Pharmacology Flashcards
Metoclopramide mechanism of action?
Dopamine Antagonist
- Dopamine acts via the hypothalamus to cause inhibition of prolactin secretion and if this is interrupted, prolactin is excreted to excess.
Carboprost
Prostaglandin F2 alpha
Caution is asthmatics because of risk of bronchospasm.
Misoprostol
Prostaglandin E1
Dinoprostone (Cervidil/Propess)
Prostaglandin E2
Enzyme Inducing Anti Epileptic Drugs?
- Carbamazepine
- Phenytoin
- Primidone
- Topirimate
Increased risk of haemorrhagic disease of the newborn therefore babies should be offered 1mg IM vitamin K.
Adalimumab:
1. Drug type and mode of action
2. Used to treat which conditions
3. Guidance in Pregnancy
4. Breastfeeding guidance
- Biologic agent, anti TNF activity
IgG1 antibody - RA, juvenile arthritis, psoriasis, psoriatic arthritis, ank spond, IBD, sarcoidosis
- Actively transported across the placenta. By term, active transportation across the placental barrier ensures that drug levels in the neonate are often in excess of those in maternal circulation.
Moreover, it has a very long half life of 8-20 days which has lead to very high levels in the neonate (98-400% maternal drug levels).
To ensure that low levels of Anti-TNF or none at all - the latest BSR guidelines recommend that Adalimumab be discontinued in the 3rd trimester.
- Safe in BF - recommence immediately PP
Belimumab, Rituximab
1. Examples
2. Mode of action
3. Fetal considerations
- B cell depleting Agents
Also immunoglobulins that cross the placenta from the 2nd trimester onwards. - Transient cytopenias and neonatal B cell depletion that can persist for up to 6 months
List live attenuated vaccines:
- MMR
- Rotavirus
- Smallpox
- Chickenpox
- Yellow fever
Avoid in babies exposed to biologics in pregnancy for 6 months.
Mastitis:
1. Organisms
2. Anti microbial
3. If Pen allergic
- MSSA, Streptococci, MRSA
- Flucloxacillin + Clindamycin
- Vancomycin + Clindamycin
Clindamycin/Teicolplanin are alternatives
(Trough level Vanc 5-20mg/l necessary)
Caesarean section wound infection or IV cannula site infection:
- Organisms
- Anti microbial
- If allergic
- MRSA, MSSA
- MRSA - Vanc + Clindamycin
MSSA - Fluclox + Clindamycin - MRSA - Clindamycin /Teicoplanin
MSSA - Vanc + Clindamycin
Endometritis
- Organisms
- Antimicrobial
- If allergic
- Gram negative anaerobes, streptococci
- Gentamicin (one dose immediately) + Cefotaxime + Metronidazole
- Gent + Clindamycin + Cipro
Acute Pyelo (postpartum):
- Organisms
- Antimicrobial
- If allergic
- Gram neg bacteria, occasionally staph and strep
- Cefotaxime + Gentamicin
- Cipro + agent
ESBL’s: Gent + Meropenem
Toxic Shock Syndrome (post partum):
- Organisms
- Antimicrobial
- If allergic
- Staph / Strep
- Fluclox + Clindamycin + Gent
For MRSA- use Vanc instead of fluclox.
- Vanc + Clindamycin + Gent
Regimen MUST contain antitoxin agent such as Clindamycin or Linezolid.
Lidocaine
Blocks fast voltage gated sodium channels
Antiarrhythmic
Half life 2 hours
Hepatic metabolism
When to stop Infliximab?
Stop at 16/40
When to stop Etanercept?
Stop prior to 3rd trimester
When to stop Certolizumab?
Safe all trimesters and with BF
When to start ART in HIV +ve pregnant patients?
Should be started at the start of the second trimester (13/40).
The aim is to suppress viral load to < 50 HIV RNA copies/mail plasma but the time of delivery.
Nitrofurantoin and cautions postnatally?
CI for use directly in infants < 1 month old or in those with G6PD deficiency due to potential for haemolysis.
Most pregnancy friendly anti-TNF drug safe throughout all trimesters?
Certolizumab
Not actively transported across the placenta like other biologics and doesn’t accumulate.
Antimuscarinic Drugs used in OAB?
Oxybutinin - first line, immediate release
Solifenacin
Tolterodine
Darifenacin
Mirabegron
Beta 3 adrenergic agonist
2nd line treatment for OAB
Desmopressin (DDAVP)
- Mode of action
- Uses
- Cautions
- SE’s
- Synthetic analogue of vasopressin
- Can increase levels of both factor VIII and VWF 3-4 fold
- Avoid in women with PET. Antiduretic properties mean fluid restrict to 1L/ 24 hours or check electrolytes.
- Flushing, headache, hypotension
** clinicians should be aware that patients with type 2B VWD may develop thrombocytopaenia following DDAVP treatment **
Side effects of TB drugs?
Rifampicin - discolouration of urine, sweat, saliva
Isoniazid - peripheral neuropathy
Pyrazinamide - arthralgia, gout, photosensitivity
Ethambutol - gout, neuritis
Half life of thyroxine?
6-7 days
Take on an empty stomach to maximise absorption.
Drugs inhibiting absorption of Levothyroxine?
FeSO4
Calcium salts
Cholestyramine
Fetal risks with Lithium in Pregnancy?
- Lithium increases the rate of fetal heart defects to 60/1000 from 8/1000 in the general population.
- Lithium increases the risk of Ebstein’s anomaly from 1/20,000 to 10/20,000
Fetal risks with Carbimazole?
- Aplasia cutis congenita (absence of portion of skin, often localised to the head)
- Craniofacial malformations (choanal atresia, facial dysmorphism)
- Defects of abdominal wall and GIT (exomphalos, oesophageal atresia)
- VSD
PTU and Carbimazole SE’s?
- Puritis
- n+v
- Diarrhoea
- Agranulocytosis - discontinue therapy. If women on Carbimazole present with evidence of infection such as sore throat, perform FBC!
- Fetal goitre - 10%
- Transient neonatal hypothyroidism - 1-5%
- Drug rash 5%
Olanzapine increased risk
Of what in Pregnancy?
Gestational Diabetes
Clomiphene Citrate
- Weak oestrogen, competes with endogenous oestrogens for receptors at the hypothalamus, blocking negative feedback of endogenous oestrogens.
- GnRH levels rise and stimulate gonadotropin release resulting in ovarian stimulation and a rise in serum oestradial
- Effective of ovulation induction in women with anovulatory fertility
- 5-10% risk of multiple pregnancy, risk of OHSS
- SE: visual disturbance, hot flushes, abdo discomfort, breast tenderness, weight gain, menorrhagia, dizziness, hair loss, depression
Tamoxifen
Breasts:
- antagonises oestrogen action on breast
- 50% reduction in recurrence and 25% reduction in mortality (ER +ve breast ca)
Reproductive Tract:
- anti-oestrogenic effects in pre menopausal women
- oestrogenic effects in post menopausal women with stimulation of the endometrium, myometrium and vagina. There is stimulation of fibroid growth, induction/ re activation of endometriosis and adenomyosis.
Risk of EC for tamoxifen users 1.6/1000 vs 0.2/1000 placebo.
Serum lipids:
- reduction in serum cholesterol and LDL cholesterol in post menopausal women.
- risk of VTE increased 4.7 - 5.7 fold.
Clonidine
1. Mode of action
2. Use
- Alpha 2 agonist
- Can be used to treat Vasomotor symptoms in Menopause - oral ineffective, trans dermal effective
Side effects of Atosiban?
Nausea, Vomiting
Tachycardia
Hypotension
Headache
Hyperglycaemia
Hot flushes
Injection site infection
Side effects of Nifedipine?
Headache
Flushing
Tachycardia
Palpitations
Hypotension
Dependent oedema
Constipation
Increased urinary frequency
Eye pain
Visual disturbance
Tranexamic Acid
1. Mechanism of action
Prevents conversion of plasminogen to plasmin. This prevents fibrin degradation and preserves the framework of fibrin’s matrix structure.
Which TB drug is associated with hepatitis?
Isoniazod
Peak concentration of Misoprostol:
1. Oral/Sublingual
2. Buccal/Vaginal
- Oral/Sublingual - 30 minutes
- Buccal/Vaginal - 70-80 minutes
Warfarin:
1. MOA
2. Half life
3. When to stop pre op
- Vit K epoxide reductase inhibitor
- Half life: 36 hours
- Stop 5/7 pre op. Check INR the day before surgery, if > 1.5 may need Vit K. Consider bridging with LWMH if high risk VTE.
Apixaban + Rivaroxaban
1. MOA
2. Half life
3. When to stop pre op
- Factor Xa inhibitor
- Apix: 8 hours, rivarox: 9hrs
- Low bleeding risk, stop:
a) Creat clearance > 30 - stop 24 hrs
b) Creat clearance < 30 - stop 48 hrs
High bleeding risk, stop:
Creat clearance > 30 - stop 48 hrs
Creat clearance < 30 - stop 72 hours
Lithium:
1. Risk of cardiac malformation?
2. Timing of fetal ECHO?
3. When to check lithium levels?
4. Anaesthetic consideration?
5. BF advice
6. Maternal considerations
- 2% (BG risk 0.6-1.2%)
- 18-22 weeks consider fetal echo
- Lithium levels every 4 weeks until 36/40 then weekly thereafter.
- Can interact with neuromuscular blocking agents - anaesthetic assessment 3rd trimester
- BF not recommended due to neonatal toxicity
- Risk of maternal diabetes Insipidus
Lithium level:
1. Sub therapeutic
2. Level that lithium toxicity develops
3. Fatal cardio toxicity and neurotoxicity
- < 0.6
- > 1.2
- > 2
