length of treatment is completed
[8]. Another disadvantage is that amoxicillin may not be appropriate for everyone [8]. People who
are allergic to penicillin or other beta-lactam antibiotics should avoid taking amoxicillin since it might
induce potentially dangerous adverse reactions [8]. Individuals with liver or kidney problems should
also discuss their medical history with a doctor before beginning to take amoxicillin [8]. It is essential
that the full course of amoxicillin is taken because if the full course is not taken, then amoxicillin will
not work effectively and the individual will have a higher risk of developing the disease again in the
near future or even antibiotic resistance - this may be an issue for people who forget to take their
medication on time. Antibiotic resistance develops when bacteria become increasingly resistant to
the effects of antibiotics [8]. As a result of this, antibiotics may become ineffective in treating certain
bacterial diseases [8].
Another way that pneumonia can be treated is through antiviral medications. An example of an
antiviral drug that can be given for pneumonia is oseltamivir (brand name Tamiflu)[11]. Both
antibiotics and antivirals can help to treat infectious diseases and they both do this by destroying the
disease-causing pathogens. Amoxicillin works against pneumonia by inhibiting cell wall synthesis and
peramivir works against pneumonia by inhibiting the influenza virus neuraminidase; this is the virus
responsible for releasing viral particles into the body as a result of developing pneumonia [12].
Antibiotics and antivirals both require a prescription before being purchased and used. They are also
used for a certain time duration to ensure that the disease has been completely eradicated. Similar
to antibiotics, the full course of antivirals must be finished so that pneumonia does not reinfect the
individual taking them. This is because antivirals can also develop resistance to certain viruses -
,Unit 12: Diseases and Infections
C: Understand how infectious diseases can be treated and managed
known as antiviral resistance. There are some broad differences between antibiotics and antivirals.
Since antibiotics are a type of medication with broad spectrum activity, they can fight against several
different bacteria. However, antivirals do not have this characteristic as they are only restricted to
treating a specific type of virus; this implies that they have narrow spectrum antiviral activity. In the
case of pneumonia, the antiviral oseltamivir can only prevent the spread of the influenza virus [13].
The cost of antibiotics and antivirals varies significantly, oseltamivir tends to be more expensive than
amoxicillin. A box of 10 oseltamivir capsules (75mg) costs approximately £29.99 [14]. This can heavily
impact a person financially as they would have to make difficult decisions between purchasing
medication and food, or paying bills [15]. Antivirals are less accessible than antibiotics since antivirals
are only mainly administered through oral tablets that must be swallowed with water [16], whereas
antibiotics are available in various forms.
Suitability
Amoxicillin should not be used if there has ever been an allergic reaction or a significant skin reaction
to amoxicillin or any other beta-lactam antibiotic [17]. If a patient has a history of anaphylaxis,
urticaria, or rash following penicillin administration, amoxicillin should not be administered since
these patients are susceptible to acute hypersensitivity reactions, which can include rashes and
anaphylaxis [18]. If a patient experiences hypersensitivity to cephalosporin, amoxicillin should be
prescribed with extreme caution; this is due to evidence of incomplete cross-allergenicity data [18].
Patients who are on warfarin should let their doctor know since amoxicillin may change the
medication's anticoagulant effects [18]. These patients should have their international normalised
ratio (INR) tested 4–7 days following the beginning of the antibiotic treatment [18]. Pregnant women
are able to take amoxicillin since there is no confirmed evidence that it can harm a foetus [19].
Furthermore, there is no increased chance of miscarriage or stillbirth in women taking amoxicillin
[19]. Some people may have misconceptions about the effect that antibiotics have on the body [20].
According to a study in Indonesia, people believed that antibiotics could be taken without a
prescription and that they are a type of medication used to treat any disease or medical symptoms
[20]. Some other beliefs included: antibiotics do not have any side effects, antibiotics can cause
antibiotic resistance when taken for the wrong reasons, antibiotics must be taken as soon as a fever
is developed [20]. This misconception led to a high demand for antibiotic prescriptions in Indonesia
[20]. Therefore, it is highly recommended that people around the world are educated on the
different types of medication and to disregard any taboos surrounding them if needed. This is crucial
so that people are being treated for the right reasons and can recover at a suitable rate.
Antiviral drugs
Antiviral drugs are used to treat diseases caused by viruses. Antivirals can treat diseases such as
hepatitis C, which is caused by the Hepatitis C virus [21].
Delivery method
Hepatitis C can be treated with the antiviral drug daclatasvir [21]. The antiviral drug daclatasvir can
be taken orally in the form of a film coated tablet [22]. The recommended dose is 60 mg of
daclatasvir in combination with 400 mg of sofosbuvir once every day for 24 weeks [22]. Daclatasvir
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C: Understand how infectious diseases can be treated and managed
can be taken either with or without food [6]. If a patient misses a dose of daclatasvir, the medication
should be taken as soon as possible if remembered within 20 hours of the planned dose time [22]. If
a missed dose is remembered more than 20 hours after the planned dose, the dose should be missed
and the next dose should be taken at the proper time [22].
Mechanism of action
Daclatasvir treats HCV by directly targeting the NS5A protein, which is involved in the formation of
membrane networks and the assembly of new virions [23]. Daclatasvir inhibits the production of new
membrane networks and the formation of replication complex vesicles in two ways [23]. It then
interferes with an early step in the assembly of viral particles [23]. Viral assembly is prevented by
blocking the transport of the HCV RNA genome to assembly sites [23]. The combined approach
causes HCV proteins to cluster, inhibiting the generation and release of viral particles and replication
complex vesicles [23]. This comprehensive mode of action is responsible for daclatasvir's success in
preventing HCV replication in cultured cells and treating HCV-infected patients [23].
Effectiveness
Daclatasvir can be used for all genotypes of Hepatitis C: genotypes 1, 2, 3 and 4 [24], making it
convenient for all individuals with Hepatitis C. The combination therapy treatment using daclatasvir
and sofosbuvir has a high sustained virologic response (SVR) rate in patients with genotypes 1 and 4
[25]. This is advantageous because a high SVR rate indicates that the hepatitis C virus would not be
identified in the blood 12 weeks or more after combination therapy is completed [26]. One of the
disadvantages of daclatasvir is that it is significantly expensive. The average cost of daclatasvir and
sofosbuvir is £59,501 for a 12-week combined course and £119,002 for a 24-week course [27]. When
ribavirin is included, these costs rise to between £60,304 and £120,608 [27]. This could impact a
person financially and put them off purchasing antivirals to alleviate their symptoms. As with
antibiotics, daclatasvir can also cause antiviral resistance. Because of this, it is important to finish the
full prescribed course of antivirals to prevent reinfection. Antivirals can have unwanted side effects
[28]. The most common side effects of sofosbuvir when combined with daclatasvir are fatigue,
nausea, headache and insomnia [28].
Tenofovir alafenamide (TAF) is an example of an antiretroviral drug [29]. Both TAF and daclatasvir are
used to treat viral infections and are specific to treating one type of virus; TAF is solely prescribed for
HIV and daclatasvir is usually the first line treatment for Hepatitis C. Both drugs work to treat their
disease through inhibition of viral replication [23] [30]. The prescription methods vary for both types
of medication. TAF is available as a 25 mg tablet taken once a day [31] and daclatasvir is available as a
tablet and oral suspension. Daclatasvir can be used for several genotypes of Hepatitis C whereas TAF
has only been proven to be effective against HIV-1 [32]. TAF has several more side effects than
daclatasvir. These include allergic reactions, bone pain, breathing problems, dizziness, irregular
heartbeat, muscle pain, nausea, vomiting, unusual stomach pain and signs of a fever [33].
