What is the Philippine guideline for tuberculosis (TB) treatment?

Philippine Guideline for Tuberculosis Treatment

I was unable to locate specific Philippine national tuberculosis treatment guidelines in the provided evidence. However, I can provide the internationally recognized standard treatment protocols that are typically adopted by national programs, including the Philippines, which follows WHO recommendations and has implemented DOTS (Directly Observed Treatment, Short-course) through its National TB Control Programme.

Standard Drug-Susceptible TB Treatment

The recommended first-line treatment is a 6-month regimen consisting of isoniazid, rifampin, pyrazinamide, and ethambutol for the first 2 months (intensive phase), followed by isoniazid and rifampin for 4 months (continuation phase). 1, 2

Intensive Phase (First 2 Months)

• Daily administration of four drugs: isoniazid, rifampin, pyrazinamide, and ethambutol 1, 2
• All doses should be completed within 3 months 1
• Ethambutol should be included until drug susceptibility results are available, unless primary isoniazid resistance is less than 4% in the community 2

Continuation Phase (Next 4 Months)

• Daily isoniazid and rifampin 1, 2
• Thrice-weekly dosing is acceptable as an alternative 1
• All continuation phase doses should be completed within 6 months, so the entire 6-month regimen is finished within 9 months 1

Treatment Administration

• Directly observed therapy (DOT) is strongly recommended for all patients to ensure adherence 1, 3
• The Philippine DOTS program, implemented through the Revised National TB Control Programme, uses thrice-weekly higher-dose intermittent therapy (2E₃H₃R₃Z₃, 4H₃R₃) 4
• Fixed-dose combinations are recommended to minimize selective drug intake and improve adherence 4

Drug-Resistant TB Treatment

Isoniazid-Resistant TB

Add a later-generation fluoroquinolone (levofloxacin or moxifloxacin) to a 6-month regimen of daily rifampin, ethambutol, and pyrazinamide 5, 1

• Pyrazinamide duration can be shortened to 2 months in selected situations (noncavitary, lower burden disease, or pyrazinamide toxicity) 5

Multidrug-Resistant TB (MDR-TB)

For MDR-TB with confirmed susceptibility, the 6-month BPaLM regimen (bedaquiline, pretomanid, linezolid, moxifloxacin) is recommended 6

For individualized longer regimens when BPaLM is not suitable:

• Use at least 5 drugs in the intensive phase and 4 drugs in the continuation phase 5
• Include a later-generation fluoroquinolone (levofloxacin or moxifloxacin) - strong recommendation 5
• Include bedaquiline - strong recommendation 5
• Consider including linezolid, clofazimine, and cycloserine 5, 6
• Intensive phase duration: 5-7 months after culture conversion 5
• Total treatment duration: 15-21 months after culture conversion 5

Avoid using kanamycin, capreomycin, macrolides (azithromycin/clarithromycin), and amoxicillin-clavulanate (except with carbapenems) 5

Special Populations

HIV Co-infection

• Use the same standard 6-month regimen, but extend treatment to at least 9 months and for at least 6 months beyond culture conversion 6, 3
• Monitor clinical and bacteriologic response closely; prolong therapy if response is slow or suboptimal 2
• Rifampin interactions with antiretroviral therapy require careful management, particularly with protease inhibitors and NNRTIs 4

Pregnancy

• All first-line drugs (rifampin, isoniazid, ethambutol, pyrazinamide) can be used safely during pregnancy 4
• Streptomycin should be avoided due to fetal ototoxicity 4
• Prophylactic pyridoxine 10 mg/day is recommended 4

Diabetes Mellitus

• Use the same standard regimen with strict blood glucose control 4
• Oral hypoglycemic doses may need adjustment due to rifampin interaction 4
• Prophylactic pyridoxine is indicated 4

Renal Failure

• Adjust doses of streptomycin, ethambutol, and isoniazid according to creatinine clearance 4
• In acute renal failure, give ethambutol 8 hours before hemodialysis 4

Extrapulmonary TB (Including Intestinal TB)

• Use the same 6-month standard regimen for most extrapulmonary sites 3, 2
• Extend treatment to 12 months for TB meningitis, miliary TB, and bone/joint TB in children 2
• Extend to 9 months for spinal TB with neurological involvement 7

Treatment Interruptions

During Intensive Phase

• If interruption <14 days: Continue to complete planned doses within 3 months 1
• If interruption ≥14 days: Restart treatment from the beginning 1

During Continuation Phase

• If ≥80% doses completed and initial sputum AFB smear negative: Continue until all doses completed 1
• If <80% doses completed and lapse ≥3 months: Restart from the beginning 1

Monitoring and Follow-up

• Monthly sputum cultures until conversion, then less frequently 1, 6
• Drug susceptibility testing on the first isolate from all patients 1
• Regular clinical assessment for symptom improvement 1, 3
• Never add a single drug to a failing regimen - this leads to acquired resistance 1

Common Pitfalls

• Inadequate adherence is the primary cause of treatment failure and acquired drug resistance 1, 8
• The Philippines has documented high rates of drug resistance (80% in one Manila study), with 26% resistant to one drug and 54% resistant to two or more drugs 8
• Most MDR-TB is acquired due to poor chemotherapy rather than primary transmission 4
• Laboratory errors in drug susceptibility testing can lead to misdiagnosis of MDR-TB 4
• Consultation with a TB expert is strongly recommended for all drug-resistant cases 5, 4