# 23 - 6. Other agents adverse effects

# 6. Other agents - adverse effects

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6. Other agents - adverse effects 
Cholinesterase inhibitors: Donepezil causes nausea, diarrhea, insomnia, vomiting, muscle 
cramps commonly. Rivastigmine causes similar symptoms albeit at a higher frequency of some. 
Galantamine too has a similar profile. Tacrine is not used anymore in UK due to reports of fatal 
hepatotoxicity. 
By increasing central and peripheral cholinergic stimulation cholinesterase inhibitors, can 
1. Increase the risk for GI bleeding especially in NSAID users or patients with 
peptic ulcer. 
2. Produce bradycardia, especially in those with supraventricular conduction 
delay, 
3. Exacerbate COPD 
4. Cause urinary retention 
5. Increase seizure risk 
6. Prolong the effects of succinylcholine-type muscle relaxants 
Rivastigmine’s  metabolism  does  not  depend  on  liver  P450  enzymes,  and, therefore, no drug 
interactions related to the P450 system have been observed. Memantine does not inhibit or 
induce hepatic microsomal enzymes; because it is excreted in the urine predominantly as 
unchanged drug, it is unlikely to be affected by drugs that affect hepatic enzyme function. 
Stimulants and other drugs used for ADHD: The most common adverse effects are anxiety, 
irritability, insomnia, tachycardia, cardiac arrhythmias, and dysphoria with decreased appetite. 
Tolerance usually develops for appetite loss. Less commonly self-limited exacerbation of 
movement disorders, such as tics and dyskinesias, may occur. 
Stimulants are linked to growth suppression. Bruxism and restlessness are also reported. 
Pemoline is associated with fulminant hepatic failure and is no longer used widely. Dependence 
can occur with methylphenidate though this is rare at doses used for ADHD. 
Side effects of atomoxetine are appetite loss, sexual dysfunction and dizziness; severe liver injury 
in has also been reported. 
Clonidine is not a popular option for treating tics/ADHD due to high rates of hypotension 
associated with it. 
 
Hypnotics: Overdose of benzodiazepines can produce slurred speech, incoordination, unsteady 
gait, nystagmus, impairment in attention or memory, stupor or coma and behavioural changes 
(inappropriate sexual or aggressive behaviour, mood lability, impaired judgment etc.).