---

Ampoule (Left)

• Structure: Sealed glass container with a narrow neck that is snapped/broken open to access the contents
• Closure: No stopper — the glass neck itself is the seal (broken at a colored or scored ring)
• Contents: Single-use only; entire volume must be used once opened
• Sterility: Cannot be re-entered after opening — any unused portion is discarded
• Volume: Typically small (1–10 mL)
• Risk: Risk of glass particle contamination when snapping the neck; requires filter needle
• Examples: Morphine, epinephrine, atropine, many contrast agents

---

Vial (Right)

• Structure: Glass bottle sealed with a rubber stopper crimped under an aluminum cap
• Closure: Rubber septum — accessed with a needle without breaking the container
• Contents: Can be single-dose or multi-dose
• Sterility: Multi-dose vials contain preservatives to maintain sterility after repeated punctures (single-dose vials do not)
• Volume: Wide range (1 mL to several hundred mL)
• Risk: Risk of microbial contamination with multi-dose vials if not handled properly; also risk of coring (rubber fragments entering the solution)
• Examples: Insulin, vaccines, antibiotics, heparin

---

Key Comparison Table

---

---

What You're Seeing

• The green seed capsules have been scored/incised with shallow cuts
• The white milky latex seeping out and drying into droplets is raw opium
• When dried and collected, this latex becomes the source of all natural opioids

---

Pharmacological Significance

---

Opioid Derivatives (From This Source)

Raw Opium Latex
      │
      ├── Morphine ──────→ Heroin (diacetylmorphine)
      │                 → Hydromorphone
      │
      ├── Codeine ───────→ Dihydrocodeine
      │
      └── Thebaine ──────→ Oxycodone
                        → Buprenorphine
                        → Naloxone / Naltrexone
                        → Etorphine

---

Mechanism of Action

• ↓ cAMP via Gi protein
• ↑ K⁺ efflux → hyperpolarization
• ↓ Ca²⁺ influx → reduced neurotransmitter release

---

Key Clinical Points

• Overdose triad: Pinpoint pupils + unconsciousness + respiratory depression
• Antidote: Naloxone (competitive μ-receptor antagonist)
• Tolerance & dependence: Develop rapidly with repeated use
• Withdrawal: Opposite of opioid effects — mydriasis, diarrhea, tachycardia, piloerection, anxiety

---

---

Clinical Scenario

---

Questions & Answers

① Calculate the dose of dopamine required

5 mcg/kg/min × 60 kg = 300 mcg/min

---

② Calculate the volume of drug required

Dose needed = 300 mcg/min

Volume/min = 300 mcg/min ÷ 40,000 mcg/mL = 0.0075 mL/min

---

③ Which IV fluid is to be used?

• Dopamine is compatible with both
• D5W is most commonly used in standard dopamine infusion preparation
• Avoid alkaline solutions (sodium bicarbonate) — dopamine is inactivated in alkaline pH

---

④ Calculate the rate of infusion

Total volume = 505 mL ≈ 500 mL Concentration = 200 mg / 500 mL = 0.4 mg/mL = 400 mcg/mL

Dose = 300 mcg/min

Rate = 300 mcg/min ÷ 400 mcg/mL = 0.75 mL/min = 45 mL/hour

0.75 mL/min × 20 drops/mL = 15 drops/min

---

Part 2 — Prescription Question (Alcoholic Patient with Amoebic Dysentery)

• ① Metronidazole tablet 100 mg
• ② Metronidazole tablet 200 mg — 3× a day
• ③ Furazolidone tablet 100 mg — 1 tablet daily orally

---

Critique & Correction

---

Corrected Prescription

1. Tab. Metronidazole 800 mg — TDS × 7 days
   (With food; avoid alcohol completely)

2. Tab. Diloxanide furoate 500 mg — TDS × 10 days
   (Luminal agent to eradicate cysts after metronidazole)

CAUTION: Patient is alcoholic — warn about 
disulfiram-like reaction with metronidazole.

Metronidazole kills trophozoites (tissue amoeba). Diloxanide furoate eliminates luminal cysts to prevent relapse — the two together constitute complete treatment of amoebic dysentery.

Experiment on Frog Isolated Heart

---

Aim

---

Principle

---

Requirements

• Frog (Rana tigrina)
• Frog Ringer's solution (NaCl 6.5g, KCl 0.14g, CaCl₂ 0.12g, NaHCO₃ 0.2g per litre, pH 7.2)
• Kymograph + heart lever (frontal writing lever)
• Cannula (Straub cannula)
• Drugs: Adrenaline, Acetylcholine, Atropine, Digitalis, KCl, CaCl₂, Adrenaline
• Dissection kit, thread, stand

---

Procedure

Preparation

1. Pith the frog (destroy brain and spinal cord)
2. Open the thorax, expose the heart
3. Identify: sinus venosus, atria, ventricle, aortic trunk
4. Tie a thread around the aorta, insert Straub cannula through the aorta into the ventricle
5. Perfuse with warm Ringer's solution to wash out blood
6. Attach thread from apex of ventricle to the heart lever on kymograph
7. Record normal baseline contractions (rate ~30–50 beats/min)

---

Normal Tracing Features

• Regular rhythm
• Equal amplitude
• Systole = upstroke | Diastole = downstroke
• Diastolic pause visible between beats

---

Drug Effects & Expected Results

1. Adrenaline (Epinephrine) — 1:10,000

---

2. Acetylcholine (ACh) — 1:10,000

---

3. Atropine → then ACh

Demonstrates competitive antagonism

---

4. Potassium Chloride (KCl) — excess

---

5. Calcium Chloride (CaCl₂) — excess

---

6. Digitalis (Digoxin)

---

Stannius Ligatures (Classical Experiment)

Proves: Sinus venosus (= SA node equivalent) is the primary pacemaker

---

Loewi's Experiment (Related Classic)

• Stimulated vagus of Heart 1 → slowed it
• Transferred perfusate to Heart 2 → Heart 2 also slowed
• Proved chemical neurotransmission (the substance = Acetylcholine)
• Nobel Prize 1936

---

Precautions

1. Ringer's solution must be at room temperature (~18–22°C)
2. Cannula must be free of air bubbles
3. Heart lever must be lightweight to avoid overloading
4. Wash heart with Ringer's between each drug application
5. Allow recovery to baseline before next drug
6. Drug concentrations must be accurate

---

Observations Table

---

Conclusion

• Myogenicity of the heart
• Autonomic pharmacology (sympathetic vs parasympathetic)
• Ionic basis of cardiac function
• Drug antagonism (atropine vs ACh)
• Pacemaker hierarchy (Stannius ligatures)

Essential Drugs (Essential Medicines)

---

Definition

"Those that satisfy the priority health care needs of the population. They are selected with due regard to disease prevalence, evidence on efficacy and safety, and comparative cost-effectiveness."

---

Criteria for Selection of Essential Drugs

---

Objectives / Importance of Essential Drugs

1. Rationalize drug use — reduce irrational prescribing
2. Reduce cost — cheaper generic versions prioritized
3. Ensure availability in all healthcare settings
4. Simplify procurement & storage
5. Improve quality control
6. Guide medical education and training
7. Facilitate drug donations during emergencies
8. Reduce counterfeit drug problems

---

WHO Essential Medicines List — Key Categories

1. Analgesics & Antipyretics

---

2. Antibiotics

---

3. Antimalarials

---

4. Antituberculosis Drugs

Standard regimen: 2HRZE / 4HR

---

5. Antiretrovirals (HIV)

---

6. Cardiovascular Drugs

---

7. Respiratory Drugs

---

8. GI Drugs

---

9. Antidiabetics

---

10. Vaccines (Immunologicals)

---

11. Oxytocics & Reproductive Health

---

12. Anaesthetics & Perioperative

---

13. Antiepileptics

---

14. Corticosteroids

---

15. Antidotes & Emergency Drugs

---

National Essential Medicines List (NEML)

---

Concept of Rational Drug Use (RDU)

Right drug — Right dose — Right route — Right duration — Right patient — Right cost

The "5 Rights" of Drug Prescription:

1. Right indication
2. Right drug
3. Right dose & route
4. Right duration
5. Right patient (no contraindications)

---

Key Points to Remember

---

Conclusion

• Equitable healthcare
• Reduced drug expenditure
• Minimized adverse drug reactions
• Improved therapeutic outcomes at population level