Question

Hydralazine 50 mg, bid, hs

Fluvastatin 80 mg, one tab od

Spironolactone tab 25 mg, 1/2 tab bid

Amitriptyline 25 mg, od

what is the monitoring measure for the common side effect of each drug, the toxicity range and antidote the recommended management of toxicity?

Answer 1

1)HYDRALAZINE

Common side effect:Hypotension,headache,palpitations

Monitoring measures:Blood pressure(BP) and pulse should be monitored frequently during initial dose adjustment and periodically during therapy,should be used with caution in severe hepatic and renal impairment with monitoring of blood counts,LFT and RFT

Toxicity range:There is not report indicating death due to acute toxicity

• Highest known dose survived:adults,10g orally
• Oral LD59 in rats:173 and 187mg/kg

Antidote:

• No specific antodote.
• Gastric contents should be evacuated.
• Hypotension and shock to be treatred with plasma expanders,use vasopressor only if no other choice is left,tachycardia responds to betablockers.

2)FLUVASTATIN

Common side effect:muscle pain,tenderness or weakness(rhabdomyolysis),hematologic side effects like thrombocytopenia,leuckopenia,elevation of serum transaminases.

Monitoring measures:Monitor patient closely for signs of myopathy and rhabdomyolysis,perform LFT at start of therapy,and at 12 weeks after start of therapy or increase in dosage,bloodcounts.

Toxicity range:Doses greater than 80 mg/day.

Antidote:no specific antidote,to be treated symptomatically with laboratory monitoring and supportive measures.(Adverse drug reactuons from overdose may include peripheral neuropathy,diarrhoea,increased K⁺,myopathy,liver and renal problems etc)

3)SPIRONOLCATONE

Common side effect:lightheadedness,hyperkalemia,agranulocytosis,elevated BUN.

Monitoring measures:Blood pressure,serum electyolytes(especially potassium,within 1 week of initiation or dose titration and regularly thereafter),BUN,blood count,volume status

Toxicity range:greater than maximum dose of 400 mg/day.

Antidote:no specific antidote,treatment is supportive and symptomatic.

• Acute ingestion-stomach emptying by emesis or lavage.
• Severe hyperkalemia-reduce serum potassium levels with IV sosium bicarbonate or glucose with insulin,or by using cation exchange resins such as sodium polystyrene sulfonate.

4)AMITRYPTYLLINE

Common side effect:Anticholinergic side eeffects like constipation and dry mouth,seizures,agranulocytosis,thrombocytopenia,leukopenia,ECG changes.

Monitoring measures:Check vitals regularly for decreased BP or tachycardia,blood counts,ECG,blood glucose etc.

Toxicity range:narrow therapeutic index drug,10-20 mg/kg is life threatening(risk of toxicity is incresed when serum levels are greater than 500ng/ml)

Antidote:The first 12 hours of ingestion after acute ingeation is characterised by excessive anticholinergic activity,physostigmine can be used as anb antidote in life-threatening situations.

• Parenteral diazepam or phenytoin-for seizures.
• Parenteral lidocaine-foir arrythmias.
• Sodium bicarbonate-for acidosis.