Pharmacology Flashcards

Question

Allergies (immunological) & timing | Immediate

Answer 1

•Type I – Immediate Hypersensitivity | –Anaphylaxis and urticaria with penicillins

Answer 2

``` Type II – cytotoxic antibody –Haemolysis with methyldopa –Thrombocytopenia with quinine •Type III – immune complex –Interstitial nephritis with penicillins •Type IV – Delayed Hypersensitivity –Stevens-Johnson sy. with carbamazepine –Pseudoallergic rash with amoxycillin ```

Answer 3

Infectious Mononucleosis •Increased likelihood of cutaneous reactions to penicillins and other antimicrobials •? mechanism - virus alters the immune status of the host. •drug can be readministered safely once the viral infection has resolved Human Immunodeficiency Virus •higher frequency of allergic reactions •Hypersensitivity to trimethoprim–sulfamethoxazole in 20 to 80%, (cf. 1-3%) •Mechanism -? altered drug metabolism or decreased glutathione levels Cystic Fibrosis •~ 30 % develop allergy to one or more antibiotics: •Piperacillin, ceftazidime, and ticarcillin •Mechanism: repeated exposure to antibiotics and immune hyper-responsiveness •Use lower doses + monitor carefully, or avoid

Answer 4

``` Women •Alcohol •Neuropsychiatric effects of mefloquine •ACE inhibitor cough •Drug-induced lupus •hepatitis: methyldopa, cholestasis: flucloxacillin Men •Cholestasis: co-amoxiclav •Use lower doses ```

Answer 5

``` •Elderly – diuretics, antihypertensives, beta-blockers –digoxin –NSAIDs –CNS-drugs – benzodiazepines –Tricyclic antidepressants –H1 antihistamines (chlorpheniramine) –H2-receptor antagonists (ranitidine) –Opiates ```

Answer 6

``` •CAFÉ: Clotting↓ Albumin↓ Fluid↑ Électrolytes ``` ``` •METRO: Metabolism↓ Encephalopathy Toxic (hepato-) drugs Renal ``` –toxicity: hepatocellular necrosis, cholestasis, steatosis –recovery affected > likelihood of developing * Screen for abnormalities (U+Es, INR, LFTs) * avoid/ reduce doses of specific drugs

Answer 7

``` These drugs are acetylated ‘HIPS’: •Hydralazine •Isoniazid •Procainamide •Sulphonamides ``` Slow acetylators (low N-acetyl transferase) ↑ incidence of drug-induced lupus

Answer 8

``` CYP2D6: 8% of UK lack this enzyme (AR) •metoprolol - bradycardia •flecainide - arrhythmias •amitriptyline - confusion •codeine - lack of effect (morphine) CYP2C9 •Warfarin – haemorrhage – as mean dose required is only 1.6 mg, not 5.5 mg •Tolbutamide - hypoglycaemia ```

Answer 9

‘favism’ (children who eat Broad bean Vicia Faba) •100 M people: •Africa, Med, Mid East, SE Asians * Acute haemolysis 2-3 d after oxidant substance * Self-limiting: only older cells (least enzyme) affected ``` Drugs causing haemolysis (oxidizing agents) •dapsone •methylene blue •nitrofurantoin •primaquine •quinolones •sulphonamides ```

Answer 10

* Itraconazole * Ketoconazole * Posaconazole (New) * Erythromycin * Clarithromycin * Telithromycin * HIV protease inhibitors * Nefazodone * Gemfibrozil * Cyclosporine * Danazol

Answer 11

unbound only

Answer 12

probenicid

Answer 13

amiodarone and CCBs (verapamil)

Answer 14

salycilates

Answer 15

``` weak acids (aspirin) are inhibited in alkaline urine (more ionized) ie sodium bicarb affects aspirin ```

Answer 16

diuretics, due to Na depeletion

Answer 17

•Pseudocholinesterase deficiency 1/2500 –↓↓metabolism of suxamethonium; rolonged paralysis ; screen relatives

Answer 18

1/20,000 GA (AD) –esp. gaseous halogenated agents, –release sarcoplasmic Ca – contraction, hypermetabolic –Dantrolene, cooling, O2, fluids, –Neuroleptic malignant sy. - clinically similar – haloperidol •Rx: dantrolene, dopamine agonists

Answer 19

Thiopurine Methyl Transferase (TPMT) defy (AR: 1 in 300) –azathioprine – severe toxicity ; screen to avoid

Answer 20

(AR: 1 in 300) –azathioprine – severe toxicity ; screen to avoid

Answer 21

alcohol amphetamines antidepressants antihistamines barbs + benzos (**diazepam is safe) cephalosporins diuretics Ergot Gold sex steroids (OCP) sulphonylamides sulphonylureas

Answer 22

``` I DRAFFT •ID of patient & drug •Dose •Route •Allergy-check •Formulation •Frequency •Timing ```

Answer 23

digoxin gentamycin cancomycin lithium also metformin

Answer 24

digoxin - high tissue binding lidocaine - lipid soluble heparin warfarin phenytoin - high plasma protein binding

Answer 25

amiodarone chlorpromazine