PPT important bits Flashcards
Methotrexate
Anti-metabolite
MOA = Inhibits dihydrofolate reductase (an enzyme needed for the synthesis of purines + pyramdines).
**Indications **= Inflammatory arthritis, Psoriasis, Chemo (e.g ALL)
Side effects = Mucositis, Myelosupression, Pneumonitis & Pulmonary fibrosis + Liver fibrosis.
Interactions!!!! - avoid prescribing trimethoprim or Co-trimoxaole concurrntly - this increases the risk of myelosupression!!! Aspirin also increases the risk of methotrexate toxicity (managed with folinic acid)
Beta blockers
MOA = bind to beta-adrenergic receptors, inhibiting the binding of Epinephrine & Norepinephrine. They reduce sympathetic activity.
Different beta blockers have different sensitivities for B1 (heart) and B2 (lungs) receptors.
They work to reduce BP by two main mechanisms;
* Reduce cardiac output - they are negatively ionotroping
* Reduce renin release.
Propanolol = can cross blood brain barrier
Atenolol + bisoprolol = cardioselective.
SE;
* Cold peripheries
* Vasospasm = contrainidctated in asthmatics.
* Fatigue
* sleep disturbance e.g nightmares
* Erectile dysfunction
Contraindications = asthma, sick sinus syndrome, concurrent verapamil use.
Loop diuretics
MOA = inhibit the Na/K/Cl pump in the loop of henle resulting in decreased absorption of NaCl
Indications = HF and HTN.
SE;
* Hypotension
* Hypokalemia
* Hyponatremia
* Hypochloremic alkaloisis
* Ototoxicity
* Hypocalcemia
* Renal impairment, gout, and hyperglycemia
Cytochrome P450 inducers
CRAP GPS
Carbamazepine
Rifampicin
Alcohol (chronic)
Phenytoin
Glucocorticoids
Phenobarbitone
Sulfonylureas / St johns wort
Cytochrome P450 inhibitors
SICKFACES.COM
Sodium valporate
Isoniazid
Cimetidine
Ketoconazole
Fluconazole
Alcohol (acute)
Chloramphenicol
Erythromycin / clarithromycin
Sulphonamides
Ciprofloxacin
Omeprazole
Metronidazole
Grapefruit juice
Ivabridine
MOA = Inhibits If Sodium channels in the SA node, reducing cardiac pacemaker activity thus reducing HR. Improves exercise capacity in angina patients.
Used in HF and angina.
Adverse effects;
* bradycardia / heart block (hence why HR must be >75)
* visual affects
* headache
Hydralazine
Used in HF with a nitrate when ACEi/ARBs cannot be tolerated (i.e in people of Afrocarribean descent).
Also an antihypertensive.
MOA = blocks calcium channels in vascular smooth muscle thus decreasing vascular resistance.
SE = Flushing + GI disturbance
Subcutril-valsartan
Inhibits breakdown of naturetic peptides thus encourages diuresis and therefore lowers BP and contractility.
Must stop ACEi /ARBs with a washout period prior to starting this due to the risk of angiodema.
Nicorandil
It is a K+ channel activator which leads to vasodilation via activation of cGMP
SE;
* Flushing
* Headache
* GI (including anal), Skin & eye ulceration
Contraindicated in Left ventricualr failure
Mechanism of action of Loperamide
U-Opioid receptor agonist - reduces gastric motility.
Ondansetron
H-5T3 antagonist antiemetic
SE = prolonged QT interval + constipation
