A 42-year-old woman who has taken clonazepam daily for panic disorder for 6 years is brought to casualty drowsy after swallowing 20 of her tablets. She rouses to voice, with a respiratory rate of 14/min, SpO2 96% on room air and a normal ECG. The intern wants to give IV flumazenil to wake her. What is the main danger of doing so?

Precipitated withdrawal with seizures

Toxicology antidotes, pharmacovigilance and drugs in pregnancy

11 NEET-PG practice questions on Toxicology antidotes, pharmacovigilance and drugs in pregnancy, part of Pharmacology. The first 11 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Medium
A 24-year-old woman with juvenile myoclonic epilepsy is brought to casualty in Jaipur 4 hours after swallowing 30 tablets of sodium valproate 500 mg after a family quarrel. She is drowsy but protecting her airway, BP is 110/70 mmHg, and her blood ammonia is 160 µmol/L (normal below 50 µmol/L). Liver enzymes and bilirubin are normal. Which specific treatment should be started?
1. AIntravenous fomepizole
2. BIntravenous flumazenil
3. CIntravenous L-carnitine
4. DIntravenous acetylcysteine
Show answerHide answer
Answer: C · Intravenous L-carnitine
Valproate overdose causes CNS depression, and valproate-induced hyperammonaemia can cause encephalopathy even when liver function is normal. Valproate depletes carnitine, which carries long-chain fatty acids into mitochondria, and its metabolites impair the urea cycle, so ammonia rises. IV L-carnitine replaces carnitine and is advised in valproate overdose with hyperammonaemia, encephalopathy or liver injury, along with supportive care. Haemodialysis is considered for very high levels with coma or shock.
- A: Fomepizole blocks alcohol dehydrogenase in methanol and ethylene glycol poisoning.
- B: Flumazenil reverses benzodiazepines and may provoke seizures in a person with epilepsy.
- D: Acetylcysteine is the antidote for paracetamol poisoning.
Question 2 · Medium
A district hospital drug and therapeutics committee in Tamil Nadu is revising its formulary in line with the National List of Essential Medicines (NLEM). The pharmacologist presents four statements: 1. Medicines are chosen mainly because they are the cheapest available. 2. The essential medicines concept comes from WHO, which issued its first Model List in 1977. 3. Medicines on the NLEM are price-controlled by the NPPA under the Drugs (Prices Control) Order. 4. Medicines on the list are named by their generic names. Which statements are correct?
1. A2, 3 and 4 only
2. B2 and 3 only
3. C1, 2 and 4 only
4. D1 and 4 only
Show answerHide answer
Answer: A · 2, 3 and 4 only
Statements 2, 3 and 4 are correct. Essential medicines are those that meet the priority health needs of the population, and they are chosen for public health relevance, evidence of efficacy and safety, and comparative cost-effectiveness, not simply the lowest price. WHO published its first Model List of Essential Medicines in 1977, and India's NLEM, listed by generic name, forms the schedule of medicines whose ceiling prices the National Pharmaceutical Pricing Authority fixes under the Drugs (Prices Control) Order. Hospitals use the list to guide procurement and rational prescribing.
- B: Leaves out generic naming, which is correct.
- C: Includes cost alone as the basis for selection and leaves out price control.
- D: Includes cost alone and leaves out WHO's model list and price control.
Question 3 · Medium
A 42-year-old woman who has taken clonazepam daily for panic disorder for 6 years is brought to casualty drowsy after swallowing 20 of her tablets. She rouses to voice, with a respiratory rate of 14/min, SpO2 96% on room air and a normal ECG. The intern wants to give IV flumazenil to wake her. What is the main danger of doing so?
1. APrecipitated withdrawal with seizures
2. BSerotonin syndrome
3. CAcute dystonic reaction
4. DMalignant hyperthermia
Show answerHide answer
Answer: A · Precipitated withdrawal with seizures
Flumazenil is a competitive antagonist at the benzodiazepine site of the GABA-A receptor. In someone dependent on long-term benzodiazepines it can precipitate abrupt withdrawal with agitation and seizures, and it can unmask seizures when a proconvulsant such as a tricyclic antidepressant has also been taken. A pure benzodiazepine overdose with protected breathing rarely kills, so supportive care and observation are enough here. Flumazenil is mainly used to reverse sedation given for procedures in benzodiazepine-naive patients, and because it is short-acting, sedation may return.
- B: Serotonin syndrome follows combinations of serotonergic drugs.
- C: Acute dystonia follows dopamine blockers such as metoclopramide.
- D: Malignant hyperthermia follows volatile anaesthetics or succinylcholine.
Question 4 · Medium
A 4-year-old girl whose family recycles old car batteries at home in a Delhi slum has abdominal colic, constipation, irritability and poor appetite. Hb is 8.9 g/dL with microcytic red cells showing basophilic stippling, and her blood lead level is 58 µg/dL. She is alert with no signs of encephalopathy. Besides removing her from exposure, which treatment is most appropriate?
1. AOral deferiprone
2. BOral succimer (DMSA)
3. CIntravenous desferrioxamine
4. DRepeat blood lead in 3 months
Show answerHide answer
Answer: B · Oral succimer (DMSA)
Lead inhibits delta-aminolevulinic acid dehydratase and ferrochelatase, causing anaemia with basophilic stippling, and damages the developing brain even at low levels. A child with a blood lead of 45-69 µg/dL and no encephalopathy is chelated with oral succimer (dimercaptosuccinic acid), whereas encephalopathy or a level of 70 µg/dL or more calls for dimercaprol followed by calcium disodium EDTA in hospital. Removing the source, correcting iron deficiency and testing her siblings matter as much as the chelator.
- A: Deferiprone is an oral iron chelator, not a lead antidote.
- C: Desferrioxamine chelates iron and aluminium, not lead.
- D: A level of 58 µg/dL with symptoms needs chelation now, not observation.
Question 5 · Medium
A 25-year-old woman at 20 weeks of pregnancy has a mucopurulent cervical discharge at her antenatal visit, and a nucleic acid amplification test on the cervical swab is positive for Chlamydia trachomatis. Which drug is preferred for her?
1. AMetronidazole
2. BLevofloxacin
3. CDoxycycline
4. DAzithromycin
Show answerHide answer
Answer: D · Azithromycin
Azithromycin as a single oral dose is the preferred treatment for chlamydial infection in pregnancy; amoxicillin is an alternative. Tetracyclines such as doxycycline are avoided because they cross the placenta and bind calcium in developing teeth and bones, causing permanent yellow-brown staining, enamel hypoplasia and impaired bone growth. Fluoroquinolones are also avoided in pregnancy. Her partner must be treated, and a test of cure is advised in pregnancy because untreated infection can cause neonatal conjunctivitis and pneumonia.
- A: Metronidazole treats trichomonas and bacterial vaginosis, not chlamydia.
- B: Fluoroquinolones are avoided in pregnancy.
- C: Doxycycline is avoided in pregnancy because it stains fetal teeth and affects bone.
Question 6 · Easy
Thalidomide is still prescribed in India for erythema nodosum leprosum and multiple myeloma, under strict pregnancy prevention. Taken in early pregnancy, which characteristic birth defect does it cause?
1. ACleft lip and palate
2. BEbstein anomaly
3. CSpina bifida
4. DPhocomelia
Answer and explanation in LearnFree account
Question 7 · Hard
A 34-year-old man is pulled out of a fire in a closed godown full of plastic goods and foam furniture. He is confused and then has a seizure. BP is 80/50 mmHg, SpO2 on the pulse oximeter is 97% on high-flow oxygen, serum lactate is 11 mmol/L and carboxyhaemoglobin is 18%. Besides 100% oxygen, which antidote is most appropriate?
1. AInhaled amyl nitrite
2. BIntravenous sodium nitrite
3. CIntravenous methylene blue
4. DIntravenous hydroxocobalamin
Answer and explanation in LearnFree account
Question 8 · Easy
A junior resident in a medical college in Lucknow sees a man who developed a widespread rash with fever two weeks after starting carbamazepine. She fills in the Suspected Adverse Drug Reaction Reporting Form and sends it to the college's ADR monitoring centre. Under the Pharmacovigilance Programme of India, which body houses the National Coordination Centre?
1. ANational Pharmaceutical Pricing Authority
2. BIndian Council of Medical Research
3. CNational Centre for Disease Control
4. DIndian Pharmacopoeia Commission
Answer and explanation in LearnFree account
Question 9 · Medium
A 19-year-old girl on treatment for pulmonary TB is brought to casualty an hour after swallowing 25 tablets of isoniazid 300 mg after a quarrel. She has had three generalised seizures that did not stop with two doses of IV lorazepam. ABG: pH 7.06, HCO3- 8 mmol/L, lactate 9 mmol/L. Which specific antidote should be given?
1. AIntravenous pyridoxine
2. BIntravenous thiamine
3. CIntravenous phenytoin
4. DIntravenous flumazenil
Answer and explanation in LearnFree account
Question 10 · Hard
A 30-year-old man develops a generalised itchy maculopapular rash on the fifth day of amoxicillin for sinusitis. He takes no other medicine, has no fever, lymph nodes or other features of a viral illness, and has had no previous drug reactions. The rash fades within a week of stopping amoxicillin, and he is not given the drug again. Using the WHO-UMC causality system, how should this reaction be graded when it is reported to PvPI?
1. AUnlikely
2. BCertain
3. CProbable/likely
4. DPossible
Answer and explanation in LearnFree account
Question 11 · Medium
A 30-year-old paddy farmer in Tamil Nadu is bitten on the foot by a snake that his companions identify as a cobra. Two hours later he has bilateral ptosis, difficulty swallowing and a weak voice, with no bleeding and a normal 20-minute whole blood clotting test. Polyvalent anti-snake venom has been started. Which drug is given with it to improve neuromuscular transmission?
1. ANeostigmine with atropine
2. BIntravenous magnesium sulphate
3. CPralidoxime with atropine
4. DIntravenous calcium gluconate
Answer and explanation in LearnFree account

Toxicology antidotes, pharmacovigilance and drugs in pregnancy

A 25-year-old woman at 20 weeks of pregnancy has a mucopurulent cervical discharge at her antenatal visit, and a nucleic acid amplification test on the cervical swab is positive for Chlamydia trachomatis. Which drug is preferred for her?

Thalidomide is still prescribed in India for erythema nodosum leprosum and multiple myeloma, under strict pregnancy prevention. Taken in early pregnancy, which characteristic birth defect does it cause?