Pharmacology Flashcards by Lor L

What are the effects of Local anaesthetics?

Slow rate of depolarization.
Slow axonal conduction
Increase threshold potential.
Reduce height of action potential.
No effect on RMP

“SSIR No”

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What is the mechanism of action for local anaesthetics?

Physical blockade of voltage gated Na+

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What happens when local anaesthetics provides a physical blockade for Na+ channels?

Blockade Increase Na+ channel recovery time (10-1000 times)= prolonged refractory period Ultimately prevent propagation of AP

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What are examples of Esters?

Please - Procaine
Bring - Benzocaine
The- Tetracaine( Amethocaine)
Cocaine

” Please bring the cocaine”

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What are examples of Amides?

Roy - Ropivacaine
Brought - Bupivacaine
Pain - Prilocaine
Medication - Mepivacaine
Late- Lignocaine

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Which local aesthetic drugs are weak bases (pKa 8-9) (poor solubility in water) & given as HCl salts, water soluble?

Procaine
Lignocaine
Benzocaine

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Where is the receptor site for local anaesthetics located?

On the innerside of the membrane

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True or False? Local anaesthetics bind most avidly to the activated state of sodium channels.

FALSE!! They bind most avidly to the INACTIVATED state .

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True or False? The greater the firing frequency of an axon, the greater the blockade.

TRUE!!

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True or False? Local anaesthetics DOES NOT promote hyperpolarization.

TRUE!!

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Why do local anaesthetics have no effect on the resting membrane potential?

This is because the resting membrane potential; is controlled by the sodium potassium ATP-ase NOT Voltage- gated Sodium channels

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True or False? In regards to local anaesthetics, The larger the diameter of the nerve the greater the susceptibility.

FALSE!! The smaller the diameter of the nerve the greater the susceptibility

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Which fibers are most sensitive to block for local anaesthetics?

Type C fibres

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True or False? The closer the pka is to 7.4 , the faster the onset of the drug.

TRUE!!

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What are factors that will affect the use of local anaesthetics?

Acidic environment facilitates the population of the charged form
Basic environment is low in H ions and facilitates the free base

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True or False? Local Anaesthetics does NOT react faster if there is inflammation at the site.

TRUE!! Local anaesthetics does NOT react faster if there is a site of inflammation due to its acidic environment so the antilog is MORE and there will be less BASE form so the drug will work less and even have more adverse effects .

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Which local anaesthetic drug was the first to be discovered?

Cocaine was the first local anaesthetic drug to be discovered

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By what process do local anaesthetics enter the body through?

Passive diffusion

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Which local anaesthetic drug is applied ONLY Topically ?

Benzocaine

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By what enzyme are Local Anaesthetics (ESTERS) metabolised & eliminated?

By the enzyme plasma pseudocholinesterases to produce Para-aminobenzoic acid (PABA).

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True or False? Local anaesthetics ( AMIDES) are metabolised through the kidneys.

FALSE!! Hepatic metabolism so liver

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Which Local anaesthetic ( ESTERS) is NOT metabolised by the enzyme plasma pseudocholinesterases to produce Para-aminobenzoic acid (PABA)?

COCAINE- It goes through Hepatic metabolism

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Which local aesthetic drug is associated with causing Methemoglobinaemia due to production of toluidine on metabolism?

Prilocaine

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Allergic reactions are seen with which type of local anaesthetics?

Esters - due to PABA from metabolism.

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Fill in the blanks. " Most local anaesthetics are vasodilators EXCEPT ___________ which is a Vasoconstrictor."

Cocaine = Vasoconstrictor

What are the adverse effects of Cocaine?

CV= -vasoconstriction, increase BP, Arrhythmias CNS = Euphoria

True or False? Esters EXCEPT cocaine have a longer duration than Amides.

FALSE!! Esters ( EXCEPT Cocaine) has a SHORTER duration.

Which type of local aesthetic has a Greater potency and a less vasodilation potential?

Amides

Which drug is used only topically for anaesthesia of the respiratory tract as 1%, 4% or 10% solution?

Cocaine

Which Local Anaesthetic drug is used rectally for itching & pains associated with hemorrhoids Itching and pains associated with sunburns etc?

BENZOCAINE

Which Local anaesthetic drug is mainly used WITH a vasoconstrictor ?

Lignocaine

Which local anaesthetic can be used without a vasoconstrictor ?

Prilocaine

Which Opioid receptor mediates the most actions of Opioids?

Mu receptor

What are examples of Strong Opioid Agonists?

Morphine Meperidine (Pethidine) Oxymorphone Methadone Forgot - Fentanyl, Henry - Hydromorphone Loves - Levorphanol Heroin " MMOM Forgot Henry Loves Heroin"

What are examples of a Moderate or Weak Opioid Agonist?

Betty - Buprenorphine Hates - Hydrocodone C- Coedine O- Oxycodone P- Propoxyphene s

Which drug is one of the few Opioids drugs used to treat coughing?

Codeine

Which drug us a Synthetic analogue of Codeine?

Tramadol

What is the Mechanism of action for Tramadol?

* Weak Mu receptor agonist * Inhibition of reuptake of serotonin and NE

What are the adverse effects of Tramadol?

* Dizziness, constipation, NV, headache, somnolence * Pruritus, CNS stimulation ( nervousness, anxiety, agitation, mood swings, hallucinations) * Increase risk of seizures with SSRIs, TCAs

Which drug is a derivative of Levorphanol?

Dextromortophan - cough suppressant

Diphenoxylate is a derivative of what drug and what is its function ?

Pethidine- used to treat diarrhoea

Which drug is derivative of pethidine used to stimulate Mu receptors in myenteric plexus → anti-diarrhoeal action ,used to treat diarrhoea and does not cross BBB, hence no analgesic effect?

Loperamide

What are Mixed Agonist- Antagonists of Opioids?

Pentazocine Nalbuphine Butorphanol

What is used to treat Opioid overdose?

Naloxone & Naltrexone

What is the MOA of Morphine?

Binds primarily to Mu receptors. both reducing neurotransmitter release from presynaptic nocieptive neurons (via ↓Ca 2+ entry) and hyperpolarizing & thereby inhibiting postsynaptic neurons (via ↑K+ conductance)

What are the clinical uses of Morphine?

H- Histamine release E- Emesis C- Contraction of smooth muscle in biliary tract, bladder & ureter ( increase ADH release ----> urinary retention) k of a D- Decreased cough reflex D- Decreased GI motility D- Decreased uterine tone D - Depression of mental functioning. R- Respiratory depression E- Euphoria A- Analgesia M- Miosis

What are the withdrawal symptoms of Morphine?

Lacrimation Rhinorrhoea Sweating Gooseflesh Nausea Tachypnoea

A triad of coma, pinpoint pupils ,respiratory depression indicates an overdose of which drug?

Morphine

Which adjuvant medications may be administered with morphine to reduce adverse effects?

Anti-emetics Laxative

Which Opioid agonist is widely used in labour & post-op pain management?

Pethidine (Meperidine)

At what time duration does Morphine withdrawal symptoms peak?

36-72 hours

True or False? Fentanyl is more potent than Sufentanil.

FALSE!! Sufentanil 5x more potent than fentanyl.

Which Opioid agonist is used in the treatment of Opioid withdrawal symptoms particularly in cases of heroin dependence?

Methadone

Which Weak Opioid agonist is Obtained naturally or by methylation of morphine?

Codeine

Which enzyme is responsible for the demethylation of Codeine & what type of people are it absent in?

CYP2D6 enzyme - It is absent in 7% Caucasian pop. → these persons will derive little benefit from codeine .

What are the adverse effects of Codeine?

Constipation Somnolence ( feeling sleepy) , Nausea Vomiting Respiratory depression only at very high doses.

Which Opiod drug is a Agonist at Kappa receptors and partial agonist at Mu receptors?

Pentazocine

What are the adverse effects of Pentazocine?

Anxiety Unpleasant dreams Hallucinations Nausea Sweating

What is the MOA for Tramadolol?

* Weak Mu receptor agonist * Inhibition of reuptake of serotonin and NE

Which drug can have an increased risk of seizures with SSRI's and TCA's?

Tramadol

True or False? Naloxone has a longer duration of action than Naltrexone.

FALSE!! Naltrexone has a longer duration of action . Naloxone- 1-2 hrs Naltrexone- 48 hr

What are the adverse effects of Naltrexone?

* Hepatotoxicity * Nausea *Sedation * Headache

What are the adverse effects of Naloxone?

* Tachycardia * Arrhythmias

Which Local aesthetic ( Esters) is used only for Infiltration Anaesthesia?

Procaine

Which Local anaesthetic drugs can be infiltrated ( Direct injection into tissues to act on a local nerve ending Given with epinephrine except in tissue with end- arteries(fingers, toes, penis) ?

Lignocaine Procaine Bupivacaine

Which local anaesthetics can be applied Topically?

Tetracaine Lignocaine, Cocaine Benzocaine

Pharmacology Flashcards

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