Tox: antibiotics and ARVs

Question 1

Primary indication for isoniazid

Answer 1

Tuberculosis

Question 2

Complications from chronic isoniazid use

Answer 2

Peripheral neuropathy, hepatitis, drug induced SLE.

Question 3

Main concern/complication with acute isoniazid toxicity

Answer 3

Seizures refractory to benzos

Question 4

MOA of isoniazid toxicity

Answer 4

Reduction in B6 in brain -> Reduced GABA production and increased glutamate -> predisposition to seizures

Question 5

Signs/symptoms isoniazid toxicity

Answer 5

N/v, slurred speech, ataxia, AMS, seizures, status epilepticus, AGMA

Question 6

Antidote for isoniazid

Answer 6

Vitamin B6 (pyridoxine): replenishes B6 stores which helps replete GABA (give 5g IV)

Question 7

Complication from chronic large doses of pyridoxine

Answer 7

peripheral neuropathy

Question 8

Tx of isoniazid toxicity

Answer 8

Supportive care, AC If early presentation.

Benzos/barbiturates for status until B6/pyridoxine available

Question 9

Types of HAART

Answer 9

1) Reverse transcriptase inhibitors (nucleoside/non-nuceloside)
2) Integrase inhibitors
3) Protease inhibitors
4) Fusion inhibitors

Question 10

Examples of reverse transcriptase inhibitors

Answer 10

ddI (didanosine), d4T (stavudine), 3TC (lamivudine)

Question 11

Mxn of antriretroviral toxicity

Answer 11

Mitochondrial toxicity -> lactic acidosis, hepatotoxicity, pancreatitis

Question 12

Mgmt of antiretroviral toxicity

Answer 12

1) Discontinue drug, supportive care.

2) If severe lactic acidosis -> HCO3, HD or CRRT