STD Flashcards
Management of uncomplicated Gonorrhea (1st Line)
Normal weight (<150kg) = ?
Severely obese (>= 150kg) = ?
IM Ceftriaxone 500mg ONCE
IM Ceftriaxone 1g ONCE
If Chlamydial Infection is not excluded -> PO Doxycycline 100mg BD for 7d
Management of uncomplicated Gonorrhea (2nd Line)
IM Gentamicin 240mg ONCE + PO Azithromycin 2g ONCE (Long intracellular half life)
Management of Chlamydial Infection (1st Line)
PO Doxycycline 100mg BD for 7d
Management of Chlamydial Infection (If adherence is an issue)
PO Azithromycin 1g ONCE (Long intracellular half life)
Management of Chlamydial Infection (2nd Line)
PO Levofloxacin 500mg OD for 7d
Test of cure for Chlamydial Infection required?
NO (Low risk of resistance)
Test of cure for Gonorrhea required?
YES (Have chance of resistance)
Different stages of Syphilis (Treponema Palladium)
Primary (Localised - painless ulcer/ painful multiple lesions)
Secondary (More systemic - skin rash, alopecia, lymph node involvement)
Latent (Asymptomatic)
Tertiary (More systemic - lesions of joints, heart and aortic involvement)
Neurosyphilis (Bacteria gone into the CSF)
Management of Syphilis W/O Penicillin Allergy (Primary/Secondary/Latent < 1yr)
IM Benzathine Penicillin G 2.4MU ONCE
Management of Syphilis W/ Penicillin Allergy (Primary/Secondary/Latent < 1yr)
PO Doxycycline 100mg BD for 14 days
Management of Syphilis W/O Penicillin Allergy (Latent >1yr/Unknown duration/Tertiary)
IM Benzathine Penicillin G 2.4MU Once a week for 3 doses
Management of Syphilis W/ Penicillin Allergy (Latent >1yr/Unknown duration/Tertiary)
PO Doxycycline 100mg BD for 28 days
Management of Neurosyphilis W/O Penicillin Allergy
IV Crystalline Penicillin G 3-4MU q4hr over 10-14d
OR
IV Crystalline Penicillin G 18-24MU q24hr as continuous infusion over 10-14d
Management of Neurosyphilis W Penicillin Allergy
IV/IM Ceftriaxone 2g OD for 10-14d
Monitor for cure for Syphilis?
YES
What to monitor for cure of Syphilis (primary/secondary/latent)
Conduct non-treponemal test (VDRL/RPR) at 3, 6, 12, 18, 24 months after starting treatment.
VDRL & RPR titre should reduce by 4 fold (e.g. from 1:64 to 1:16)
If sx still present/failure to achieve titre reduction -> reevaluate syphilis status and treat accordingly
What to monitor for cure of Neurosyphilis
CSF every 6 months until it comes back to normal
Can genital herpes be eradicated?
NO. The HSV virus will stay dormant in the nerve ganglia cells.
What virus most commonly cause genital herpes
HSV-2 Mainly
HSV-1 (cause cold sores) possible due to oral sex
Genital herpes can spread even when a person is asymptomatic
YES
Are symptoms for genital herpes self-limiting
Vesicles develop over 7-10d and health in 2-4 wks
Management of 1st episode for HSV (Acyclovir)
PO Acyclovir 400mg TDS for 7-10d
More severe (immunocompromised that requires hospitalisation),
IV Acyclovir 5-10mg/kg q8hr for 2-7d followed by the oral regimen for a total of 10d
Management of 1st episode for HSV (Valacyclovir)
PO Valacyclovir 1g BD for 7-10d (Greater F than Acyclovir)
Mechanism of action of Acyclovir
Inhibit viral DNA polymerase –> inhibit DNA synthesis and replication
What are the typical symptoms before onset of recurrent flare (HIV)
Prodrome - Mild itching, burning, tingling sensation
Adverse drug reaction antiviral therapy?
GI Side effect. N/V/D. Kidney injury (recrystallisation of the drug which damages kidney tubules if not adequately hydrated)
Benefits of chronic suppressive therapy for recurrent outbreaks
- Reduces the frequency of recurrences
- No symptomatic outbreaks
- Decrease the risk of transmission
Benefit is the most for immunocompromised HIV patients!
Chronic suppressive therapy for recurrent outbreaks (Regimen)
Lower dose compared to the initial outbreak:
1. PO Acyclovir 400mg BD
2. PO Valacyclovir 500mg OD (For < 10 outbreaks per yr)
3. PO Valacyclovir 1g OD (For >= 10 outbreaks per yr)
Episodic therapy during recurrent outbreaks
Lower dose compared to the initial outbreak:
1. PO Acyclovir 800mg BD for 5d
2. PO Acyclovir 800mg TDS for 2d
3. PO Valacyclovir 500mg BD for 3d
4. PO Valacyclovir 1g OD for 5d
Counselling for HSV
- Pre-empt the patient (natural course of disease + increased risk of HIV)
- Reduce transmission
- Transmission can occur even if they are asymptomatic
- Encourage CST
- Encourage condom use
- Encourage abstinence from sex when symptomatic
When does a person has AIDS?
CD4 T cell count < 200mm^3
OR
Uncommon infections that affect the CNS, eyes, lungs (pneumocystic pneumonia), skin and GI tract & Cancer (Lymphoma, Kaposi Sarcoma)
What is defined as a response to therapy for HIV? (CD4)
CD4 count increase by 50-150mm^3 in 1st year of therapy
The utility of CD4 count as a surrogate marker?
- Indicator of immune function
- Progression of disease
- Response to therapy
- Starting and discontinuing prophylactic treatment for opportunistic infection (e.g. pneumocystis pneumonia)
Effective regimen decreases viral load in ___ weeks
8-24 weeks
When to measure CD4 count? (HINT: Need time to restore back the CD4 count)
Baseline
Every 3 to 6 months after treatment initiation
Every 12 months after an adequate response
When to measure viral load?
Baseline
Within 2 - 4 wks (not later than 8 weeks) after treatment initiation or
modification, thereafter, every 4 to 8 weeks until viral load
suppressed
When to start ART?
As soon as the patient is diagnosed with HIV! To reduce morbidity, mortality & transmission
1st line initiation therapy for HIV
2 NRTI + 1 INSTI
- Tenofovir + Emtricitabine + Bictegravir
- Tenofovir + Emtricitabine + Dolutegravir
- Abacavir + Lamivudine + Dolutegravir
Alternative initiation therapy for HIV
Emtricitabine + dolutegravir
NOT for individuals with:
- High viral load (HIV RNA >500,000 copies/mL) OR
- HBV coinfection OR
- Resistance strains
List Nucleoside Reverse Transcriptase Inhibitors (NRTI)
No fix pattern
Tenofovir, Emtricitabine, Abacavir, Lamivudine, Zidovudine
List Integrase Strand Transfer Inhibitor (INSTI)
(-Tegravir)
Bictegravir, Dolutegravir, Raltegravir, Elvitegravir
List Protease Inhibitors (PI)
(-Navir)
Ritonavir, Lopinavir, Atazanavir, Darunavir, Fosamprenavir
How is NRTI eliminated?
Renal elimination, little concerns for drug interactions (except abacavir)
What are the major ADRs for NRTI?
For All:
1. Mitochondria toxicities (Zidovudine highest risk) - Lactic acidosis & hepatic steatosis & lipoatrophy
2. GI distrubance: N/V/D
Individual agent:
1. Lamivudine & Emtricitabine – minimal toxicity
2. Tenofovir: – Renal impairment, decrease in bone mineral density
3. Abacavir: Hypersensitivity reaction in patients with HLA-B*5701. Concern for association with MI – not be used in high cardiovascular risk patients.
4. Zidovudine – bone marrow suppression –> anaemia or neutropenia.
What are the major ADRs for INSTI?
For All:
1. Weight gain, N/V/D, headache
2. Rare depression, and suicidal ideation in psychiatric patients
Individual agent:
1. Bic & Dolu: Inc SCr
2. Raltegravir- pyrexia, creatine kinase elevation (rhabdomyolysis)
What are the major DDIs for INSTI?
Bioavailability lowered by concurrent administration of polyvalent
cations
CYP 3A4 substrates (Bictegravir, dolutegravir and elvitegravir)
What is the main advantage of using Non-nucleoside Reverse Transcriptase Inhibitors?
Long half-lives
What is the main disadvantage of using Non-nucleoside Reverse Transcriptase Inhibitors?
- Low genetic barrier to resistance
- Skin rash, SJS (R < E)
- Potential for CYP450 drug interactions (some are inducers
and some are inhibitors) - QTc prolongation
What are the major ADRs for NNRTI?
- Metabolic condition (worsen HLD)
- Neuropsychiatric (dizziness, depression, insomnia, abnormal dreams, hallucination)
List Non-nucleoside Reverse Transcriptase Inhibitors (NNRTI)
Efavirenz, Rilpivirine (preferred)
The role of Ritonavir
PK Enhancer
Potent CYP3A4, 2D6 inhibitor; frequently combined with other PI to “boost” their levels (eg Lopinavir/ritonavir)
What are the major ADRs for PI?
- Metabolic complications (dyslipidemia, insulin resistance) - Atazanavir lesser
- GI side effects (N/V/D)
- Liver toxicity (especially with chronic hepatitis B or C)
- CYP3A4 inhibitors and substrates: potential for DI
- Morphologic Complications: Fat maldistribution (Lipohypertrophy)
- Increased risk of osteopenia/osteoporosis
What must be done before the use of CCR5 inhibitor?
- Need co-receptor tropism assay before initiation
- Must be CCR5 predominant to use maraviroc (not to use if
CXCR4 or dual/mixed tropism)
