Which of the following molecules contains double bond?
A)CH₃
B)CNH
C) C₂H₂
D)C₂H₄
A)CH₃
B)CNH
C) C₂H₂
D)C₂H₄
The molecule that contains a double bond is: D) C₂H₄ (ethylene)
This molecule is an alkene. To satisfy the valency of carbon (which needs four bonds), the two carbon atoms must share two pairs of electrons, forming a double bond (C=C).
Quick breakdown:
✖CH₃ → only single bonds
✖CNH (HCN) → contains a triple bond (C≡N)
✖C₂H₂ (acetylene) → contains a triple bond (C≡C)
✔C₂H₄ (ethylene) → contains a double bond (C=C)
Which of the following is a potential side effect of using chlorpromazine in an elderly person?
A) dyskinesia
B) constipation
C) urinary retention
D) tardive dyskinesia
Actually, this is a bit of a "trick" question because all four options are potential side effects of chlorpromazine. However, if you are looking for the most significant or specific risks associated with long-term use or the physiology of an elderly patient, the answer is usually D) Tardive dyskinesia - a late-onset, often irreversible extrapyramidal side effect characterized by involuntary movements (lip smacking, tongue protrusion, facial grimacing).
Side effects of Chlorpromazine:
1. Extrapyramidal Symptoms (EPS):
Chlorpromazine is a first-generation (typical) antipsychotic that works by blocking dopamine (D₂) receptors. This can lead to movement disorders:
↪Dyskinesia (A): General involuntary movements that can occur shortly after starting the medication.
↪Tardive Dyskinesia (D): This is the most serious long-term side effect. It involves repetitive, involuntary movements (like grimacing or eye blinking). The elderly are at a significantly higher risk for developing TD, and it is often irreversible.
2. Anticholinergic Effects:
Chlorpromazine also blocks acetylcholine receptors, which leads to "drying out" the body. While common in all patients, these are particularly dangerous for the elderly:
↪Constipation (B): Can lead to bowel obstructions in older patients with slower metabolisms.
↪Urinary Retention (C): Can cause significant distress and UTIs, especially in elderly men with enlarged prostates.
Why "D" is often the focused answer:
In a clinical or testing context, Tardive Dyskinesia is emphasized because:
*Risk Factor: Age is the primary risk factor for TD.
*Severity: Unlike constipation or temporary dyskinesia, TD can become a permanent neurological condition.
*Monitoring: Doctors must perform regular "AIMS" (Abnormal Involuntary Movement Scale) tests on elderly patients using this drug to catch TD early.
Note: Chlorpromazine also carries a "Black Box Warning" for elderly patients with dementia-related psychosis, as it increases the risk of death, often due to cardiovascular issues or infections like pneumonia.
📌 Exam pearl: Elderly + typical antipsychotic + long-term use = tardive dyskinesia
Drug X has an infusion rate of 0.95 mg/kg/hr. Which of the following is the amount of drug X (in mg) needed for a 12-hr infusion if patient weight is 70 kg?
A) 66.5 mg
B) 84 mg
C) 665 mg
A) 66.5 mg
B) 84 mg
C) 665 mg
D) 798 mg
Let’s calculate it step by step:
Infusion rate: 0.95 mg/kg/hr
Time duration: 12hrs
Patient weight: 70 kg
The formula is:
➡️ Dose per hour: 0.95 × 70 = 66.5 mg/hr
➡️ For 12 hours: 66.5 × 12 = 798 mg
✅ Correct answer: D) 798 mg
Quick exam tip:
Always multiply rate × weight × time (in that order) to avoid silly mistakes.
A 6-year-old child weighing 28 kg came to the clinic with viral infection. The physician prescribed acyclovir at a dose of 20 mg/kg four times a day. Acyclovir is available as 200 mg/5 ml oral suspension.
How many milliliters would be administered per day?A) 10
B) 14
C)44
D)56
Given:
Weight = 28 kg
Dose = 20 mg/kg per dose
Frequency = 4 times/day
Suspension strength = 200 mg / 5 mL
To determine the total volume of acyclovir administered per day, follow these steps:
Calculate the dose per administration (in mg):
Calculate the total daily dose (in mg):The physician prescribed the dose four times a day:
Convert the total daily dose from mg to ml:
The concentration of the oral suspension is 200mg/5mL.
Conclusion: The total amount administered per day is 56 ml.
Correct Option: D) 56
A patient is to receive one mg of hydromorphone hydrochloride injection for pain. Hydromorphone hydrochloride is available as 500 mg in a 50 ml vial. How many milliliters would be injected?
A)0.1
B) 0.5
C) 1.0
D) 2.0
Given:
Required dose = 1 mg
Available strength = 500 mg in 50 mL
1️⃣ Find concentration
2️⃣ Calculate volume needed for 1 mg
✅ Correct answer: A) 0.1 mL
💡 Exam tip:
Always reduce to mg per mL first — it makes these questions super fast.
How long does it take for the body to remove 99% of the drug by first order elimination process after a single dose?
A) 2 half-lives
B) 4 half-lives
C) 7 half-lives
D) 10 half-lives
In a first-order elimination process, a constant percentage of the drug is removed from the body per unit of time (the half-life). To find out how long it takes to remove 99% of the drug, we look at how much remains after each half-life.
After each half-life (t1/2), the concentration of the drug is reduced by 50%:
1 half-life: 50% remains (50% removed)
2 half-lives: 25% remains (75% removed)
3 half-lives: 12.5% remains (87.5% removed)
4 half-lives: 6.25% remains (93.75% removed)
5 half-lives: 3.125% remains (96.875% removed)
6 half-lives: 1.56% remains (98.44% removed)
7 half-lives: 0.78% remains (~99.2% removed)
As shown above, by the end of the 7th half-life, less than 1% of the drug remains in the system. In clinical pharmacokinetics, it is generally accepted that:
👉4 to 5 half-lives are required to reach steady state or to consider a drug "clinically" cleared (about 94-97% removed).
👉~6.64 half-lives are mathematically required to reach exactly 99% clearance.
Since 6.64 rounds up to the next whole interval provided in clinical scenarios, 7 half-lives is the standard answer for 99% clearance.
Correct Option: C) 7 half-lives
To read more such exam questions with explanation visit the blog or click on Prometric Exams.
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