Opiate Antagonists

Opiate antagonists have no agonist properties. They are utilized to reverse opiate induced respiratory depression and to prevent drug abuse.

A. Naloxone

 Pure opiate antagonist , Short duration of action,  Only 1/50th as potent orally as parenterally

B. Naltrexone

Pure opiate antagonist, Long duration of action, Better oral efficacy

Fluconazole: an antifungal used orally,  intravenously or vaginally to treat yeast and fungal infections. Side-effects of systemic administration include hepatotoxicity (liver damage).

• For vaginal candidiasis (vaginal thrush), a once-only oral dose is often sufficient.

DOBUTAMINE

It is a derivative of dopamine and has relatively β1 -selective action and it also activates α1 receptors and do not have D1  receptor agonistic property. It increases the force of myocardial contraction and cardiac output without significant change in heart rate, blood pressure and peripheral resistance. It is used as inotropic agent and for short term management of CHF and also in patients who are unresponsive to digitalis.

ANTIASTHMATIC AGENTS

 Classification for antiasthmatic drugs.
 
I. Bronchodilators

i. Sympathomimetics (adrenergic receptor agonists)

Adrenaline, ephedrine, isoprenaline, orciprenaline, salbutamol, terbutaline, salmeterol, bambuterol

ii. Methylxanthines (theophylline and its derivatives)

Theophylline 
Hydroxyethyl theophylline 
Theophylline ethanolate of piperazine

iii. Anticholinergics

Atropine methonitrate 
Ipratropium bromide

II. Mast cell stabilizer

Sodium cromoglycate
Ketotifen 

III. Corticosteroids

Beclomethasone dipropionate 
Beclomethasone (200 µg) with salbutamol

IV. Leukotriene pathway inhibitors 

Montelukast 
Zafirlukast

Phenytoin (Dilantin): for tonic-clonic and all partial seizures (not effective against absence seizures)

Mechanism: ↓ reactivation of Na channels (↑ refractory period, blocks high frequency cell firing, ↓ spread of seizure activity from focus)

Side effects: ataxia, vertigo, hirsutism (abnormal hair growth), gingival hyperplasia, osteomalacia (altered vitamin D metabolism and ↓ Ca absorption), blood dyscrasias (rare; megaloblastic anemia, etc)

Drug interactions: induces hepatic microsomal enzymes (can ↓ effectiveness of other drugs); binds tightly to plasma proteins and can displace other drugs

Hydromorphone

• About 8-10 times more potent than morphine when given intravenously.
• Slightly shorter duration of action.
• More soluble than morphine, thus higher concentrations may be injected if necessary.
• Better oral/parenteral absorption ratio than morphine, but not as good as codeine or oxycodone.

• It is used for the treatment of moderate to severe pain