PREFACE
The use of antiretroviral therapy can effectively control HIV and its
disease progress.
Successful treatment depends on how you know about and get the most from
your medicine over a long period of time.
Stay on your medication and work together with your health care providers
is a smart way to reach the goal.
This booklet aims to promote your understanding about how antiretroviral
therapy can help you live a longer and healthier life.
If you have further questions after reading this booklet, please be sure
to talk to your doctor and / or other health care providers to obtain
the feedback.
1. The Human Immunodeficiency Virus
(HIV) life cycle
HIV enters a healthy CD4 cell. Once inside the cell,
HIV coverts its own genetic material RNA into DNA using the enzyme reverse
transcriptase. This new DNA acts as a blueprint directing the infected
cell to make new virus particles. Mature viral cores are produced through
action of viral protease after budding. The new virus is then released
and can infect other healthy cells. Thus, the function of immune system
will be progressively destroyed.
2. What is antiretroviral
therapy (ART) ?
The antiretroviral agents attack HIV at different stages of its life cycle
to inhibit HIV replication and thus bring the viral load down. Combination
therapy of two or more drug components has become the standard of treatment
of HIV disease.
Cocktail" is a colloquial term for HIV combination therapy.
Highly active anti-retroviral therapy (HAART)
HAART refers to very potent regimen in which almost invariably inhibits
viral replication to an undetectable level in the blood. An example of
HAART is the use of triple therapy comprises 2 Nucleoside Reverse Transcriptase
Inhibitors (NRTI) and 1 Protease Inhibitors (PI).
3. Effects of antiretroviral therapy
Restore health and defense function
Decline in AIDS morbidity, hospitalization and mortality
Improve well-being
Improve the quality of life
Prolong survival of the patients with AIDS
Goals of Therapy
Suppression of viral replication to an undetectable level is the goal
of HAART. Effectiveness of the treatment is readily demonstrable by a
precipitous fall in plasma viral load and often a rise in CD4 count.
4. What kinds of antiretroviral
therapy are available in Hong Kong?
There are three classes of antiretroviral drugs
available in Hong Kong (Appendix I):
(I) Nucleoside/Nucleotide Reverse Transcriptase
Inhibitors (NRTI)
Action: HIV's enzyme called reverse transcriptase convert RNA to DNA.
NRTI block reverse transcription by providing faulty building blocks that
interrupt the process.
Currently available drugs in this class are:
1. Zidovudine |
(AZT) |
(Retrovir) |
2. Didanosine |
(ddI) |
(Videx) |
3. Didanosine EC |
(ddIEC) |
(Videx EC) |
4. Lamivudine |
(3TC) |
(Epivir) |
5. Zalcitabine |
(ddC) |
(Hivid) |
6. Stavudine |
(d4T) |
(Zerit) |
7. Combivir |
(CBV) |
|
8. Abacavir |
(ABC) |
(Ziagen) |
9. Tenofovir |
(TDF) |
(Viread) |
10. Trizivir |
(ABC+AZT+3TC) |
(II) Non-Nucleoside
Reverse Transcriptase Inhibitors (NNRTI)
Action: NNRTI stop HIV production by binding directly onto reverse transcriptase
and prevent the enzyme from converting RNA to DNA.
Currently available drugs in this class are:
1. Efavirenz |
(EFZ) |
(Sustiva) |
2. Nevirapine |
(NVP) |
(Viramune) |
(III) Protease Inhibitors
(PI)
Action : PI block the action of an enzyme, called Protease that cuts HIV
protein chains into specific proteins needed to assemble a new copy of
HIV. Therefore, PI prevent the cell from producing new HIV.
Currently available drugs in this class are:
| 1. Indinavir | (IDV) | (Crixivan) |
| 2. Saquinavir | (SQV) | (Hard gel-Invirase, Soft gel-Fortovase) |
| 3. Ritonavir | (RTV) | (Norvir) |
| 4. Nelfinavir | (NFV) | (Viracept) |
| 5. Kaletra | (LPV+RTV) |
5. When to consider
using antiretroviral therapy?
The doctor will consider using antiretroviral therapy when the infected
individual has suffered clinically or immunologically from the virus or
has at a heightened risk of disease progression. The following are the
indicators for treatment: *
- Low CD4 count
- High viral load level
- Signs of opportunistic infection
- Psychologically well prepared to comply with this long-term treatment in order to achieve the goal of therapy
6. Special attention
while taking antiretroviral drugs
Different drugs would have different precautions, e.g.:
- Some drugs work best when they are taken with food while some should be taken on an empty stomach.
- May need to increase water intake.
- Some kinds of food, drugs, Chinese medicines or alcohol should be avoided to prevent adverse reaction.
- Some drugs need to be stored in a refrigerator or
special container.
Thus, the infected individual should follow the instruction of health care providers when taking antiretroviral drugs.
7. Nine tips on successful drug taking
Commit to drug taking strongly
8. How to control over antiretroviral therapy?
Make a personal commitment to your therapy
Keep in close touch with your health care providers
Attend regular follow-up
9. How to know whether
treatment is working?
Health monitoring blood test:
CD4 count - reflect how strong immune system is
Viral load measurement - measure level of HIV in blood
In general, treatment is considered to be working if the viral load is
falling or remains low, and the CD4 level is rising or remains stable.
10. What is meant
by "undetectable" viral load?
Undetectable viral load means that HIV level is too low to be picked up
by the viral load test. HIV are still in the body and can transmit to
others through sexual and blood contact. Therefore, it is essential to
continue treatment and take precautions against its spread e.g. safer
sex.
11. The importance
of drug adherence
The most important element in the success of your anti-HIV treatment is
to strictly adhere to the drug regimen. Good drug adherence can prevent
treatment failure and the emergence of resistance. Poor drug adherence
will lead to the development of drug resistance, limiting the effectiveness
of therapy.
Thus, the most important thing you can do to stay healthy is always to
take your drugs in the right way and at the right time.
12. Degree of drug
adherence
The nurse counsellor usually calculates your degree of drug adherence
by:
13. Non-adherence
can lead to drug resistance
Drug resistance means the reduction of a drug's ability to work against
HIV. Resistance is thought to occur when its target mutates, changing
its structure so that the drug can no longer bind to work as well as it
used to.
Missing doses or taking even short "drug holidays" give the
virus change its form and multiply. When you start taking your drugs again,
they may not work as well. Thus, non-adherence to drug regimen can lead
to drug resistance.
Cross-resistance:
The mechanism by which HIV that has developed resistance to one drug may
also be resistant to other similar drugs.
DRUG RESISTANCE
Taking your drugs on time, every time is essential and has its reward:
- Lower or undetectable viral load result
- Higher CD4 count, increase/maintain immune function.
The best way to avoid resistance is to adhere to the regimen - EVERYDAY, EVERY TIME
14. Signs of treatment failure
- Increase viral load
- Decrease CD4 count
- Increase risk of disease progression
- Increase hospitalization and risk of death
Missing doses or taking the wrong doses can lead to drug resistance. You can quickly become resistant to antiretroviral drugs if you do not take them at the right time, in the right way and in the right dose. If drug failure is evident in terms of clinical, immunological, or virological deterioration, change of antiretroviral regimen is indicated.
15. Side effects
of antiretroviral therapy
Many side effects are temporary. If you encounter unpleasant side effects,
do not discontinue the drugs or alter the dosage by yourself. You should
discuss your problem with the health care providers to understand the
alternatives of the way and time of drug taking, so that a more appropriate
drug taking plan could be developed.
Transient side effects:
- Nausea/ vomiting
- Diarrhoea
- Allergy
- Headache
- Fatigue
- Fever
- Central Nervous System (CNS) symptoms (e.g. dizziness, insomnia, drowsiness, nightmares, inability to concentrate, etc.)
Potential long term side effects:
- Anaemia (low red blood cell count)
- Kidney stones
- Deranged liver function
- Peripheral neuropathy
- Pancreatitis
- Redistribution of fat (lipodystrophy)
- Metabolic problems (e.g. increase blood fats/ blood sugar)
- Neutropenia (an abnormal decrease in the number of neutrophils in the blood)
16. Managing side
effects
Side effects to antiretroviral drugs are common during the first few weeks
of treatment. However, these symptoms will often pass as your body gets
used to the drugs. You should report any unusual symptoms to your doctor/health
care providers. If necessary, your doctor will prescribe medications to
help you get over the initial period. The following is a quick reference
for managing side effects of antiretroviral drugs.
Managing side effects: A quick reference chart
| Diarrhoea |
|
Self
management:
Consult your doctor:
|
| Upset Stomach (Nausea, Vomiting, Poor Appetite) |
|
Self
management:
Consult your doctor:
|
| Feeling Tired (Fatigue) |
|
Self
management:
Consult your doctor:
|
| Dizziness, Confusion, and Sleeping Problems |
|
Self
management:
Consult your doctor:
|
| Headache |
|
Self
management:
Consult your doctor:
|
| Fat Problems (Lipodystrophy) |
|
Self
management:
Consult your doctor:
|
| Nerve Problems, Tingling Hands and Feet (Neuropathy) |
|
Self
management:
Consult your doctor:
|
| Liver Problems |
|
Self
management:
Consult your doctor:
|
| Metabolic Problems |
|
Self
management:
Consult your doctor:
|
| Bone Problems |
|
Self
management:
Consult your doctor:
|
17. The use of antiretroviral agents
for prophylaxis
Effectiveness of antiretroviral drugs is already
well-proven as prophylaxis to reduce the risk of HIV transmission in two
specific health care settings:
- Perinatal infection (mother to child transmission)
- Post occupational exposure prophylaxis
18. Conclusion
By using antiretroviral therapy and adopting good
drug adherence practice, you can stay a healthy life. Be relax, take nutritious
food, do regular exercise, join a support group and develop a hobby are
some smart ways to maintain good health and improve your quality of life.
|
Classes
of antiretroviral drugs (A) Nucleoside/Nucleotide Reverse Transcriptase Inhibitors (NRTI)
B) Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTI)
(C) Protease Inhibitors (PI)
Reference: |
|
Progress Sheet
|