NEET MDS Lessons
Pharmacology
Adverse effects
Nitrates
– Headache, hypotension, dizziness, lightheadedness, tachycardia, palpitations
Beta-adrenergic blocking agents
– hypotension, bradycardia, bronchospasm, congestive heart failure
Calcium channel blockers
– hypotension, dizziness, lightheadedness, weakness, peripheral edema, headache, congestive heart failure, pulmonary edema, nausea, and constipation
Drugs that increase effects of Antianginal drugs
• Antihypertensive
• Diuretics
• Phenothiazine antipsychotic agents
• Cimetidine
• Digoxin
Drugs that decrease effects of Antianginal
• Adrenergic drugs - epinephrine
• Anticholinergic
• Calcium salts
• Phenobarbital, Phenytoin
Adjunctive Antianginal Drugs
In addition to antianginal drugs, several other drugs may be used to control risk factors and prevent progression of myocardial ischemia to myocardial infarction and sudden cardiac death.
These may include:
• Aspirin. This drug has become the standard of care because of its antiplatelet (ie, antithrombotic) effects. Recommended doses vary from 81 mg daily to 325 mg daily or every other day; apparently all doses are beneficial in reducing the possibility of myocardial reinfarction, stroke, and death. Clopidogrel 75 mg/day,
Is an acceptable alternative for individuals with aspirin allergy.
• Antilipemics. These drugs may be needed by clients who are unable to lower serum cholesterol levels sufficiently with a low-fat diet. Lovastatin or a related “statin” is often used. The goal is usually to reduce the serum cholesterol level below 200 mg/dL and lowdensitylipoprotein cholesterol to below
130 mg/dL.
• Antihypertensives. These drugs may be needed for clients with hypertension. Because beta blockers and calcium channel blockers are used to manage hypertension as well as angina, one of these drugs may be effective for both disorders.
Mixed Narcotic Agonists/Antagonists
These drugs all produce analgesia, but have a lower potential for abuse and do not produce as much respiratory depression.
A. Pentazocine
- Has a combination of opiate analgesic and antagonist activity.
- Orally, it has about the same analgesic potency as codeine.
- In contrast to morphine, cardiac workload tends to increase due to an increase in pulmonary arterial and cerebrovascular pressure. Blood pressure and heart rate both also tend to increase.
- Adverse reactions to Pentazocine
• Nausea, vomiting, dizziness.
• Psychotomimetic effects, such as dysphoria, nightmares and visual hallucinations.
• Constipation is less marked than with morphine.
B. Nalbuphine
- Has both analgesic and antagonist properties.
- Resembles pentazocine pharmacologically.
- Analgesic potency approximately the same as morphine.
- Appears to be less hypotensive than morphine.
- Respiratory depression similar to morphine, but appears to peak-out at higher doses and to reach a ceiling.
- Like morphine, nalbuphine reduces myocardial oxygen demand. May be of value following acute myocardial infarction due to both its analgesic properties and reduced myocardial oxygen demand.
- Most frequent side effect is sedation.
C. Butorphanol
- Has both opiate agonist and antagonist properties.Resembles pentazocine , pharmacologically., 3.5 to 7 times more potent than morphine., Produces respiratory depression, but this effect peaks out with higher doses. The respiratory depression that does occur lasts longer than that seen following morphine administration.
- Butorphanol, like pentazocine, increases pulmonary arterial pressure and possibly the workload on the heart.
- Adverse reactions include sedation, nausea and sweating.
D. Buprenorphine
- A derivative of eto`rphine. Has both agonist and antagonist activity. 20 to 30 times more potent than morphine.Duration of action only slightly longer than morphine, but respiratory depression and miosis persist well after analgesia has disappeared.
- Respiratory depression reaches a ceiling at relatively low doses.
- Approximately 96% of the circulating drug is bound to plasma proteins.
- Side effects are similar to other opiates:
- sedation, nausea, vomiting,
- dizziness, sweating and headache.
Antidiarrheal
Antidiarrheal drugs may be given to relieve the symptom (non-specific therapy) or may be given to treat the underlying cause of the symptom (specific therapy).
Ι. Drugs used for the symptomatic (non-specific) treatment of diarrhoea include:
• Opiates and opiate derivatives are the most effective (such as morphine), but it is not used because of potentially serious adverse effects. Other agents, such as diphenoxylate and loperamide, are commonly used.
• Adsorbent – demulcent products such as kaolin – pectin preparation may be included in antidiarrheal preparations. Unfortunately, they may adsorb nutrients and other drugs, including the antidiarrheal agents if given concurrently.
• Anticholinergic agents e.g. atropine is occasionally used to decrease abdominal cramping and pain associated with diarrhoea.
ΙΙ. Specific therapy may include the use of antibacterial agents that are recommended for use in carefully selected cases of bacterial enteritis. For example, severe diarrhoea by salmonella, shigella, campylobacter and clostridia species can be treated by antibiotics (ampicillin, chloramphenicol, co-trimoxazole).
COAGULANTS
An agent that produces coagulation (Coagulation is a complex process by which blood forms clots).
ANTICOAGULANTS
An anticoagulant is a substance that prevents coagulation; that is, it stops blood from clotting.
Anticoagulants:
Calcium Chelators (sodium citrate, EDTA)
Heparin
Dalteparin Sodium (Fragmin) -Low molecular-weight heparin
Enoxaparin - Low molecular-weight heparin
Tinzaparin Sodium - Low molecular-weight heparin
Warfarin
Lepirudin - recombinant form of the natural anticoagulant hirudin: potent and specific Thrombin inhibitor
Bivalirudin - analog of hirudin: potent and specific Thrombin inhibitor
Procoagulants:
Desmopressin acetate
Antiplatelet Drugs:
Acetylsalicylic Acid, Ticlopidine, Sulfinpyrazone, Abciximab , Clopidogrel bisulfate
Fibrinolytic Drugs:
Tissue Plasminogen Activator (t-PA, Activase), Streptokinase (Streptase),
Anistreplase, Urokinase
Antagonists:
Protamine sulfate, Aminocaproic acid
Pharmacological agents used to treat blood coagulation disorders fall in to three major categories:
1. Anticoagulants: Substances that prevent the synthesis of a fibrin network which inhibits coagulation and the formation of arterial thrombi and thromboembolic clots.
2. Antiplatelet agents: Substances that reduce the adhesion and aggregation of platelets.
3. Fibrinolytic agents: Substances that promote the destruction of already formed blood clots or thrombi by disrupting the fibrin mesh.
Nalidixic acid:
Nalidixic acid is the basis for quinolone antibiotics. It acts bacteriostatically (that is, it inhibits growth and reproduction) or bactericidally (it kills them) on both Gram positive and Gram negative bacteria, depending on the concentration. It is especially used in treating urinary tract infections, caused for example by Escherichia coli, Proteus, Enterobacter and Klebsiella.
Ciprofloxacin : Ciprofloxacin is bactericidal and its mode of action depends on blocking of bacterial DNA replication by binding itself to an enzyme called DNA gyrase
Ciprofloxacin is a broad-spectrum antibiotic that is active against both Gram-positive and Gram-negative bacteria.
Enterobacteriaceae, Vibrio, Hemophilus influenzae, Neisseria gonorrhoeae
Neisseria menigitidis, Moraxella catarrhalis, Brucella, Campylobacter,
Mycobacterium intracellulare, Legionella sp., Pseudomonas aeruginosa,
Bacillus anthracis - that causes anthrax
Weak activity against: Streptococcus pneumoniae,
No activity against: Bacteroides, Enterococcus faecium, Ureaplasma urealyticum and others
It is contraindicated in children, pregnancy, and epilepsy.
Ciprofloxacin can cause photosensitivity reactions and can elevate plasma
theophylline levels to toxic values. It can also cause constipation and sensitivity to caffeine.
Dosage in respiratory infections is 500-1500 mg a day in 2 doses.
Dental implications of these drugs:
1. Adverse effects: gingival hyperplasia (phenytoin), osteomalacia (phenytoin, Phenobarbital), blood dyscrasias (all but rare)
2. Drug interactions: additive CNS depression (anesthetics, anxiolytics, opioid analgesics), induction of hepatic microsomal enzymes (phenytoin, Phenobarbital, carbamazepine), plasma protein binding (phenytoin and valproic acid)
3. Seizure susceptibility: stress can → seizures