Pharmacology Flashcards
Carbimazole side effects
Agranulocytosis, neutropenia, cholesteric jaundice, alopecia
Pregnancy effects of warfarin
Central nervous system damage trimester 2&3
Is methyldopa safe in pregnancy
Safe in all trimesters
Effects of thiazide diuretics on pregnancy
Reduced placental perfusion
Trimephoprim method of action
Folate antagonist
UTI self help options
Water
Cranberry pills
Methenamine salts
Mannose receptors
Long term side effects of nitrofurantoin
Pulmonary fibrosis
Hepatitis
Is cefalexin safe in pregnancy
Yes
Mechanism of action of cirpofloxacin
(fluroquinolone) Interferes with DNA synthesis by disrupting the function of DNA gyrase.
What is misoprostol
synthetic prostaglandin E1 analogue
Example dosing of misoprostol
800mcg PV STOP for cervical priming
800mcg PV 24-48 hours after mifepristone for MTOP
how does misoprostol work
increases smooth muscle contraction
relaxes cervix
effect of prostaglandins on increasing gestation
increasing effect with increasing gestation
success of misoprostol when used combined with mifepristone in EMTOP
> 95%
which route is most effective for misoprostol
PV
where is misoprostol metabilised
liver
side effects of misoprostol
headache, fever, nausea, D&V, constipation, bleeding + excessive bleeding.
teratogenic effects of misoprostol?
moeibios syndrome, amniotic band syndrome, CNS deformity
contraindications to misoprostol
high risk of uterine rupture
placenta preavia
effects of misoprostol on pain?
increases pai sensitivity due to blockage of K+ channels
what is pharmacokinetics
what the body does to the drug
(absorbtion, distribution, elimination)
how do water soluble drugs cross cell membranes
active transport
how do lipid solouble drugs cross cell membranes
diffuse easily, usually from stomach or duodenum
what is bioavailabilty
the amount of drug that reaches circulation unchanged
what happens in phase 1 hepatic metabolism
drugs are reduced/oxilated/hydrolised into water solouble comounds
what sort of compounds do phase 1 metabolised drugs become
active, inactive, toxic
what is the phase 1 pathway in hepatic metabolism
cytochrome P450
what happens in phase 2 hepatic metabolism
drugs are conjugated usually to:
glucorunate (basic drugs)
acetate (acids)
sulphate (oral contraceptives)
what is enterhepatic circulation
feacaly-excreted drug can be reaborbed from the GI tract prior to excretion (eg COC)
how are soluble drusg excreted
renally (from blood flow from the liver)
bile (if molecular weight >300Da)
which part of the kidneys does the excretion
Proximal convoluted tubule
loop of Henle
what drugs are not renally excreted?
very large molecular drugs as cannot filter through kidneys (eg heparin)
what happens to insulin levels in pregnancy
pregnancy creates increasing insulin resistance, so insulin needs to go up
what is pharmacodynamics
what the drug does to the body (the drug effect)
What does phenytoin do
potent cytochrome P450 inducer (will reduce drug levels)
How does aciclovir work
inhibits HSV specific thymidine kinase
how does warfarin work
vitamin K epoxade reductase inhibitor
how does methotrexate work
dihydrofolate reductase inhibitor
how does gentamicin work
inhibition of ribosome synthesis
how does erythromycin work
inhibition of protein translocation
how does doxyxycline work
inhibition of protein translation
how might ampicillin effect COC
alters gut bacteria leading to reduced enetro-hepatic uptake
what is background incidence of congenital abnormality
2-3%
does heparin cross the placenta
no
how long is methotrexate present for
3 months
how long can retinoids affect a pregnancy for
up to 2 years
What are the main teratogen classes?
All the A’s
Anti-convulsants
Antibiotics
anti-coagulants
antimetabolites
antipsychotics
androgens
Acne drugs (A-vitamins)
alcohol
what drugs may cause miscarriage
ergotamine
misoprostol
mifepristone
thrombolytics
% patients with epilepsy who do not have a normal pregnancy
10%
risk of teratogenicty with sodium valproate
6%
valproate teratogenicty risks
dose related effect on verbal IQ
neural tube defects
safest anti-epiliptic drug in pregnacy
lamotrageine (3% approx baseline)
phenytoin teratogenic effects
cleft lip
microcephaly
cardiac abnormalities
mental retardation
carbemazipine teratogenic effects
cleft lip
microcephaly
cardiac abnormalities
mental retardation
neural tube defects
teratogenic risk reduction in epilepsy?
5mg folic acid 3 months
lowest effective dose
avoid polypharmacy
teratogenic abx classes
tetracyclines
sulphonamides
aminoglycosides
quinolones
nitrofuatoin
chloramphenicol
abx safe in pregnancy
penicillins
cephalosporins
macrolides
when is warfarin most teratogenic
weeks 6-12
in what situation would you keep someone on warfarin
metallic heart valve
Can misoprostol be used in breast feeding
No
Tamoxifene indications
BC treatment
BC prevention
Primary anovulatory infertility
MoA clomiphene
Blocks negative estrogen feedback at hypothalamus, causing FSH surge
Raloxifene indication
Prevention of osteoperotic vertebral factors
CV effects of tamoxifene
Decreased cholesterol decreased LDL
Major side effects SERMs
Increased VTE risk
Endometrial hyperplasia and polyps (tamoxifen)
Fluid retention, headaches, nausea, rash, fatigue, hot flushes, menstrual irregs
Cataracts (T)
Visual changes (C)
SERM C/I
Pregnancy, VTE (unless BC tx), ovarian cyst (C) liver diseaee
MoA heparin
Acts on Antithrombin III, causing inhibition of clotting factors IX, X (Xa+++), XI, XIII and thrombin
Rates of heparin induced thrombocytopenia?
5%
Affect of UA on period timing
7% early
18% late by 7 days
4% late by 20+ days
What is the decrease in BMD in 6 months tx with GNRH analogouges
4-6%
Most recovers within 18-24 months of tx completion
What is triptorelin
Decapeptyl SR, a GnRH analogue
Initial response to GNrH analogues
“Flare up” - first two weeks see increase in LH, FSH + estrogen, resulting in worsening of symptoms.
Settles by day 20.
Side effects of mefenamic acid
Peptic ulcers, diarrhoea, glucose intolerance in diabetes, heamolytic anaemia (reversible on stopping)
MoA of mefenamic acid
NSAID, prostaglandin production inhibitor.
Inhibits action of cyclo-oxygenase
MoA mifepristone
Antagonises the endometrial and myometrial effects of progesterone
Sensitises the myometrium to cramps produced by prostaglandins
Mifepristone C/I
Severe uncontrolled asthma
Chronic adrenal failure
Inherited porphyria
MoA TXA
Anti fibrinolytic.
Potent competitive inhibitor of activation of plasminogen to plasmin
MoA Doxycycline
Bacteriostatic - inhibition of protein synthesis
What are potential interactions with doxycycline
Penicillin.
Can worsen MG and SLE
Doxycycline C/I
Pregnancy, breastfeeding, retinoids, renal impairment (severe)
C/I TXA
Hx convulsions
DIC
Active/prev. VTE
What class is ceftriaxone
Cephalosporins
(Beta lactam)
How does ceftriaxone work
Inhibitionnof bacterial cell wall synthesis.
Interrupts peptodoglican biosynthesis (due to binding to penicillin binding protein) leading to cell wall lysis and cell death
Ceftriaxone cross reactivity
10% cross reactivity with those with a penicillin allergy, as with all beta-lactams
Side effects of ceftriaxone
Abdo pain, diarrhoea, dizzy, eosophillia, headache, nausea, pseudomembranous enterocolitis, skin reactions
Name cephalosporins
Ceftriaxone, cefotaxime, cefalexin
(CEFs)
What does ceftriaxone not work against
CT, MGen, e coli
Contraindications to Benzathine benzylpenicillin
Peanut and soy allergies
Other penicillin allergies
MoA benzylpenicillin
Beta lactam - bacteriocidal, inhibiting cell wall synthesis
Metronidazole MoA
Treats anaerobic bacteria.
Reduced by intracellular proteins to a form that is cytotoxic to host cell DNA, resulting in strand breakage
Metronidazole side effects
Disulfiram reaction (beware oral drug solutions, may contain alcohol)
Dark urine
Contra indications to metronidazole
Cockayne syndrome
Hypersensitivity
Ciclosporin co administration can cause toxicity
What are macrolides
Azithromycin, erythromycin, clarithromycin
Side effect of prolonged mentronidazole therapy
Peripheral neuropathy
How does Viagra work
Inhibits phosphodiesterase 5
What does phosphodiesterase do
Degrades cGMP in smooth muscle cells
What does the inferior mesenteric ganglion release to act upon the cholinergic receptors on the epidymis
Norepinephrine
What does the somatic (pudendal nerve) release onto the bulbospongiosus
Acetylcholine
Which anti emetic is seritonergic
Ondansetron
Which anti emetic is dopaminergic
Metaclopromide
MoA clomiphene
Estrogen antagonist in the hypothalamus
(Increasing LH and FSH production)
Name HIV integrase inhibitors
Raltegravir, elvitegravir, dolutegravir
Name NNRTIs
Efavirenz, etravirine, delavirdine, nevirapine
Teratogenic NNRTIs
Efavirenz, delavirdine* ask simon
Which nnrti easily crosses the placenta?
Nevirapine
Where are NNRTIs metabolised
Via cytochrome P450
Name the NRTIs
Zidovudine, stavudine, lamivudine, didanosine, abacavir, tenofovir
Name protease inhibitors
Navirs.
Ritonavir, atazanavir, darunavir, indinavir, lopinavir, nelfinavir, saquinavir, tipranavir
What are protease inhibitors metabolised by
Cyp450.
Also inhibits this
What is solifenacin
Competitive muscarinic M3 receptor antagonist
MoA oxybutanin?
Non-selective muscarinic receptor antagonist
MoA mirabegron
Selective B3 adrenergic antagonist