Top 100 Drugs III Flashcards by Gayathrie Velu

In what state and where is iron best absorbed?

Fe2+ (ferrous state)

Duodenum and jejunum

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Give 2 drugs that iron reduces absorption of?

Bisphosphonates

Levothyroxine

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What are examples of bulk-forming laxatives?

Ispaghula husk
Methylcellulose
Sterculia

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What are the major side effects of bulk-forming laxatives?

Mild abdominal distension
Flatulence
Faecal impaction
Bowel obstruction

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What are examples of osmotic laxatives?

Lactulose
Macrogol
Phosphate enema

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What are the indications for lactulose?

Constipation and faecal impaction
Bowel preparation prior to surgery/endoscopy
Hepatic encephalopathy

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What conditions must phosphate enemas be used with caution?

Heart failure
Ascites
Electrolyte disturbances

(causes significant fluid shifts)

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What are examples of stimulant laxatives?

Senna
Bisacodyl
Glycerol suppositories
Docusate sodium

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When are stimulant laxatives contraindicated?

Bowel obstruction

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What is the mechanism of action of lidocaine?

Blocks voltage-gated sodium channels

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What are the indications for lidocaine?

Local anaesthetic
Antiarrhythmic drug in VT
VF refractory to electrical cardioversion (although amiodarone more commonly used)

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What are indications for macrolides?

Respiratory and skin/soft tissue infection treatment where penicillin C/I due to allergy
Severe and atypical pneumonia
Triple therapy for H.pylori eradication

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What is the mechanism of action of macrolides?

Blocks 50S ribosome
Prevents translocation
Inhibits protein synthesis
BACTERIOSTATIC

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What are the major side effects of macrolides?

Irritant effects
Abx- associated colitis
Cholestatic jaundice
QT prolongation 
Ototoxicity (high doses)

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What drugs must macrolides be used in caution with?

Drugs that require P450 metabolisation since macrolides (erythromycin and clarithromycin inhibit P450).
E.g. warfarin, statins.
Drugs that prolong QT interval e.g. antipsychotics, SSRIs, amiodarone, quinine, quinolones

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What are the important adverse effects of metformin?

GI upset

Lactic acidosis

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When is metformin contraindicated?

Severe renal impairment

Withhold acutely in AKI, severe tissue hypoxia, acute alcohol intoxication, hepatic impairment

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How long prior to IV contrast injection must metformin be withheld for?

48 hours

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What are the indications for methotrexate?

DMARD
As part of chemotherapy for leukemia, lymphoma and solid tumours
Severe psoriasis

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What is the mechanism of action of methotrexate?

Inhibits dihydrofolate reductase (prevents conversion of folic acid to tetrahydrofolate)

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What are important adverse effects of methotrexate?

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Mucosal damage
Myelosuppression
Hypersensitivity reactions
Hepatitis, pneumonitis
Cirrhosis and pulmonary fibrosis (long-term)

Give 2 other examples of folate antagonists asides from methotrexate?

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Don’t prescribe in combo with methotrexate!

Trimethoprim
Phenytoin

What is the methotrexate dosing regimen for autoimmune disease treatment?

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7.5-20mg ONCE WEEKLY!

+ folic acid supplementation

What are the indications for metronidazole?

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Abx- associated colitis
Oral infections
Aspiration pneumonia
Surgical and gynaecological infections caused by anaerobes
Protozoal infections e.g. dysentery

What are the long-term neurological side effects associated with metronidazole use?

Optic neuropathy Seizures Encephalopathy

Why does metronidazole + alcohol cause a disulfiram-like reaction?

Metronidazole inhibits acetaldehyde dehydrogenase, which is needed to clear acetaldehyde (intermediate metabolite) from the body

What are the features of a disulfiram-like reaction?

Flushing Headache N&V

What drugs may reduce efficacy of metronidazole?

P450 inducers | e.g. phenytoin, rifampicin

When is naloxone indicated?

Treatment of opioid toxicity (associated with respiratory or neurological depression)

What is the mechanism of action of naloxone?

Competitive antagonist of opioid-u receptors, only works in the presence of exogenous opioids

What adverse effects may naloxone cause?

Opioid withdrawal reaction in opioid dependent patients: | Pain, restlessness, nausea, vomiting, dilated pupils, cold and dry skin with piloerection

When is nicorandil indicated?

Prevention and treatment of chest pain in stable angina

What is the mechanism of action of nicorandil?

Arterial and venous vasodilatation Through its actions as a nitrate and activating K+ATPase channels Efflux of K+ leads to hyperpolarisation, reduced intracellular Ca2+ and reduced smooth muscle contraction

In what conditions is nicorandil contraindicated?

LVF Hypotension Pulmonary oedema

What is the mechanism of action of varenicline?

Partial nicotinic receptor agonist Reduces withdrawal symptoms and the rewarding effects of smoking

What is the mechanism of action of buproprion?

Inhibits reuptake of noradrenaline or dopamine in the synaptic cleft

Give an example of a short acting and long acting nitrate?

Short acting - GTN | Long acting - ISMN

What are common SEs of nitrates?

``` Flushing Headaches Light-headedness Hypotension Tolerance with ISMN ```

What are the major contraindications for nitrate use?

Severe aortic stenosis | Haemodynamic instability

What is the mechanism of action of NSAIDs?

COX inhibitor | Reduces prostaglandin synthesis

Main adverse effects of NSAIDs?

``` GI toxicity + ulceration Renal impairment CV events Hypersensitivity reactions Fluid retention ```

What gastroprotection prescribed with an NSAID?

Lansoprazole 15mg daily

What are the important adverse effects of OCP/HRT?

``` Irregular bleeding Mood changes VTE Cardiovascular disease Increased risk of breast and cervical cancer ```

Concurrent use of P450 ______ reduces efficacy of contraception?

Inducers | e.g. rifampicin

What are the indications for co-codamol?

Mild to moderate pain

What is co-codamol and co-drydamol composed of?

Paracetamol + codeine/dihydrocodeine

What are the side effects of co-codamol and co-drydamol?

In normal doses- Nausea, constipation, drowsiness | In overdose- hepatotoxicity, respiratory and neurological depression

What are the indications for strong opioids?

1. Rapid relief of acute severe pain 2. Relief of chronic pain when other drugs on the ladder are insufficient 3. Relief of dyspnoea in palliative care 4. Relief of dyspnoea and anxiety in acute pulmonary oedema

What is the mechanism of action of opioids?

Blocks mu receptors in CNS Reduces neuronal excitability and pain transmission Blunts response to hypoxia and hypercapnia in medulla (reduces respiratory drive and breathlessness) Reduces sympathetic nervous system activity

What are the major adverse effects of opioids?

``` Respiratory depression Neurological depression N&V Pupillary constriction Constipation Itching Tolerance and dependence Withdrawal reaction ```

In what conditions should opioid doses be reduced?

Renal impairment Hepatic failure Elderly

Top 100 Drugs III Flashcards

(51 cards)