Laxatives at a glance

There are 4 types

Bulk forming agents
- swell when mix with water
- adding bulk in stool
- bran, methylcellulose

Stool softeners
- there are two mechanisms of action

stimulate the gut muscle to contract faster so that there will be less water reabsorbed at large intestine, making stool soft. example, docusate sodium

or lining up the faeces (oil based) so that water could not be absorbed. example, paraffin oil

Stimulants
- three ways of action

stimulate intestinal motility

increase fluid secretion

reduce water absorption

- example : senna, bisacodyl

Osmotic laxatives
- draws water into the colon
- example : lactulose

First Line Anti-TB drugs

Isoniazid (H)
- inhibit synthesis of mycolic acid (cell wall)
- selective for mycobacterium
- mechanism of action : Inhibit enoyl-CoA reductase of fatty acid synthase and formation of covalent complex with carrier protein

Rifampicin (R)
- broad spectrum
- mechanism of action :bind to Beta subunit of bacterial-DNA-dependent RNA polymerase

Pyrazinamide (Z)
- never used on its own
- mechanism of action : TB has pyrazinamidase (an enzyme). Convert pyrazinamide to pyrazinoica cid. Pyrazinoic acid inhibits fatty acid synthesis of TB

Streptomycin (S)
- aminoglycoside
- mechanism of action : causing misreading and inhibition of protein synthesis on bacterial ribosomes

Ethambutol (E)
- anabinoglycan is a component of mycobacterial cell wall
- mechanism of action : inhibit mycobacterial arabinosyl transferase involve in polymerization of arabinogalactan

Combinations :
Initial / intensive phase : HRZ, HRZS or HRZE
Maintenance phase : HR

Drugs for Asthma List

Sympathomimetics (B2 receptor agonits)

• Non selective : adrenaline
• Selective short acting : salbutamol, terbutaline, fenoterol
• Selective long acting : salmeterol, formoterol

Methylxanthine

• Oral : Theophylline
• IV : Aminophylline

Anticholinergics

• ipratropium bromide
• tiotropium

Corticosteroids

• Systemic : hydrocortisone (IV), prednisolone (oral)
• Inhaled : beclomethasone, budesonide, fluticasone, triamcinolone

Anti-IgE monoclonal antibodies

• Omalizumab

Mast cell stabilizers (prevention use only)

• Sodium Cromoglycate
• Nedocromil

Leukotriene pathway inhibitor

• Leukotriene receptor antagonist : montelukast, zafirlukast
• Leukotriene synthesis inhibitor : zileuton

How drinking grape juice can be dangerous when you take certain drugs?

• In the intestine there is cytochrome P450, which is part of the detoxification system that detoxifies foreign materials (the drugs) going into the body
• Thus, in normal condition, some of the drugs are metabolized (which means becoming less) in the intestine before it goes into the circulation

• Grape juice inhibits cytochrome P450
• The intestine could not metabolized the drugs as it normally does
• There will be high quantity of the drugs going into the circulation
• This means overdose of drugs
• This means danger

Aspirin overdose : acidosis or alkalosis?

Both, but overdose of aspirin usually cause neurological side effects rather than acidosis or alkalosis

Acidosis, metabolic - aspirin is an acid
Alkalosis, respiratory - aspirin can stimulate the respiratory center

Atenolol

- beta-1 receptor selective antagonist
- slowing down the heart and reducing its workload
- does not pass through the blood-brain barrier
- hypertension, coronary heart disease, arrhythmias, angina