Case Study 1 40-year-old woman * Desyrel 300 mg bid * Klonopin 2 mg bid * Aricept 10 mg qd * Zoloft 100 mg qd * Synthroid 0.25 mg qd * Detrol XL 4 mg qd * Norpace 150 mg bid * Inderal 80 mg bid * Bumex 2 mg qd * Aldactone 100 mg qd * Avapro 300 mg qd * Prinivil 40 mg qd * Glucophage 850 mg bid
DESYREL (1) 300 mg bid The active pharmaceutical ingredient in it is trazadone, an oral drug available as a regular/extended release tablet to be taken twice daily. STRUCTURE
MECHANISM OF ACTION It is a selective serotonin receptor inhibitor that inhibits reuptake of serotonin and causes subsensitivity of adrenoceptors. It induces significant changes in 5HT presynaptic adrenoceptor. It also blocks histamine (H1) and α1- adrenergic receptors significantly. SIDE EFFECTS:
Headache, nausea, vomiting, diarrhea, constipation, weakness, nervousness, confusion, muscle pain, rash, sweating, blurred vision, ringing in ears, shortness of breath, dry mouth, fainting. POTENTIAL DRUG INTERACTIONS (2)
Drugs that interactInteraction categoryParameters alteredSuggestion Disopyramide Contraindicated QTc interval prolongationThis combination is not to be used. Sertraline Serious interactions Increase in serotonin levelsAn alternative is to be used
Tolteridone and clonazepam Significant interactions Decrease cholinergic effects and increase sedationTo be monitored closely Metformin and bumetanideMinor interactionsIncrease in metformin effects by pharmacodynamic synergismTo be monitored
KLONOPIN (1) 2mg bid The active pharmaceutical ingredient in it is clonazepam, an oral drug to be taken twice daily. STRUCTURE
MECHANISM OF ACTION The exact mechanism is not clear, but it increases the activity of GABA receptors. In absence seizures it suppresses the spike and wave discharge by reducing nerve transmission in the motor cortex. SIDE EFFECTS
Drowsiness, dizziness, coordination problems, blurred vision, increased saliva production, frequent urination and swelling of eyes, lips, and throat. POTENTIAL DRUG INTERACTIONS (2) Drugs that interactInteraction categoryParameters alteredSuggestion TrazodoneSignificant interactionsIncreases sedationTo be monitored closely
ARICEPT (1) 10mg qd The active pharmaceutical ingredient in it is donepezil. It is available as oral dosage form taken once daily. STRUCTURE
MECHANISM OF ACTION It is a centrally acting acetylcholinestarase inhibitor, an enzyme responsible for the hydrolysis of acetylcholine. This results in the increased concentrations of acetylcholine available for the synaptic transmission in CNS. It is mainly used in the treatment of Alzheimer’s disease, which increases cortical acetylcholine. SIDE EFFECTS
Nausea, vomiting, loss of appetite, weight loss, muscle cramps, tiredness, depression, confusion, behavioral changes, hallucinations and red or itchy skin. POTENTIAL DRUG INTERACTIONS (2) Drugs that interactInteraction categoryParameters alteredSuggestion Tolteridone Significant interactions Decreases cholinergic effects To be monitored
Sertraline and trazodoneMinor interactionsEffects hepatic enzyme CYP2D6 metabolism and decreases cholinergic effects
To be monitored
ZOLOFT (1) 100mg qd The active pharmaceutical ingredient is sertraline, to be taken once daily. STRUCTURE
MECHANISM OF ACTION It is involved in the inhibition of CNS neuronal uptake of serotonin (5HT) SIDE EFFECTS Blurred vision, nausea, diarrhea, constipation, gas/bloating, drowsiness, dizziness, loss of appetite, sore throat, changes in sex drive, tingling in hands and feet.
POTENTIAL DRUG INTERACTIONS (2) Drugs that interactInteraction categoryParameters alteredSuggestion Trazodone Serious interactions Increase in serotonin levelsAn alternative is to be used
Propranolol
Significant interactions
Increased effects of propranolol by affecting hepatic enzyme CYP2D6 metabolism To be monitored closely
Donepezil, tolteridone and bumetanide Minor interactions Pharmacodynamic synergism To be monitored
SYNTHROID (1,3) 0.25 mg qd The active pharmaceutical ingredient in it is levothyroxine (T4), taken once daily. STRUCTURE
MECHANISM OF ACTION It is a synthetic form of thyroxine (T4), secreted by thyroid gland. T4 is converted to T3 (Triiodothyronine). T3 and T4 when bound to thyroid receptor proteins it stimulate metabolic effects by transcription and protein synthesis. SIDE EFFECTS
Tremors, weight loss, headache, stomach cramps, menstrual cycle changes, nervousness, temporary hair loss and arrhythmia. POTENTIAL DRUG INTERACTIONS (2) No potential drug interactions were found.
DETROL (1) 4mg qd The active pharmaceutical ingredient in it is tolterodine, taken once daily. STRUCTURE
MECHANISM OF ACTION It is a competitive antagonist of muscarinic receptors, which involves in the contraction of urinary bladder. It increases residual urine volume and decreases detrusor muscle pressure. SIDE EFFECTS
Dry mouth, blurred vision, stomach upset, constipation, rash, chest pain, difficulty urinating.
POTENTIAL DRUG INTERACTIONS (2) Drugs that interactInteraction categoryParameters alteredSuggestion Donepezil and trazodone
Significant interactions
Donepezil increases cholinergic effects and tolteridone decreases cholinergic effects.To be monitored
Sertraline Minor interactionsIncreases tolteridone effects by affecting CYP2D6 metabolismTo be monitored
NORPACE (1,3) 150mg bid The active pharmaceutical ingredient is disopyramide to be taken twice daily. STRUCTURE
MECHANISM OF ACTION It is a class 1a anti-arrhythmic drug, which decreases myocardial excitability. It also decreases disparity in refractory period between normal and infarcted myocardium. It has anticholinergic, peripheral vasoconstrictive, and negative inotropic effects. SIDE EFFECTS
Dizziness, dry mouth, stomach pain, headache, blurred vision, constipation, urination difficulty.
POTENTIAL DRUG INTERACTIONS (2) Drugs that interactInteraction categoryParameters alteredSuggestion Trazodone Contraindicated QTc interval prolongation This combination is not to be used
Spironolactone
Significant interactions
Increased effects of disopyramide by pharmacodynamic synergism. To be monitored closely
INDERAL (1) 80 mg bid The active pharmaceutical ingredient is propranolol, taken twice daily. STRUCTURE
MECHANISM OF ACTION It is a non-selective beta-adrenergic blocker. It competitively blocks response to β1, β2 adrenergic stimulation. SIDE EFFECTS Dizziness, sleep difficulties, tiredness, stomach upset, rash, diarrhea, constipation.
POTENTIAL DRUG INTERACTIONS (2) Drugs that interactInteraction categoryParameters alteredSuggestion Sertraline, irbesartan and spironolactone
Significant interactions
Increases propranolol effects by affecting CYP2D6 metabolism. Irbesartan increases serum potassium levels To be monitored closely
BUMEX (1,3) 2mg qd The active ingredient is bumetanide, taken once daily. STRUCTURE
MECHANISM OF ACTION It interferes with chloride binding co-transport system in ascending loop of henle and proximal convoluted tubule and thereby inhibits reabsorption of sodium and chloride ions.
SIDE EFFECTS Muscle cramps, weakness, dizziness, faintness, thirst, stomach upset and diarrhea.
POTENTIAL DRUG INTERACTIONS (2) Drugs that interactInteraction categoryParameters alteredSuggestion Lisinopril and propranololSignificant interactions
Pharmacodynamic synergism and propranolol increases serum potassium levelsTo be monitored closely
ALDACTONE (1,3) 100 mg qd The active ingredient is spironolactone, taken once daily. STRUCTURE
MECHANISM OF ACTION It is a potassium-sparing diuretic, specific pharmacologic antagonist of aldosterone that acts primarily through competitive binding of receptors at the aldosterone dependent sodium potassium exchange site in distal convoluted tubule. SIDE EFFECTS
Headache, irregular menstrual periods, dizziness, thirst, tiredness, increased growth of hair on body parts, painful breasts, vaginal bleeding during post menopause.
POTENTIAL DRUG INTERACTIONS (2) Drugs that interactInteraction categoryParameters alteredSuggestion Lisinopril Significant interactions Pharmacodynamic synergism To be monitored closely
DisopyramideSignificant interactions Increase in disopyramide effects by pharmacodynamic synergismTo be monitored closely