Antitubercular drugs

Antitubercular drugs

Drug monograph · NCLEX study reference
Trade names	INH
Therapeutic class	Antitubercular
Pharmacologic class	Mycobacterial agents (RIPE regimen)
Onset / peak / duration	Prolonged therapy (months); often once daily.
Half-life / level	Varies; no routine level.
Routes	PO (oral)
High-alert (ISMP)	No
Black box warning	Yes (see Safety)
Antidote / reversal	Pyridoxine for isoniazid neuropathy and overdose; supportive care.
Pregnancy / lactation	Treated under specialist care; isoniazid with pyridoxine commonly used.

Nursing pharmacology study reference (NCLEX-style monograph). Numeric values are standard teaching ranges for study and must be verified against current manufacturer labeling before clinical use. This is educational content, not prescribing guidance.

Antitubercular drugs (brand name INH) — Antitubercular; Mycobacterial agents (RIPE regimen).

Identification

• Therapeutic class: Antitubercular.
• Pharmacologic class: Mycobacterial agents (RIPE regimen).

Pharmacology

• Mechanism of action: Each disrupts mycobacterial growth by a different mechanism; used in combination to prevent resistance.
• Onset / peak / duration: Prolonged therapy (months); often once daily.
• Half-life / therapeutic level: Varies; no routine level.

Clinical use

• Indications: Active and latent tuberculosis (isoniazid for latent).
• Usual dose, route, frequency: PO daily, often as combination therapy; directly observed therapy is common.
• Maximum dose / adjustments: Adjust isoniazid and others by hepatic and renal function; add pyridoxine (B6) with isoniazid to prevent neuropathy.

Safety

• Contraindications: Active liver disease (isoniazid, pyrazinamide), optic neuritis (ethambutol).
• Black box warning: Isoniazid carries a boxed warning for severe and sometimes fatal hepatitis; monitor liver function.
• Interactions: Rifampin is a strong CYP inducer (lowers oral contraceptives, warfarin, many drugs); isoniazid with alcohol (hepatotoxicity), tyramine and histamine foods; antacids reduce isoniazid absorption.
• Pregnancy / lactation: Treated under specialist care; isoniazid with pyridoxine commonly used.
• High-alert: No.

Adverse effects

• Common side effects: GI upset, rifampin causes harmless orange-red discoloration of urine, sweat, and tears (stains contact lenses).
• Serious effects to report: Hepatotoxicity (all), isoniazid peripheral neuropathy, ethambutol optic neuritis (color vision and acuity changes), pyrazinamide hyperuricemia and gout.
• Antidote / reversal: Pyridoxine for isoniazid neuropathy and overdose; supportive care.

Nursing process

• Assessment before administration: Baseline LFTs, vision (ethambutol), uric acid, alcohol use, neuro baseline.
• Interventions during therapy: Stress adherence for the full course; give isoniazid with pyridoxine; monitor liver function.
• Monitor: LFTs, vision (ethambutol), uric acid (pyrazinamide), sputum conversion, neuro status.
• Evaluation / expected outcome: Negative cultures and cure without toxicity.

Patient teaching

• Patient teaching: Take the full months-long course; rifampin harmlessly turns body fluids orange; use backup contraception; report vision changes; avoid alcohol; report yellowing of skin.
• Notify provider if: Yellowing of skin or eyes, dark urine, numbness, vision or color changes, joint pain.
• Administration tips: Isoniazid on an empty stomach with pyridoxine; emphasize adherence.