A very close friend of mine took 60 0.2mg Clonidine tablets attempting suicide and said he could feel his blood pressure crashing within 5 minutes, became dizzy and disoriented, but his family called the police, he said he was walking down the street trying to get away and lost consciousness and woke up in the hospital several days later.
He was in the ICU for about 2 weeks on a Naloxone IV drip he is still alive, and from the research I have done it isn't exactly reliable but in theory it should work
Would work much better in combination
Clonidine + Propanolol or Clonidine + Atenolol
However the LD50 for clonidine in humans sounds ridiculously high from what I found
But LD50s are estimates at best and are based off of animal studies they do not actually give lethal doses to people in human clinical trials
Lethal dosage
The oral LD50 for clonidine in mice is 206 mg/kg and for rats, 465 mg/kg.[citation needed] In humans, lethality is rare with a small number of reported deaths. Morbidity, in terms of cardiorespiratory and CNS dysfunction, generally tends to be more severe in young persons than in adults.[citation needed]
Overdose
Symptoms of clonidine overdose include constriction of pupils of the eye, drowsiness, high blood pressure followed by a drop in pressure, irritability, low body temperature, slowed breathing, slowed heartbeat, slowed reflexes, and weakness.[citation needed]
There are case reports that show naloxone may be a useful antidote in treating clonidine overdoses. However, this is not in widespread clinical use.[22]
I would need to know the names of the medications. Please provide more information as I cannot answer your question without it.