Pharmacy Drugs Flashcards Preview

Smart Revision > Pharmacy Drugs > Flashcards

Flashcards in Pharmacy Drugs Deck (87)
Loading flashcards...
1

Thrombolytics

Streptokinase

Route of Administration - IVIntravenous

Indications
Life-threatening venous thrombosis, pulmonary embolism, arterial thromboembolism, acute myocardial infarction

Contraindications
Recent haemorrhage, trauma, surgery, aortic dissection, coma, history of cerebrovascular disease

Mechanism of Action
Forms a complex with and activates Plasminogen -> Plasmin

Adverse Drug Reactions
Nausea, vomiting, bleeding/haemorrhage

Drug-Drug Interactions
Often used in conjunction with anti-platelet and anti-coagulant drugs.

Therapeutic Notes
Streptokinase is derived from haemolytic streptococci, and is therefore antigenic. Repeated administration of streptokinase could therefore result in anaphylaxis.
If already used once previously, use t-PAs instead

2

Meglitidines

Examples
o Repaglinide
o Nateglinide

Indications - Uncontrolled non insulin dependant diabetes

Mechanism of action
o K+/ATP channel antagonists on β-cells, resulting in depolarisation, calcium entry and fusion of insulin containing vesicles with membrane

Adverse Drug Reactions
o Relatively lower risk of hypoglycaemia than Sulphonylureas
o Not associated with weight gain – useful in treating obese patients

3

Monoamine Oxidase Type B inhibitors

Examples
Selegiline

Route of Administration
Oral

Indications
Used on their own in mild cases of parkinsonism
Used in conjunction with L-DOPA to reduce end-dose ADRs

Mechanism of Action
Selegiline selectively inhibits the MAOB enzyme in the brain that is normally responsible for the breakdown of dopamine. By inhibiting breakdown, the dose of L-DOPA

Adverse Drug Reactions
Nausea
Hypotension
Psychiatric symptoms

4

Sulphonylureas

Examples
Gliclazide

Indications - Diabetes mellitus, in patients with residual β-cell activity

Contraindications - Breastfeeding women, elderly, renal and hepatic insufficiency

Route of Administration - Oral

Mechanism of Action
o Sulphonylureas antagonise β-cell K+/ATP activity, resulting in depolarisation. Voltage gated Ca2+ channels open, Ca2+ entry causes insulin vesicle fusion with cell membrane

Adverse Drug Reactions
o Hypoglycaemia
o GI disturbance
o Weight gain

Drug-Drug Interactions
o Highly protein bound (90-99%)

5

Glucocorticoids

Examples
o Prednisolone (Oral)
o Beclometasone - Inhaled
o Hydrocortisone - IV
o Dipropionate - nasal
o Fluticasone - Inhaled

Indications
o Immunosuppression
o Anti-inflammatory therapy
o Replacement of endogenous corticosteroids

Contraindications - Systemic infection

Mechanism of Action
o Diffuse into cytoplasm and bind receptor. Complex moves to nucleus and binds Hormone Response Element (HRE). Inducers/Inhibits transcription.

Adverse Drug Reactions
o Cushingoid effects
o Suppression of HPA axis
o Osteoporosis
o Suppression of growth in children
o Mineralocorticoid effects if the glucocorticoid also has those actions

Therapeutic Notes - Long term therapy must be withdrawn slowly, due to HPA suppression

6

Digoxin

Route of Administration
Oral bioavailability 70-80%

Indications
Supraventricular Arrhythmias (Atrial fibrillation), Heart Failure

Contraindications
Heart block, hypokalaemia

Mechanism of Action
Inhibits Na/K-ATPase
Increased Inotrope – Used in heart failure, no mortality benefit
Decreased Sympathetic outflow
Increased Parasympathetic outflow
Sensitises baroreceptor reflex
Combined Effects
Decreased Automaticity of SAN and AVN

Adverse Drug Reactions
Narrow therapeutic index
Toxicity enhanced with hypokalaemia
Cardiac toxicity – bradycardia, AVN block, atrial tachycardia

Drug-Drug Interactions
o Pharmacokinetic
Increased Digoxin Levels – Popafenone, Quinidine, Amiodarone, Verapamil, Spironolactone, Cylosporine

Redcued Digoxin Levels – Erythromycin, Tetracycline (gut bacteria metabolise digoxin)

o Pharmacodynamic
β-blockers, Verapamil, Diltiazem
Loop and Thiazide Diuretics (Hypokalaemia)

Therapeutic Notes
o Large volume of distribution, loading dose required for
o Loading dose split into 2 doses to minimise toxicity risk.
o Plasma levels checked 6-8 hours after dose at steady rate
o 20-30% protein bound
o Digoxin clearance is proportional to GFR (Reduce dose in elderly and renal impairment)

7

Mycophenolate Mofetil

Indications - Transplant immunosuppression (agent of choice)

Mechanism of Action
o Inhibits the enzyme Inosine Monophosphate Dehydrogenase, which is required for Guanosine synthesis
o Impaired B-cell and T-cell proliferation

Adverse Drug Reactions
o Myelosuppression -> Leukopenia, neutropenia
o Increased risk of infection (especially viral)

Therapeutic Notes
o Highly selective. Spares other rapidly dividing cells, due to the presence of guanosine salvage pathways

8

Faecal Softeners

Examples
Glycerol Suppositories

Route of Administration
Arachis Oil – Enema
Glycerol – Suppository

Indications
Constipation
Faecal impaction
Haemorrhoids
Anal fissures

Contraindications
Children less than 3 years old

Mechanism of Action
Lubricate and soften stools

Therapeutic Notes
Safe, but not always effective
Relatively slow to take effect

9

Thiazolineinediones

Examples
o Rosiglitazone
o Pioglitazone

Indications - Uncontrolled non insulin dependant diabetes

Contraindications
o Compromised HRH function
o Especially heart failure – can cause oedema

Mechanism of Action
o PPAR-γ agonist. Agonistically bind to a nuclear hormone receptor site.
o Reduction in gluconeogenesis and an increased glucose uptake into muscles

Adverse Drug Reactions
o GI disturbance
o Weight gain

Drug-Drug Interactions - Very heavily protein bound (~99%)

10

K+ channel blockers

Examples
Sotalol

Route of Administration
Orally or intravenously

Indications
Ventricular and supraventricular arrhythmias

Contraindications
AV block

Mechanism of Action
Block K+ channels (Phase 3)

Adverse Drug Reactions
Can cause arrhythmias (Torsades de Pointes)

Drug-Drug Interactions
Amiodarone inhibits CYP3A4, CYP2C9 and P-glycoprotein
Dose reductions of Warfarin, Digoxin, Flecainide needed

11

M2 Ion Channel Blockers

Examples
o Amantadine
o Rimantadine

Route of Administration - Oral

Indications
o Prophylaxis and treatment of acute Influenza A in groups at risk.

Mechanism of Action
o Inhibits the un-coating of a virus, therefore preventing it from being able to infiltrate into the cell. This occurs by the action of:
o Inhibits H+ influx into the cell, therefore preventing the change in pH which stimulates the viral un-coating.
o Blocks M2 Ion Channel, preventing breakdown of viral coat and release of viral RNA into host cell.

Adverse Drug Reactions
o Amantadine has more marked ADR risk than Rimantadine of ~5-10%, therefore Rimantadine is usually preferred
o Dizziness
o Hypotension
o GI disturbance
o Confusion, insomnia and hallucination can be problematic in the elderly (CNS)
o Is nephrotoxic in high doses

Therapeutic Notes
o Limited to Influenza group A, ineffective against group B
o Rapid emergence of M2 mutations in H5N1 viruses
o Resistance can develop quickly as only a single point mutation is needed in order to change the shape. This causes the binding site to move away from the channel, so that when the drug binds it will no longer block the channel E.g. amantadine in chicken feed leading to resistance

12

Heparin

Route of Administration Unfractionated – Intravenous
LMW – Subcutaneous

Indications
o Prophylaxis
Peri-operative (replace Warfarin)
Immobilised patients
o Treatment
DVT, PE, AF, MI, Unstable Angina

Contraindications
Haemophilia, Thrombocytopenia, Peptic Ulcers

Mechanism of Action
Activates Anti-Thrombin III
Unfractionated – Inhibits Thrombin (Factor IIa) and Factor XaLMW – Inhibits Factor Xa

Adverse Drug Reactions
Bleeding/Bruising/Haemorrhage
Heparin Induced Thrombocytopenia

Therapeutic Notes
Immediate onset, so can be used in an emergency / Warfarin cover
Monitor Unfractionated with aPTT, LMWH no need to monitor
Reverse effects with Protamine Sulphate

13

Lamotrigine

Route of Administration
Oral

Indications
All forms of epilepsy

Contraindications
Hepatic impairment
Not first line use in paediatric patients due to ADRs

Mechanism of Action
Prolongs VGSC inactivation state

Adverse Drug Reactions
Less marked CNS dizziness, ataxia, somnolence (drowsiness)
Nausea
Some mild (10%) and serious (0.5%) skin rashes, which limits child use

Drug-Drug Interactions
Adjunct therapy with other anti-epileptic drugs
Oral Contraceptives reduce Lamotrigine plasma levels
Valproate increases Lamotrigine plasma levels (protein binding)

Therapeutic Notes
Increasingly first line anti-epileptic drug
Appears to be safer in Pregnancy

14

Calcineurin Inhibitors

Examples
Cyclosporin (Binds Cyclophilin)
Tacrolimus (Binds Tacrolimus-Binding-Protein)

Indications
o Prevention of graft and transplant rejection
o Prevention of graft vs. host disease
o Atopic dermatitis, psoriasis

Route of Administration - Oral, intravenous

Mechanism of Action
o Reduction in IL-2 synthesis and release, via Calcineurin inhibition suppressing both cell-mediated and antibody-specific adaptive immune responses. Active against T helper cells.
o Ciclosporin binds to Cyclophilin and Tacrolimus binds to Tacrolimus-Binding-Protein
o Drug/Protein complexes bind to and inhibit Calcineurin, which normally has a phosphatase activity on the Txn factor for IL-2. Therefore, inhibition of Calcineurin reduces IL-2

Adverse Drug Reactions
o Nephrotoxic (proximal tubule), renal damage almost always occurs
o Hypertension in 50% of people
o GI disturbances

Drug-Drug Interactions
o Metabolism is by CYP450, so is affected by inducers/inhibitors

Therapeutic Notes
Unlike most immunosuppression agents, Cyclosporin does not cause myelosuppression

15

Rituximab

Indications - RA

Rituximab tends to stick to one side of B cells, where CD20 is. Increasing the effectiveness of natural killer (NK) cells in destroying these B cells

16

Amantadine

Route of Administration
Oral

Indications
Synergistic effect when used in conjunction with L-DOPA

Mechanism of Action
Stimulates neuronal dopamine release and inhibition of its reuptake
Additional muscarinic blocking actions

Adverse Drug Reactions
Anorexia
Nausea
Hallucinations

Therapeutic Notes
Modest anti-parkinsonian effects, but it is only of short-term benefit, since most of its effectiveness is lost within 6 months

17

Neuramidase Inhibitors

Examples
o Zanamivir
o Oseltamivir

Route of Administration
o Zanamivir – Inhaled
o Oseltamivir – Oral (80% bioavailability)

Indications
o Treatment of Influenza A or B virus within 48 hours after onset of symptoms when influenza is endemic in the community

Contraindications - Breast feeding

Mechanism of Action
o Inhibits neuraminidase enzyme which cleaves the virus from receptors on the membrane, once the virus has been produced. It causes aggregation of the virus at the cell surface, therefore preventing the virus from spreading throughout the body and therefore to other people also.
o Sialic acid analogues, with very high binding affinities for Neuramidase.
o The receptor is not involved with antigenic shift or drift

Adverse Drug Reactions
o Headache
o Nose bleed
o Respiratory depression (rarely)
o Bronchospasm
o GI disturbances

Therapeutic Notes
o Zanamivir has low bioavailability therefore is given as a dry powder inhalant. It is not used for prophylaxis.
o Oseltamivir is a pro-drug and by contrast is well absorbed, with 80% bioavailability. This enables it to be given orally for both treatment and prophylaxis.
o Gives rise to:
• 35-38% reduction in severity
• 25-36% reduction in duration when given as soon after infection as possible

18

Azathioprine

Indications
o Rheumatoid Arthritis, Inflammatory Bowel Disease
o Prevention of graft and transplant rejection
o Autoimmune conditions where corticosteroid therapy o alone inadequate
o Leukaemia

Route of Administration - Oral / IV

Mechanism of Action
o Azathioprine is a pro-drug, which is converted into 6-Mercaptopurine in the liver
o 6-Mercaptopurine is a fraudulent purine nucleotide that impairs DNA synthesis and has a cytotoxic action on dividing cells

Adverse Drug Reactions
o Myelosuppression -> Leukopenia, thrombocytopenia, anaemia
o Increased infection susceptibility
o GI disturbances (nausea, vomiting, diarrhoea)
o Drug-Drug Interactions
o Interacts with Allopurinol (treats gout), necessitates lowering of dose

Therapeutic Notes
6-Mercaptopurine is eliminated by the enzyme TPMT, which is subject to a high rate of genetic polymorphism. High levels of TPMT expression will lead to under-treatment, low levels of TPMT expression gives toxicity.

19

Cholesterol Absorption Inhibitors

Examples - Ezetimibe

Route of Administration - Oral

Indications
o Hyperlipidaemia resistant to dietary control, in statin intolerant patients
o Given in combination with a statin

Contraindications - Breastfeeding

Mechanism of Action
o Blocks NPC1L1 in the intestinal brush border, inhibiting cholesterol absorption, increasing LDL receptor upregulation leading to further reducitons
o Reduce LDL levels by 15-20%
o Ezetimibe also undergoes enterohepatic circulation, increasing its half-life.

Adverse Drug Reactions
o Gastrointestinal disturbances (Diarrhoea, pain)
o Headache

It is normally given as monotherapy in statin intolerant patients, however it will reduce LDL by a further 20% when given in combination with a statin. This is a better reduction than is gained by doubling statin dose and also reduces the risk of statin ADRs.

20

Ca2+ Channel blockers

Examples
Verapamil
Diltiazem
Amlodipine

Route of Administration
Oral

Indications
Supraventricular arrhythmias
Prophylaxis and treatment of angina and hypertension

Contraindications
Heart failure, bradycardia
AV Node Block

Mechanism of Action
Blocks Ca2+ channels responsible for depolarisation of pacemaker cells.

Adverse Drug Reactions
Hypotension, bradycardia, heart failure, heart block

21

Serotonin (5-HT3) Antagonists

Examples
Ondansetron

Route of Administration
Oral, IV or IM

Indications
In high doses in radiation sickness, chemotherapy sickness, post operatively

Mechanism of Action
5-HT is released into the gut, reducing Vagus activity, therefore effective at deactivating the vomiting centre (the Postrema on the floor of the 4th ventricle)
Blocks Serotonin receptors in Chemoreceptor Trigger Zone

Adverse Drug Reactions
Headaches, constipation, flushing

Drug-Drug Interactions
Anti-Emetic effect can be enhanced by a single dose of a corticosteroid

22

methylxanthines

Examples
o Theophylline
o Aminophylline

Indications
o Status asthmaticus
o COPD

Mechanism of Action
o Antagonise Adenosine receptors

Adverse Drug Reactions
o Psychomotor agitation
o Tachycardia

Therapeutic notes
o ADR profile means methylxanthines are 3rd or 4th line use for Asthma
o Narrow therapeutic window

23

Benzodiazepines

Examples
Diazepam
Lorazepam

Route of Administration
Oral, intravenous

Indications
Diazepam / Lorazepam – Status Epilepticus
Clonazepam – Absence seizures, short term use
Anxiety

Contraindications
Respiratory depression

Mechanism of Action
Act at a distinct receptor site on GABA Chloride channel
Binding of GABA or Benzodiazepines enhance each others binding, acting as positive allosteric effectors
Increases Chloride current into the neurone, increasing threshold for action potential generation

Adverse Drug Reactions
Sedation
Tolerance with chronic use
Dependence/Withdrawal with chronic use
Confusion, impaired co-ordination
Aggression
Abrupt withdrawal – seizure trigger
Respiratory and CNS depression

Drug-Drug Interactions
Highly protein bound (85-100%)
Some adjunct use

Therapeutic Notes
Well absorbed (90-100%), highly plasma bound (85-100%)
Linear Pharmacokinetics, t½s vary between 15-45hours
Side effects limit first line use
Overdose reversed by IV Flumazenil
Use may precipitate seizure/arrhythmia

24

Loop Diuretics

Examples
o Furosemide – 50% uptake
o Bumetanide – 90% uptake. More effective if there is presence of gut oedema, as the drug crosses the gut wall better. Can change to IV from oral to avoid this.


Route of Administration
o Oral, intravenous or intramuscular. Intravenous route used in emergencies as therapeutic effect is much faster (30 mins compared to 4-6 hours orally).

Indications
o Acute pulmonary oedema
o Oliguria (acute renal failure)
o Resistant heart failure
o Hypertension

Contraindications - Severe renal impairment

Mechanism of Action
o Inhibit the Na/K/Cl co-transporter in the luminal membrane
o Blocks reabsorption of Na+ and therefore water. Can block up to 5% of Na reabsorption

Site of Action - TAL of the loop of Henle

Adverse Drug Reactions
o Hypokalaemia, Hyponatraemia, hyperuricaemia, hypotension, hypovolaemia, metabolic alkalosis
o Bumetanide can cause Myalgia (occasionally, not very common)
o Furosemide can cause Ototoxicity

Drug-Drug Interactions
o Cardiac Glycosides – Hypokalaemia caused by loop diuretics potentiates the action of cardiac glycosides, increasing the risk of arrhythmias
o Aminoglycoside Antibiotics – (E.g. Gentamycin) Will interact with loop diuretics and increase risk of ototoxicity and potential hearing loss
o Steroids – Increased risk of hypokalaemia

25

Thiazide Diuretics

Examples
Bendroflumethiazide
Indapamide

Indications
Hypertension
Oedema secondary to congestive cardiac failure, liver disease or nephrotic syndrome

Contraindications
Hypokalaemia, Hyponatraemia, Hypercalcaemia

Mechanism of Action
Thiazide diuretics inhibit the Na+/Cl- co-transporter in the luminal membrane in the distal tubule of the kidney. This blocks the reabsorption of Na+ and therefore water. Result is lower blood volume and pressure.

Adverse Drug Reactions
Hypokalaemia, hyperuricaemia,
Impaired glucose tolerance
Hyponatraemia, hypermagnesemia, Hypercalcaemia,
Metabolic alkalosis
Cholesterol and triglyceride levels increase

26

Anti-TNF Agents

Examples
o Infliximab (Monoclonal Antibody)
o Adalimumab

Mechanism of Action
o Blocks the effects of TNF-α
o Decreased inflammation, decreased Angiogenesis, decreased joint destruction

Adverse Drug Reactions
o Increased infections
o Tiredness, dizziness
o Itching
o GI disturbances

27

Emergency Contraceptive

Levonorgestrel

Emergency Contraception
‘Morning after pill’ – Up to 72hrs after sex
Very high oral doses of progesterone (1.5mg) alone, or a Progestogen with an oestrogen to prevent implantation of fertilised egg
o 75% effective
o Indications – Emergency Contraception after unprotected sex
o Contraindications – Oestrogen contraindications, need to ask about cycle and when they had sex to determine if the woman is already pregnant. If this is the case it would be illegal to prescribe (abortion).

28

Atypical Antipsychotics

Examples
Olanzapine
Risperidone
Quetiapine
Clozapine

Route of Administration
Oral

Mechanism of Action
Higher affinity for 5-HT2A receptors than Dopamine D2 Receptors
Sedation – Within hours
Tranquilisation – Within hours
Antipsychotic – Several days or weeks

Adverse Drug Reactions
Vary between drugs
Olanzapine – Significant weight gain, suppressed “full” signals
Risperidone – Increased prolactin
Sedation
Extrapyramidal side effects at high doses

Toxicity
CNS depression
Cardiac toxicity
Risk of sudden death with high dose
Prolonged QT interval -> Torsades de points
Risk of sudden death with large dose

Therapeutic Notes
Atypical antipsychotics have less extrapyramidal side effects, so are therefore more acceptable to patients
First line treatment in schizophrenia

29

Aspirin

Route of Administration - Oral

Indications
o Prevention and treatment of MI / Ischaemic stroke, Analgesic
o Anti-inflammatory agent

Contraindications - Children under 12 years who are at risk of Reye’s Syndrome, Breastfeeding, Haemophilia, peptic ulcers, known hypersensitivity

Mechanism of Action - COX-1 Enzyme inhibitor, Prevents the formation of Thromboxane A2 from Arachidonic Acid in platelets. Thromboxane A2 stimulates phospholipase C, increasing calcium levels and causing platelet aggregation

Adverse Drug Reactions - Bronchospasm, GI haemorrhage

Drug-Drug Interactions - Displaces Warfarin from plasma proteins (PKs)
Increases Anti-Coagulant effect of Warfarin at a different site (PDs)

Therapeutic Notes
Aspirin at 150mg daily after MI has been shown to decrease mortality

30

Biguanides

Examples - Metformin

Indications- Type II diabetes – Endogenous insulin presence required

Contraindications
o Compromised HRH function
o In respiratory disease

Mechanism of Action
o Unknown
o Increases insulin receptor sensitivity, enhancing skeletal and adipose glucose uptake
o Inhibits hepatic gluconeogenesis
o Reduces hyperglycemia, but does not induce hypoglycemia
o Tends to be give 2-3 times a day prior to meals to provide acute negative feedback on top of a basal endogenous insulin signal


Adverse Drug Reactions
o GI disturbances – ameliorated by slow dose titration
o Lactic Acidosis