Drugs for TB, leprosy and mycobacterium avium complex infection

Isoniazid (INH)

Primary agent for treatment and prophylaxis of TB

Isoniazid (INH) MOA

Inhibits synthesis mycolic acid, a component needed for mycobacterial cell walls

• Bactericidal to actively dividing bacteria

• Bacteriostatic to dormant bacteria

Isoniazid (INH) adverse effects

Hepatotoxicity/liver injury → multilobular necrosis

Neuropathy & pyridoxine (B6) deficiency

Optic neuritis and visual disturbances

Isoniazid (INH) nursing considerations

Do not take with antacids due to decreased absorption

Educate on and monitor for s/s hepatitis

Monitor liver enzymes

Educate on s/s peripheral neuropathy; may be reversible with vitamin B6

Report visual changes immediately

Risk for non-adherence due to long term treatment duration

Rifampin (Rifandin)

Rifamycin class abx; Primary agent for treatment and prophylaxis of TB

Rifampin (Rifandin) MOA

Inhibits DNA-dependent RNA polymerase to suppress RNA synthesis and protein synthesis

Rifampin (Rifandin) indications

Drug of choice (DOC) for TB in combination with at least one other agent due to resistance

Leprosy (once/month dosing)

MAC (with ethambutol and macrolide)

Rifampin (Rifandin) adverse effects

Hepatotoxicity

Body fluid red-orange-brown discoloration

Hematologic disorders

Effects r/t accelerated metabolism of oral contraceptives, warfarin, PI & NNRTI

Rifampin (Rifandin) nursing considerations

Educate on and monitor for s/s hepatitis

Monitor liver enzymes and complete blood count

Education on fluid discoloration

Child-bearing age female patients need additional birth control

Pyrazinamide

First-line agent used in combo therapy for TB

Pyrazinamide MOA

Medication is metabolized to pyrazinoic acid to lower pH

Inhibits m. tuberculosis enzyme, fatty acid synthetase I

Pyrazinamide indications

Part of multi-drug regimen for active TB

Pyrazinamide adverse effects

Hepatotoxicity, particularly with concurrent TB agent use

Hyperuricemia → gouty arthritis

Pyrazinamide nursing considerations

Educate on and monitor for s/s hepatitis

Monitor liver enzymes and serum uric acid levels

Report any gout-like s/s; use NSAID PRN

Ethambutol (Myambutol)

First-line agent used in combo therapy for TB; also used for MAC

Ethambutol (Myambutol) MOA

Promotes a bacteriostatic action by inhibiting arabinosyl transferase resulting in impaired mycobacterial cell wall synthesis

Ethambutol (Myambutol) adverse effects

GI tract disturbances

Optic neuritis, resulting in blurred vision, constriction of visual field, and disturbance of color discrimination

Possible hepatotoxicity; higher risk with multi-drug TB regimen

Ethambutol (Myambutol) nursing considerations

Educate on and monitor for s/s hepatitis

Monitor liver enzymes

Take with food as needed to minimize GI upset

Monitor for acute visual changes